McQuay FCVC Manual

Installation and Maintenance Manual IM 980-1
ThinLine3G Vertical Fan Coils
Type FCVC, FCVH, FCVS and FCWC Vertical Design
Group: Applied Air Systems
Part Number: 910102984
Date: May 2011
© 2011 McQuay International
200 to 1200 cfm
IM 980-1
Model FCVC
Model FCVS

2McQuay IM 980-1
Table of Contents
IM 980-1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
General Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
Receiving and Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
Pre-Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
Fresh Air Box Openings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Recommended Maintenance Clearance . . . . . . . . . . . . . . . . . . . . . . . . . 5
Duct Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Uncrating and Inspecting the Unit . . . . . . . . . . . . . . . . . . . . . . . . . .6
Mounting Unit to Wall . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Water Piping Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
General Guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Connecting to a Factory-Installed Valve & Piping Package . . . . . . . . . . 8
Field-Installed Valve & Piping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Shutoff/Balancing Valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Condensate Drain Connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Steam Piping Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
Two-pipe systems with electric heat . . . . . . . . . . . . . . . . . . . . . . .10
External Insulating Requirements . . . . . . . . . . . . . . . . . . . . . . . . .10
Electrical Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
Standard Electrical Connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Thermostat and Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
Initial Startup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
Cleaning & Flushing the Water System . . . . . . . . . . . . . . . . . . . . . . . . . 11
Operating Limits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Venting Hydronic Coils . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Operation and Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
Manual 4-Position Fan Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Unit-Mounted, Mechanical Thermostat With 4-Position Fan Switch . . . 13
Digital Thermostats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Low-Voltage (LV) Interface Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Operation and Maintenance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
Fresh Air Damper . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Condensate Overflow Detection Device . . . . . . . . . . . . . . . . . . . . . . . . 16
Leveling Legs Option . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Cabinet Rear Extension Kit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Electric Heat Over-Temp Reset Button . . . . . . . . . . . . . . . . . . . . . . . . . 17
Key-lock Access Door Kit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
General Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Filter Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Condensate Drain Pans . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Physical Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20
Unit Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20
Shipping Weights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20
Unit Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
Factory-Installed Valve & Piping Packages . . . . . . . . . . . . . . . . .25
Wiring Diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26
Model Number Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29
IM 1121 - Hideaway Unit Discharge Conversion Kit . . . . .35
Safety Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35
Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35
IM 1023 - Fresh Air Damper Kit . . . . . . . . . . . . . . . . . . . . . .37
Installation Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .37
Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .38
Cold Weather Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
IM 1028 - Fresh Air Damper Motor Kit . . . . . . . . . . . . . . . .39
Installation Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39
IM 1024 - Cabinet Rear Extension Kit . . . . . . . . . . . . . . . . .41
Installation Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41
IM 1021 - Key-Lock Access Door Kit . . . . . . . . . . . . . . . . .43
IM 1014 - MTA/B 155 Electronic Thermostats . . . . . . . . . .45
Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .45
Thermostat Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .45
Ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .46
Wire Lead Colors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .46
Application Notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .46
Wiring Diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .46
IM 1089 - Field Installation of MT155 Thermostats . . . . . .47
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .47
Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .47
Two-pipe system (Cooling or Heating) . . . . . . . . . . . . . . . . . . . . . . . . . .47
Four-pipe system (Cooling and Heating) . . . . . . . . . . . . . . . . . . . . . . . .49
IM 1015 - MT 158 and MT 168 Digital Thermostats . . . . . .51
Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .51
Thermostat Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .52
Mode Button Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .52
Fan Speed Switch Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .52
Up/ Down Arrow Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .52
Setback Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .52
Pipe Sensor Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .52
Ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .52
Service Menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .52
Application Notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .53
Power-Up Operating Sequence . . . . . . . . . . . . . . . . . . . . . . . . . . 53
IM 1016-1 - MTB 158 Microprocessor Thermostats . . . . .55
Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .55
Thermostat Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .56
Mode Button Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .56
Fan Speed Switch Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .56
Up/ Down Arrow Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .56
Setback Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .56
Pipe Sensor Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .56
Three Wire Floating Valve Operation . . . . . . . . . . . . . . . . . . . . . . . . . . .56
Outside Air Damper Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .56
Application Notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .57
Service Menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .57
Power-Up Operating Sequence . . . . . . . . . . . . . . . . . . . . . . . . . .57
IM 1017 - MT 168 0-10Vdc/4020mA Thermostats . . . . . . .59
Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .59
Electrical Ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .60
Application Notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .60
Thermostat Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .60
Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .60
Service Menu: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .61
IM 846 - MT 170 Thermostats . . . . . . . . . . . . . . . . . . . . . . .63
Installation Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .65
Thermostat Model and Part Number. . . . . . . . . . . . . . . . . . . . . . . . . . . 65
Optional Occupancy Detection Sensors/Kits . . . . . . . . . . . . . . . . . . . . .65
Mounting and Wiring the Thermostat . . . . . . . . . . . . . . . . . . . . . . . . . . .65
Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .67
Thermostat Button Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .67
Verifying Thermostat Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .67
Thermostat Menu Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .68
Fan Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .69
Fancoil Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .70
Setback Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .70
Optional Occupancy Detection Equipment Operation . . . . . . . . . .71
SB200-001 Occupancy Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .71
SD200-001 Occupancy Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .73
SD200-002 Occupancy Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .74
IM 831 - Thermostat Conversion Kit . . . . . . . . . . . . . . . . . .77
Safety Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .77
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .77
Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .77
IM 763 - Automatic Changeover Switch . . . . . . . . . . . . . . .79
Safety Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .79
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .79
Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .79

McQuay IM 980-1 3
General Information
General Information
Thinline™ 3G Vertical Fan Coils are intended for use in single
zone applications. They are available in sizes from 200 to 1200
cfm. Figure 2 describes the main features of these units and
can be refered to for component placement. These units are
available in two-pipe configurations with one hydronic coil,
with or without electric heat. They are also available in four-
pipe configurations with one primary coil and a secondary
reheat or preheat coil. A variety of factory-built piping
packages are available, either factory or field-installed.
Units are available with a variety of thermostat and fan speed
control options, which can be mounted on the unit or shipped
loose for mounting in the controlled space. Options include:
•Four-position fan switch (Off/Lo/Med/Hi).
•Manual thermostat with On/Off valve control.
•Digital thermostat with a variety of control options,
including fan control, On/Off or modulating valve control
and automatic changeover from heating to cooling on two-
pipe systems.
•Low-voltage interface board for connecting a unit to
controls provided by others. The controls interface option
includes a 24 volt AC transformer and interface terminal
strips.
•No Controls, with pigtail connections to the unit’s fan motor
wiring harness.
Figure 1: Nomenclature (see Table 1, page 29 for complete model number description)
Figure 2: Unit Features
FC V S - 1 02 A
Unit Type
FC = Fan Coil
FH = Cabinet Unit Heater
Unit Configuration
V= Vertical
W = Wall Hung (future)
Cabinet Type
C = Cabinet (Flat Top)
S = Slope Top
H = Hideaway
Voltage
A = 115/60/1
E = 208-230/60/1
J = 277-265/60/1
Unit Size
02 = 200 CFM
03 = 300 CFM
04 = 400 CFM
06 = 600 CFM
08 = 800 CFM
10 = 1000 CFM
12 = 1200 CFM
Design Series
Multiple Control Options
•From 3-speed switch to LV interface board
•Remote or unit-mounted
•3-speed or staged fan Multiple
Configurations
•Flat top
•Slope top
•Hideaway
•Wall mounted
Multiple Coil Options
•2, 3 or 4-row main coil
•1 or 2-row preheat or 1-row
reheat coil
•Hot water or steam
•Same or opposite end
connections
Multiple Grille Options
•Stamped discharge
louver
•Multi-directional grilles
•Return grille option
Software Selectable
Valve & Piping Packages
•Factory-mounted, wired and
tested or factory-assembled and
shipped loose for field mount
•Normally Closed or Open, On/Off
or modulating valves
Easily Removed Drain Pan & Motor Assembly
•For easy maintenance and service
•Sloped, polymer drain pan for good IAQ
Optional Secondary Drain Pan
(Supplied with Piping Packages)
•Noncorrosive
•Easily removed

4McQuay IM 980-1
General Information
Receiving and Storage
Upon receipt of the equipment, check carton for visible
damage. Make a notation on the shipper’s delivery ticket
before signing. If there is any evidence of rough handling,
immediately open the cartons to check for concealed damage.
If any damage is found, notify the carrier within 48 hours to
establish your claim and request their inspection and a report.
The Warranty Claims Department should then be contacted.
Do not stand or transport the machines on end. For storing,
each carton is marked with “up” arrows.
Temporary storage at the job site must be indoor, completely
sheltered from rain, snow, etc. High or low temperatures
naturally associated with weather patterns will not harm the
units. Excessively high temperatures, 140°F (60°C) and
higher, may deteriorate certain plastic materials and cause
permanent damage.
Pre-Installation
Before beginning installation, please read this publication in its
entirety. Directions given in this bulletin for right and left sides
or coil hand assume a position facing the front of the unit.
1To prevent damage, do not operate this equipment for
supplementary heating and cooling during the
construction period. Doing so will void the warranty.
2Inspect the carton for any specific tagging numbers
indicated by the factory per a request from the installing
contractor. At this time the voltage, phase and capacity
should be checked against the plans.
3Check the packing list and unit identification/tagging
numbers against the plans to verify that the unit is being
installed in the correct location. The unit data plate is
attached to the deck plate on the front of the fan coil (see
Figure 3). Remove the front panel on cabinet units to
access it. The panel contains specific information on
standard components as listed in Figure 1, page 3 and in
Table 1, page 29.
Figure 3: Data Plate Location
4Before installation, check the available dimensions
where the unit is to be installed against the dimensions of
the unit.
5Note the location and routing of water piping,
condensate drain piping, and electrical wiring. The
locations of these items are clearly marked on submittal
drawings.
6An installing contractor may find it beneficial to confer
with piping, sheet metal, and electrical foremen before
installing any unit.
Note: Check the unit data plate for correct voltage with the
plans before installing the equipment. Also, make
sure all electrical ground connections are made in
accordance with local code.
7The unit is not designed to be free-standing. Install it
against a wall or other flat surface that meets fire and
electrical codes requirements for heating and cooling
devices.
8After installation, cover the unit with the shipping carton
or other appropriate material for protection during
finishing of the building. This is critical while spraying
fireproofing material on bar joists, sandblasting, spray
painting and plastering. Damage to the unit due to a
failure to protect it during finishing of the building is not
covered by the warranty.
Fresh Air Box Openings
ThinLine 3G Vertical Fan Coils can be installed with an
optional fresh air box that is designed to let in outside air while
preventing water (such as rain) from getting into the unit itself.
If used, prior to unit installation, confirm that the exterior wall
opening and the wall box are ready and installed in accordance
with the job plans.
IMPORTANT
This product was carefully packed and thoroughly inspected
before leaving the factory. Responsibility for its safe delivery
was assumed by the carrier upon acceptance of the shipment.
Claims for loss or damage sustained in transit must therefore
be made upon the carrier as follows:
VISIBLE LOSS OR DAMAGE
Any external evidence of loss or damage must be noted on the
freight bill or carrier’s receipt, and signed by the carrier’s agent.
Failure to adequately describe such external evidence of loss
or damage may result in the carrier’s refusal to honor a
damage claim. The form required to file such a claim will be
supplied by the carrier.
CONCEALED LOSS OR DAMAGE
Concealed loss or damage means loss or damage which does
not become apparent until the product has been unpacked.
The contents may be damaged in transit due to rough handling
even though the carton may not show external damages.
When the damage is discovered upon unpacking, make a
written request for inspection by the carrier’s agent within
fifteen (15) days of the delivery date and file a claim with the
carrier.

McQuay IM 980-1 5
General Information
Recommended Maintenance Clearance
Cabinet units have removable front and side panels for easy
access to components for service and maintenance. The fan
assembly and main drain pan are easily removable from the
front for cleaning. See Accessing/removing the main drain pan
and motor assembly‚ page 19 for more information.
Figure 4 shows recommended maintenance clearances: 0.5
inches (13 mm) on either side and 10 inches (254 mm) in front.
Units are referred to as either right-hand or left-hand
depending upon the piping connection. Hand is designated by
facing the front of the unit (airflow discharges from the front
or top). Unless it is a special-order unit, the control panel is
always on the end opposite the cooling coil pipe connections.
Figure 4: Recommended maintenance clearance
Duct Connections
Air ducts, when used with hideaway units, should be installed
in accordance with local and national codes, including
National Fire Protection Association standards for the
Installation of Air Conditioning and Ventilating Systems and
the National Fire Protection Association standards for the
Installation of Air Conditioning and Ventilation Systems other
than Residence Type.
A one-inch duct collar is provided on units with a ducted
return and/or discharge to attach ductwork. McQuay
recommends using galvanized sheet metal ductwork. Slide the
sheetmetal duct over the duct collar flange of the unit, seal the
joint and fasten with sheetmetal screws.
Note: Do not run screws through the removable front panel on
hideaway units.
Ductwork Recommendations
Follow the general recommendations listed below when
installing the ductwork for the unit.
1Discharge ductwork should run in a straight line,
unchanged in size or direction, for a minimum distance
of three fan diameters from the unit (approximately 20
inches).
2Avoid making sharp turns when making duct turns and
transitions. Use proportional splits, turning vanes, and air
scoops when necessary.
3When possible, construct and orient supply ductwork
turns in the same direction as the fan rotation.
Safety
Follow all safety codes. Wear safety glasses and work gloves.
Use a quenching cloth for brazing operations. Have a fire
extinguisher available. Follow all warnings and cautions in
these instructions and attached to the unit. Consult applicable
local building codes and National Electrical Codes (NEC) for
special requirements.
Recognize safety information. When you see a safety symbol
on the unit or in these instructions, be alert to the potential for
personal injury. Understand the meanings of the words
DANGER, WARNING, and CAUTION. DANGER identifies
the most serious hazards that will result in death or severe
personal injury; WARNING means the hazards can result in
death or severe personal injury; CAUTION identifies unsafe
practices that can result in personal injury or product and
property damage. Improper installation, adjustment, service,
maintenance, or use can cause explosion, fire, electrical
shock, or other conditions which may result in personal injury
or property damage. This product must be installed only by
personnel with the training, experience, skills, and applicable
licensing that makes him/her “a qualified professional
HVACR installer.”
0.5 in
13 mm
0.5 in
13 mm
10 in
254 mm
DANGER
Disconnect all electrical power before servicing unit. Electrical
shock will cause severe injury or death.
WARNING
Hazardous Voltage!
Usecopperconductors only. Unit terminals are not designed to
accept other types of conductors. Failure to do so may cause
damage to the equipment.
WARNING
Personal injury hazard. Wear protective gloves to avoid
possible cuts and abrasions from exposed edges. Avoid
contact with sharp edges.
CAUTION
Cleaning agents may cause serious damage to internal
components, such as aluminum coils and electronic controls,
etc. Do not operate fan coil while building maintenance
cleaning agents are in use..

6McQuay IM 980-1
Installation
Installation
Uncrating and Inspecting the Unit
1Carefully remove the packaging, remaining alert to any
signs of shipping damage. Be careful not to discard
components that may be included with the packaging.
2If the unit is damaged, file a claim with the carrier.
Notify the local McQuay representative immediately.
3You may want to retain some or all of the packaging to
provide jobsite unit location information and temporary
protection for the fan coil after installation. Be sure to
dispose of plastic packaging and protective cardboard
properly, in accordance with local recycling rules and
guidelines.
4Touch up painted panels if necessary. If panels need
paint, sanding is not necessary. However, clean the
surface of any oil, grease, or dirt residue so the paint will
adhere. Purchase factory approved touch up paint from
your McQuay representative or McQuay Factory
Service.
Mounting Unit to Wall
1Consult job blueprints for unit location.
2Clean area where unit is to be installed, removing all
construction dirt and debris. Remove any mouldings at
the floor or wall.
3Remove the unit from the shipping carton and plastic
covering. Save the carton and plastic to use as a
protective cover after the installation is complete.
4On cabinet units, remove the screws shown in Figure 5
that secure the right and left cabinet corner panels to the
subbase. For ease of installation, you may also remove
the center panel. Lift the panels up and out.
Note: Set the unit panels aside where they will not be
damaged. Take care not to bend the mounting tabs
on the bottom of the panels.
Figure 5: Cabinet Side Panel Removal
5STOP! If an outside air damper kit is to be installed,
install it now. See Fresh Air Damper‚ page 16 and the IM
included with the damper for more information.
6Position the chassis/subbase against the wall where the
unit is to be installed. Make sure that the area under the
unit is free of combustible materials such as carpet. For
cabinet units, the wall must act to close off the back of
the unit.
7For hideaway units, if you are using McQuay’s
decorative wallplate, use blocks or other suitable
material to raise the unit off the floor a minimum of 1.5
inches (38 mm).
8Make sure electrical and piping connections are in the
proper location within the end compartments. The
control box is in the end compartment opposite the main
coil piping connections. Power to the unit is hooked up
through the junction box/disconnect box located under
the control box. See Figure 30, page 21 through
Figure 33, page 24 for location information.
9Use a level to check that the unit is level both front to
back and side to side (see Figure 6). Adjust the unit as
needed using the optional leveling legs or shims.
10 The chassis has a series of slots on the back flange to
mount the assembly to the wall. Transfer a mark with a
marker or pencil to the wall at the mounting hole
locations.
11 Insert fasteners through the mounting holes in the chassis
and secure the unit to the wall. Do not over-tighten
fasteners. It is the installing contractor’s responsibility to
WARNING
Plastic packaging is a suffocation hazard, dispose of properly.
Keep away from children.
WARNING
Installation and maintenance are to be performed by qualified
personnel who are familiar with local codes and Regulations,
and experienced with this type of equipment..
CAUTION
Personal injury hazard. Wear protective gloves to avoid
possible cuts and abrasions from exposed edges. Avoid
contact with sharp edges.
CAUTION
It is critical that the unit is level to avoid condensate
accumulation in the drain pan. This is especially important
when using a stainless steel drain pan which does not have a
sloped bottom.

McQuay IM 980-1 7
Installation
select the correct fasteners for each unit to meet local
codes. At location(s) where no stud is present, secure
with a Toggle bolt or equivalent.
Note: Use a minimum of two fasteners on each side to
secure the unit (field supplied).
12 On cabinet units, reinstall the side/quarter panels in
reverse order as performed in step 4.
13 If you raised the unit off the floor in step 7, remove the
block or other material supporting the bottom of the unit.
Make sure the unit is securely fastened to and supported
by the wall mounts.
14 Cut out one side and the bottom of the shipping carton,
leaving the top and three sides to place over the unit for
protection during construction.
Figure 6: Unit Mounting
Water Piping Connections
General Guidelines
1Piping can be steel, copper or PVC, but must comply
with local codes.
2Proper ventilation is required for soldering. When
soldering, use a quenching cloth to protect fan coil
components from overheating damage—melting
insulation, also damage to valves, wiring, electronics,
sensors, etc. See Figure 7. When McQuay provides valve
packages with unions, o-rings are included. When
soldering near unions, remove the o-rings before heating.
Figure 7: Protect Components From Overheating
3If sealant compound is not provided for flexible hose
fittings, apply Teflon tape to the connections to help
prevent leaks.
4Ensure proper insulation of supply and return piping.
Proper insulation prevents loss of fan coil capacity,
overheating of end compartments, and/or moisture
dripping.
5The piping to and from the unit must be protected from
outside air and freeze conditions. It must be suitably
insulated for condensation and for heat loss or gain.
Penetrations entering the unit end compartments must be
fitted/sealed for unit integrity.
6Exterior condensate may be an issue if field piping does
not have a control valve. Review the supply and return
header locations in the Dimensions drawing beginning
on page 21. If using a field-assembled piping package,
allow sufficient room to install the secondary drain pan.
Piping for chilled water should not extend over the edges
of the secondary condensate drain pan.
7Supply and return shutoff valves are recommended at
each unit. The return valve is used for balancing and
should have a “memory stop” so that it can always be
closed off, but can only be re-opened to the proper
position for the flow required.
8Primary coils are factory-equipped with vents for venting
the system, but secondary coils (preheat or reheat) are
not. If the unit is not equipped with a factory-built piping
packages, then a vent must be added. See step 1, page 8.
9Be sure to install control valves on the correct fan coil.
Indiscriminate mixing of valves in the field can result in
valves improperly sized for the desired flow rate, which
can result in poor operation and coil freezeups.
10 Install control valves so there is at least 2" (51mm)
minimum clearance to remove the actuator from the
valve body.
Make sure unit is
level front-to-back
and side-to-side.
Use a quenching cloth
when soldering or
brazing to avoid
overheating the piping
components and
creating valve damage
or eratic operation.

8McQuay IM 980-1
Installation
11 Do not connect a unit to the supply and return piping
until the water system has been cleaned and flushed
completely. After this is done, the initial connection
should have all valves wide open in preparation for water
system flushing.
12 Condensate piping can be steel, copper, or PVC. A
means of disconnection must be furnished to facilitate
fan section removal.
13 No point of the drain system may be above the drain pan
of any unit.
14 Automatic flow control devices must not be installed
prior to system cleaning and flushing.
15 Check local code for any requirement for electrical
fittings.
Connecting to a Factory-Installed Valve &
Piping Package
To view connection locations for factory-installed valve &
piping packages, see Figure 34, page 25. Before installing
supply and return lines to a factory piping package, review the
following items.
•All piping connections are 5/8" O.D.S. (1/2" nominal)
female copper connections.
•Supply and return piping should not interfere with the
secondary drain pan or condensate line.
•The installer must provide adequate piping system filtration
and water treatment.
•McQuay Deluxe and Enhanced piping packages include a
strainer which prevents debris from entering the coil. Clean
the strainer regularly.
•The fan coil ships with brackets to adequately support the
piping package during shipment. Remove these brackets
before connecting water piping to the unit.
•Set end valves to the fully open position to prevent damage
to the valve seat during brazing.
•Remove the secondary drain pan, if in place, to prevent
exposure to dripping solder or excessive temperatures.
•Solder water piping connections to supply and return end
connections. Avoid overheating factory soldered joints to
prevent the possibility of leakage.
•Insulate fan coil piping to secondary drain pan connections
and any piping that is not above the secondary drain pan.
Field-Installed Valve & Piping
Review General Guidelines‚ page 7 before beginning. Then
carry out the following steps to install valves and piping.
1For units equipped with a secondary coil make sure that
an air vent is included in the return line piping (see
Figure 8). Primary coils are factory-equipped with vents
for venting the system, but secondary coils (preheat or
reheat) are not.
Figure 8: Secondary Coil Air Vent
2Remove the secondary drain pan, if in place, to prevent
exposure to dripping solder or excessive temperatures.
Note: Factory-installed valve and piping packages include
the secondary drain pan, which ships with the unit.
For other arrangements, the secondary drain pan
must be ordered separately.
3Push the main drain pan condensate hose back inside the
end plate to prevent it from getting burned when making
sweat connections. Be sure to pull the hoses back
through and route to the secondary drain pan when the
end panel has cooled.
4Slide ½" copper tubing or connection couplings (installer
provided) onto the coil connections. Solder the joint
using a good-quality, lead-free solder to provide a
watertight connection.
5After connections are complete, insulate all piping to the
coil connections as necessary to prevent condensate from
dripping outside of the secondary drain pan.
6Install the optional secondary drain pan.
Shutoff/Balancing Valve
Each fan coil should be at least be equipped with shutoff
valves on both the supply and return lines for easy
serviceability and removal if it becomes necessary. We suggest
using our combination shutoff/balancing valves between the
IMPORTANT
Venting is required on the return piping for secondary preheat
or reheat coils. It is included on factory-built piping packages,
but must be added by the installing contractor for field-installed
piping. See Figure 8.
WARNING
Avoid overheating when soldering field connections to the coil
to prevent leakage, overheating of the copper tubes, and
melting of valves, factory-soldered joints or component
gasketing. A quenching cloth is recommended. See Figure 7.
Secondary
Coil Air
Vent

McQuay IM 980-1 9
Installation
main supply line and the fan coil unit. These can be furnished
as part of a factory-installed valve & piping package or they
can be installed in the field. The balancing valve installed on
the return line is used to adjust the water flow to provide the
best performance.
Condensate Drain Connection
1Connect a copper or plastic pipe to the 7/8 inch copper
pipe on the secondary drain pan. This should be a
mechanical connection that allows easy removal of the
secondary drain pan when servicing the piping end
pocket.
2Slide the pipe over the drain pan nipple and tighten the
collar on the pipe with a hose clamp (installer supplied).
A drain line pitch of one inch per ten feet of drain line
run must be maintained to provide adequate condensate
drainage.
3The drain line should be supported to prevent undue
stress on the secondary drain pan. Make sure the drain
line is free of kinks and obstructions and the secondary
drain pan is level.
4The installer is responsible for adequately insulating
field piping. See External Insulating Requirements‚ page
10 for more information.
Figure 9: Condensate Drain Connection
Automatic Changeover Sensor
Two-pipe changeover units require an automatic changeover
switch or pipe sensor that determines heating or cooling mode
based on the supply water temperature. A switch is provided
with a unit-mounted analog thermostat on a two-pipe system.
A sensor is provided with any digital control on a two-pipe
system. On units with a factory-installed valve & piping
package, the factory straps the changeover switch or sensor to
the piping supply water pipe. See Figure 10.
For a two-pipe system with intermediate electric heat, a second
set is required including a changeover switch or sensor.
Figure 10: Changeover switch & sensor attachment
If the unit does not have a factory-installed valve & piping
package, the changeover switch or sensor can be ordered for
field installation. The installer should attach the sensor or auto-
changeover switch parallel to and in direct contact with the
supply water pipe.
Note: The installer is responsible to ensure the changeover
sensor is installed in a location that can sense active
water temperature. Otherwise, the unit may fail to sense
the correct operating mode and disable temperature
control.
When using field-supplied three-way valves, install the
changeover sensor upstream of the valve on the supply water
pipe. When using field-supplied two-way control valves,
install the changeover sensor in a location that will detect
active water temperature. The unit must always be able to
sense the correct system water temperature, regardless of the
control valve position.
Note: The maximum length of the automatic changeover wire
cannot exceed ten feet from the control panel to the
sensor. If the wire extends beyond the unit chassis, use
shielded conductors to eliminate radio frequency
interference (RFI).
Steam Piping Connections
Make piping connections to the steam coil per job
requirements. (McQuay does not supply steam piping
connections.) Install a 1/2", 15-degree swing check vacuum
breaker in the unused condensate return trapping as close as
possible to the coil.The following procedures are
recommended:
7/8-inch OD
copper pipe
CAUTION!
Coil Damage!
Inallsteamcoil installations, the condensate returnconnections
must be at the low point of the coil to ensure condensate flows
freely from the coil at all times. Failure to do so may cause
physical coil damage from water hammer, unequal thermal
stresses,freeze-up and/or corrosion.
Changeover switch Changeover sensor

10 McQuay IM 980-1
Installation
1Vent the vacuum breaker line to atmosphere or connect it
into the return main at the discharge side of the steam
trap.
2Pitch all steam supply and return mains down a
minimum of one inch per ten feet in the direction of flow.
3Do not drain the steam mains or takeoff through the
coils. Drain the mains ahead of the coils through a steam
trap to the return line.
4Overhead returns require one psig of pressure at the
steam trap discharge for each two-feet elevation to
ensure continuous condensate removal.
5Proper steam trap selection and installation is necessary
for satisfactory coil performance and service life. For
installation, use the following steps:
aPosition the steam trap discharge at least 12 inches
below the condensate return connection. This
provides sufficient hydrostatic head pressure to
overcome trap losses and ensure complete condensate
removal.
bMcQuay recommends using flat and thermostatic
traps because of gravity drain and continuous
discharge operation.
cUse float and thermostatic traps with atmospheric-
pressure gravity condensate return, with automatic
controls or where the possibility of low pressure
supply steam exists.
dAlways install strainers as close as possible to the trap
inlet side.
Two-pipe systems with electric heat
The electric heating coil is designed to be the total source of
heat for the unit. If used for auxiliary intermediate season
heating, additional control is required. A second switch or pipe
sensor is required. Contact your McQuay representative for
more information.
To protect the electric heat elements, an automatic and manual
electric heat switch disengages the electric heat to prevent
overheating. For information on resetting the manual switch,
see Electric Heat Over-Temp Reset Button‚ page 17.
External Insulating Requirements
Insulate and vapor-seal surfaces that are colder than the
surrounding air dew point to prevent unplanned condensation.
McQuay recommends field-insulation in the following areas to
prevent potential condensate problems:
•Supply and return water piping connections
•Condensate drain lines and connections
•Fresh air intake duct connections
•Discharge duct connections
•Wall boxes
Electrical Connections
Installation and maintenance must be performed only by
qualified personnel who are familiar with local codes and
regulations, and are experienced with this type of equipment.
Standard Electrical Connection
Field electrical power connections are made in the electrical
junction box, which is mounted to the control box on the side
of the chassis opposite the primary coil piping connections.
See Figure 11. If the unit is equipped with an optional
disconnect switch, it is located in this junction box.
Units with an electric heat option that has the same voltage as
the unit can bring the power conductors into this same junction
box. Units with electric heat that has a different voltage should
bring the electric heat into one of the knockouts on the control
box. See Figure 11.
Low voltage wires should be brought into the conduit located
next to the field electrical power junction box. See Figure 11.
Figure 11: Electrical Power Connections
If electrical wiring or conduit comes through the floor, all
wires or conduit should be sealed at this point. It will prevent
any condensation or water leakage that may occur due to lack
of preventive maintenance.
Note: Wiring coming through the wall should be sealed to stop cold air
infiltration through the wall cavity, which could affect unit
thermostat operation. Wiring coming through the floor should be
sealed to prevent condensation or water leakage from reaching
live wires.
DANGER
Hazardous Voltage!
The installer must determine and follow all applicable codes
and regulations. This equipment presents hazards of
electricity,rotatingparts,sharpedges,heatandweight. Failure
to read and follow instructions can result in property damage,
severe personal injury or death.
Low-voltage
conductors
brought in here
Electric heat
power conductors
brought in here
Unit power
conductors
brought in here

McQuay IM 980-1 11
Installation
Install a strain relief and pass the wires through the strain relief
into the junction box. Make the connections and reinstall the
junction box cover.
Electrical Data
The wiring diagram for the unit is attached to the inside of the
corner panel on cabinet units. It is attached to the front cover
of the unit on hideaway units. See Figure 11. Be sure the
available power is the same voltage and phase as that shown
on the unit serial plate. See Figure 3, page 4 for the location of
the serial plate.
Figure 12: Wiring Diagram Locations
Line and voltage wiring must be done in accordance with local
codes or the National Electrical Code, whichever is applicable.
Apply correct line voltage to the unit. Power to the unit must
be sized correctly. Branch circuit overcurrent protection must
be provided per local codes. See the nameplate for correct
ratings.
All 208-230V single-phase units are factory wired for 230 volt
operation. For 208 V operation the L1 wire connection to the
unit transformer (found in the main control box) must be
changed. The L1 wire must be disconnected from the 230 V
(orange) wire and connected to the 208 V (red) wire. The 230
V wire must then be capped off with a wire nut or male
terminal as appropriate. Please refer to the unit wiring
diagram.
Operating Voltages
Operating voltages are as follows (+/– 10%).
•115/60/1
•208-230/60/1
•265-277/60/1
Note: Voltages listed are to show voltage range. However,
units operating with overvoltage and undervoltage for
extended periods of time will experience premature
component failure.
Thermostat and Controls
Initial Startup
Cleaning & Flushing the Water System
1Prior to first operation of any unit, clean and flush the
water circulating system of all construction dirt and
debris.
2If units are equipped with water shutoff valves, either
electric or pressure operated, connect the supply and
return runouts together at each unit location. This will
prevent the introduction of dirt into the unit. See
Figure 13.
Figure 13: Connections for flushing system piping
Cabinet unit:
Wiring diagram
inside cabinet
corner panel
Hideaway unit:
Wiring diagram on
front panel
DANGER
READ THE INSTRUCTIONS INCLUDED WITH THE
THERMOSTAT/CONTROL CAREFULLY BEFORE
ATTEMPTING TO INSTALL, OPERATE OR SERVICE IT.
Failure to observe safety information and comply with
instructionscould resultinPERSONALINJURY, DEATHAND/
OR PROPERTY DAMAGE.
To avoid electrical shock or damage to equipment, disconnect
power before installing or servicing. Use only wiring with
insulation rated for full thermostat operating voltage. Use
copper wire only. Insulate or wirenut all un-used leads. Any
wiring, including the remote probe,may carry the full operating
voltage of the thermostat.
To avoid potential fire and/ or explosion do not use in
potentially flammable or explosive atmospheres.
Retain the installation instructions for future reference. You
must review your application and national and local codes to
ensure that your installation will be functional and safe.
After wiring and installation are complete, energize the system
and check the operation. Adjust the thermostat as necessary
to complete at least one cycle. Be sure the thermostat and all
other equipment are functioning correctly.
Return Runout
Supply Runout
Mains
Flexible Hose

12 McQuay IM 980-1
Installation
3Fill the system at the city water makeup connection with
all air vents open. After filling, close all air vents.
4Start the main circulator with the pressure reducing valve
open.
5Check vents in sequence to bleed off any trapped air,
ensuring circulation through all components of the
system.
6While circulating water, check and repair any leaks in the
unit and surrounding piping.
7Drains at the lowest point(s) in the system should be
opened for initial flush and blow-down, making sure city
water fill valves are set to make up water at the same
rate.
8Check the pressure gauge at pump suction and manually
adjust the makeup to hold the same positive steady
pressure both before and after opening the drain valves.
9Flush should continue for at least two hours or longer
until the drain water is clean and clear.
10 Shut off the circulator pump and open all drains and
vents to completely drain down the system.
11 Short-circuited supply and return run outs should now be
connected to the unit supply and return connections. Do
not use sealers at the swivel flare connections of hoses.
12 Refill the system with clean water.
13 Test the water using litmus paper for acidity, and treat as
required to leave the water slightly alkaline (pH 7.5 to
8.5).
14 Antifreeze may also be added at this time. Use
commercial grade antifreeze designed for HVAC
systems only. Do not use automotive grade antifreeze.
Antifreeze will have an effect on the performance of the
unit.
15 Once the system has been filled with clean water and
antifreeze (if used), precautions should be taken to
protect the system from dirty water conditions.
Operating Limits
This equipment is designed for indoor installation only.
Sheltered locations such as attics, garages, etc., generally will
not provide sufficient protection against extremes in
temperature and/or humidity, and equipment performance,
reliability, and service life may be adversely affected.
Venting Hydronic Coils
Hydronic coils require a vent, either manual or automatic, to
release air from the unit. Primary coils on all Thinline fan coils
come standard with a coil air vent. It is located on the piping
side of the unit, above the coil connections. See Figure 14.
Secondary coils on ThinLine units are not equipped with an air
vent, but one is included on all factory-supplied valve and
piping packages. It is located on the pipe closest to the outlet
coil connection. See Figure 14.
Perform the following steps to vent both primary and
secondary coils after installing the unit.
1Pressurize the building piping system with water and
vent any trapped air at system vents.
2For units with manual air vents, back the set screw out to
expel air from the unit and then re-tighten the set screw.
3Automotic air vents should require no adjustment for the
coil to vent. However, if the coil does not vent
immediately, unscrew the outer portion of the fitting to
expel air from the port. If debris has become trapped in
the vent, completely remove the outer portion of the
fitting and clean.
Figure 14: Coil Air Vents
CAUTION
Units must be checked for water leaks upon initial water
system startup. Water leaks may be a result of mishandling or
damage during shipping. Failure by the installing contractor to
check for leaks upon start-up of the water system could result
in property damage
IMPORTANT
It is McQuay’s policy not to make recommendations on water
treatment. It is the responsibility of the user to check that the
water supply to the units is free of contaminants or corrosive
agents, chemicals or minerals. The general contractor or
owner should contact a local water treatment company
regarding water treatment. A fouled water system will lead to
premature component failure.
Primary coil
air vent
Reheat coil air vent on
factory-installed package

McQuay IM 980-1 13
Operation and Maintenance
Operation and Maintenance
Controls
A wide variety of control options are available for ThinLine
3G Vertical Fan Coils, both unit-mounted and remote-
mounted. This section provides a brief overview of these
options and their operation. For more complete information,
contact your McQuay representative.
Manual 4-Position Fan Switch
This four-position fan switch (Off, High,
Med, Low) option, shown at the right, is
available remote-mounted. It operates on
low-voltage or line-voltage power and can
be provided with a factory-mounted low-
voltage interface board, which contains
three-24 volt relays with line voltage
contactors and terminal connections. The
transformer is factory-installed and wired.
Sequence of operation
•Off: Fan is turned off. The motorized fresh-air damper, when
supplied, is closed (see Fresh Air Damper‚ page 16).
•High, Medium, Low: Fan runs continuously at the selected
speed. The two-position, motorized fresh-air damper, when
supplied, is opened.
Unit-Mounted, Mechanical Thermostat With
4-Position Fan Switch
The unit-mounted
option, shown at the
right, combines the
four-positionfanswitch
with a mechanical
thermostat. For two-
pipe systems with a
factory installed valve
package, it can be
provided with a manual
switch (shown in
picture to the right) to
change from heating to
cooling. Alternatively, the changeover can be automatic.
Sequence of operation
•Fan Switch
•Off: Fan is turned off. The two-position, motorized
fresh-air damper, when supplied, is closed (see Fresh Air
Damper‚ page 16).
•High, Medium, Low: Fan runs continuously at the
selected speed. The two-position, motorized fresh-air
damper, when supplied, is opened.
•Thermostat
• Cycles the valve(s) open or closed on demand based on
occupant-desired level.
•Changeover Switch: With a manual switch, the user selects
whether heating or cooling is desired. With automatic
changeover, a pipe sensor works with the thermostat to
operate the heating or cooling valve.
•Heating: Opens the valve when the temperature is below
the setpoint.
•Cool: Opens the valve when the temperature is above the
setpoint.
Digital Thermostats
McQuay offers a broad
range of unit-mounted and
remote, wall-mounted
digital thermostats with
the capabililty to control
On-Off, 3-wire and
proportional modulating
valves, and Normally
Closed or Normally Open
actuator valves. For more
information, refer to the
McQuay publication ED 18513-1 and ED 18527.
MT155 Thermostat
For more details refer to page 47. The MT155 series thermostat
provides on-off control for low-voltage or line-voltage valves
and fan motors. This thermostat is designed as a remote-mount
with connection to the LV interface board mounted on the fan
coil unit. Options include manual or automatic changeover and
three-speed fan control for continuous or cycling fan operation.
The thermostat may be mounted on units already at the job site.
Each unit should be equipped with an LV Interface Board, if
not, a Controls Mounting Kit PN910112080 needs to be
ordered. For field installation instructions of the MT155 on a
unit, refer to page 45.
Figure 15: MT155 Thermostats
Three standard control options are available:
•On-Off fan cycle operation only: The thermostat cycles the
fan from the manually selected fan speed (high, medium or
low) to off.
•Continuous fan and On-Off valve cycle operation: The
thermostat cycles the valves on and off. The fan runs
continuously at the manually selected fan speed.

14 McQuay IM 980-1
Operation and Maintenance
•On-Off fan and On-Off valve cycle operation: The
thermostat cycles the fan from the manually selected fan
speed to off and it cycles the valves on and off.
When the system switch is in the OFF position, the fan coil
system including the fan is shut off.
TA155: A HEAT-OFF-COOL system switch manually selects
heating or cooling mode. In the HEAT position, only the heat
output cycles with demand. In the COOL position, only the
cool output cycles with demand. In the OFF position, heating
and cooling outputs are off. Units with a two position system
switch or without a system switch must use a load transfer
switch when both heating and cooling outputs are used. This
prevents control failure and equipment damage caused by
direct cycling between loads.
TB155: An ON-OFF system switch enables auto-changeover
of heating and cooling modes. In the ON position the
thermostat activates heating or cooling outputs dependant
upon the relationship between set point and ambient
temperature. Heat on to cool on dead band is 4°F. In the OFF
position, heating and cooling outputs are off. Units without a
system switch cycle between heating and cooling with a 4°F
dead band.
FAN: Some units have a switch for manual selection of fan
speed. On these units fan operation is either internally wired
for fan continuous operation or is dependant upon connection
to the fan supply input . When internally wired for fan
continuous operation, the fan will be off when the system
switch is off. When dependant upon external connections the
fan may not be off with the system switch in the off position.
The fan supply input is switched to fan speed outputs (HI-
MED-LO).
MT158 and MT168 Thermostat-Controllers with
Digital Display
For more details refer to page 51, 55 or 59. Series MT158 and
MT168 microprocessor-based thermostat-controllers combine
a proportional integral control algorithm with adaptive logic.
They may be unit-mounted or remote-wall mounted.
Figure 16: MT158 and MT168 Thermostats
Heating and cooling outputs for the MT158 are individually
configurable for three-wire floating control valves or On/Off
valves in the Normally Open or Normally Closed modes.
Heating and cooling outputs for the MT168 provide 0-10 Vdc
or 4-20 mA for proportional modulating valve control. The
integrated, three-speed fan control switch is line voltage to
allow direct connection to the fan motors. Manual or automatic
changeover is provided with remote setback capability from a
time clock or facility management system. Features include a
Fahrenheit or Celsius digital display and a built-in purge cycle
which assists the controller to determine if the system is
supplying hot water or cooling.
Two standard control options are available:
•Continuous fan and modulating (or On-Off) valve
operation: The fan runs continuously at the manually
selected fan speed (high, medium or low). The controller
modulates the valves or, on the MT158, dip-switches can be
set to cycle the valves on and off.
•On-Off fan cycle operation and modulating (or On-Off)
valve operation: The controller cycles the fan from the
manually selected fan speed to off. The controller modulates
the valves or, on the MT158, dip-switches can be set to cycle
the valves on and off.
T170 Thermostat with Digital Display
Two thermostats are offered for remote installation only:
TA170 for three-speed fan control and TB170 for staged fan
operation. Both thermostats are used for On-Off control of
low- or line-voltage valves with auto changeover. Detailed
installation instructions and modes of operation can be found
in page 63.
Figure 17: T170 Thermostat with Digital Display

McQuay IM 980-1 15
Operation and Maintenance
Low-Voltage (LV) Interface Board
The low-voltage interface board is used with any remote (wall
mounted) McQuay thermostat or control. It can also be used in
conjunction with a controller of a building automation system
(BAS) control where low voltage is needed to operate the fan
coil. It is located in the control box for the unit (see Figure 11,
page 10).
The LV interface board includes:
•Three 24-volt relays with line-voltage contactors to operate
the fan motor speeds.
•Terminal connections for interfacing to:
• An optional remote-mounted thermostat.
• Low-voltage actuators for heating and cooling valves.
• A return air sensor.
• A pipe temperature sensor for changeover from heating
to cooling on two-pipe systems.
•A factory-wired and installed transformer.
See Figure 18 for a list of connecting points to the board. For
additional wiring information, see the typical wiring diagram
Figure 37, page 28 or the unit’s wiring diagram, which is
attached to the corner panel on cabinet units and to the chassis
front cover on hideaway units. (see Figure 12, page 11).
For instructions on field-mount MT155 thermostats on units
supplied with LV Interface boards (a typical arrangement for a
5-day Quick Ship Program), refer to page 45.
Figure 18: LV Interface Board 24 VAC connections
Low Voltage Fan motor control
Low-voltage valve actuators
Room air or return air temperature sensor
Pipe temperature sensor
Condensate overflow sensor
Remote thermostat 24 VAC power

16 McQuay IM 980-1
Operation and Maintenance
Accessories
Fresh Air Damper
The fresh air damper kit provides up to 25% outside air to the
unit heater. It consists of an intake with damper blade and
insect screen. The damper may be manually controlled through
the return air opening or with an optional field-installed
damper motor. For detailed installation information, refer to
page 37.
Operation
To open the damper, reach under the unit and pull the damper
handle toward you. To close, push the damper away from you.
See Figure 19.
Figure 19: Opening and Closing the Damper
If the damper is difficult to open or moves too freely, you can
adjust the tension by tightening or loosening the nuts on its
pivot axis. See Figure 20.
Figure 20: Adjusting Damper Tension
Cold Weather Operation
Unit heaters may experience erratic operation during cold
ambient conditions with the outside air damper in the open
position.
Fresh Air Damper Motor Kit (Low Voltage)
This damper motor kit is for field installation with the fresh air
damper kit. The damper kit must be ordered separately. For
detailed installation instructions, refer to page 39, which is
supplied with the damper motor kit. Under most control
schemes, the damper motor is set up to open the damper
automatically whenever the unit fan is in operation.
Figure 21: Damper Motor Kit Installed in Unit
Condensate Overflow Detection Device
The condensate overflow detection device is a factory-installed
option on fan coils. This device has a condensate overflow
floater with dry contacts and is connected to the LV interface
board. See Figure 22.
If you suspect it is not working properly, check to be sure that
the float is installed straight up with the proper elevation. See
Accessing/removing the main drain pan and motor assembly‚
page 19 for instructions on removing the main drain pan to
access the device.
The condensate overflow switch needs to be wired to the
proper controller (T170 for example) to shut off the fan if
water is present in the drain pan.
Figure 22: Condensate Overflow Switch Installation
To open damper, reach under the unit
and pull the damper handle toward you
To adjust damper tension, loosen or
tighten nuts on each end of damper axis.

McQuay IM 980-1 17
Operation and Maintenance
Leveling Legs Option
Field or factory-installed kits are available with 0” to 1"
adjustment for positive leveling of floor-mounted units.
Height Adjustment
To adjust the height of a leveling leg:
1Loosen the locking nut on the leveling leg bolt with a
9/16-inch wrench.
2Turn the leveling leg bolt clockwise to lower the unit or
counterclockwise to raise it.
3When you are finished adjusting the height, hold the
leveling leg bolt in place and draw the locking nut up
tight against the mounting bracket.
Figure 23: Leveling Legs Adjustment
Cabinet Rear Extension Kit
The field-installed cabinet rear extension option may be
utilized to place the fan coil farther out from the wall than the
standard unit allows. Refer to page 41 for more details.
Figure 24: Cabinet Rear Extension Kit
Electric Heat Over-Temp Reset Button
The elecric heat options comes with two over-temperature
switches. The first resets automatically when the over-
temperature condition no longer exists. The second, backup
switch must be reset manually.
Note: The need to reset the manual switch may indicate that
there are improperly functioning system components. If
the switch trips again, contact McQuay Factory Service
for help in diagnosing the cause.
To reset the manual switch, carry out the following steps:
1Disconnect all power to the unit. Verify the power has
been disconnected.
2Remove the main drain pan and motor assembly from
the unit (see Accessing/removing the main drain pan and
motor assembly‚ page 19).
3Access and push in the red reset button. See Figure 25.
Figure 25: Electric Heat Over-Temp Reset Button Location
4Reinstall the drain pan and motor assembly.
5Reconnect the power.
To adjust height, loosen the locking nut
with a 9/16” wrench. Then, turn the
leveling leg bolt head clockwise to raise
the unit, or counterclockwise to lower it.
Cabinet
Rear
Extension
Vertical
Fan Coil
Unit
DANGER
Personal Injury Hazard.
Power supply can cause electrical shock. Always disconnect
power to unit before servicing.
Push the red reset button

18 McQuay IM 980-1
Operation and Maintenance
Key-lock Access Door Kit
The key-lock access door kit (see Figure 26) can be installed
on ThinLine 3G cabinet units to prevent access to unit
controls. For detailed installation information, refer to page 43.
Figure 26: Key-Lock Access Door Kit
General Maintenance
Normal maintenance on all units is generally limited to filter
changes and cleaning the condensate drain pans. Units are
provided with permanently lubricated motors and require no
oiling even though oil caps may be provided.
Record performance measurements of volts, amps, and water
temperature differences (both heating and cooling). A
comparison of logged data with start-up and other annual data
is useful as an indicator of general equipment condition.
Filter Changes
Filter changes are required at regular intervals. The time
period between changes will depend upon the project
requirements. Some applications, such as motels, produce a lot
of lint from carpeting and linen changes, and will require more
frequent filter changes. Check filters at 60-day intervals for the
first year until experience is acquired. If light cannot be seen
through the filter when held up to sunlight or a bright light, it
should be changed. A more critical standard may be desirable.
Filters can be removed without removing any panels. See
Figure 27. However, if the unit is equipped with a return air
grille, this must first be removed to access the filter. To remove
the filter:
1Slide your hands under the front opening on the bottom
of the unit and feel for the filter above.
2Slide your fingers along the bottom of the filter until they
reach the rear paperboard edge.
3Push the paperboard edge backward about a half-inch
until the front edge of the filter drops down.
4Remove the filter from under the unit.
To install a new filter:
1Slide the filter under the unit and tilt its rear 0edge
upward and into the pocket at the rear of the filter
housing.
2Push the front edge of the filter backward until it clears
the front lip on the filter housing, then push it up and into
place.
Figure 27: Filter Removal
Condensate Drain Pans
The main and secondary condensate drain pans should be
checked annually and cleaned and flushed as required. See
Figure 28.
Figure 28: Drain Pan Locations
Accessing the secondary drain pan
To access the secondary drain pan, remove the corner panel
from the side of the unit where the main piping connections
are made (this is opposite the side where the control access
panel is located on units with unit-mounted controls. See
Figure 5, page 6 for a description of how to remove it.
Push filter
backward
and tilt
down front
edge to
remove
Main Drain Pan
Secondary
Drain Pan
Remove screws and
slide forward to access pan

McQuay IM 980-1 19
Operation and Maintenance
Accessing/removing the main drain pan and motor
assembly
The main drain pan is housed in the top of the unit’s fan deck.
Both the fan deck and the main condensate drain pan are easily
removed for access and cleaning as follows.
1Disconnect electrical power to the unit.
2Remove the two screws that attach the center panel of
the unit to the base ( see Figure 5, page 6).
3Lift the center panel upward and off the unit.
4Pull the main condensate drain line out of the side of the
chassis where it flows into the secondary drain pan.
5Disconnect the fan motor wiring harness by removing
the plug where it attaches to the connector on the side of
the chassis. See Figure 29.
Note: Push the tabs inward on the sides of the plug to free
it from the connector base.
Figure 29: Motor Connector Location
6Remove the screws that attach the fan deck to the unit
chassis. See Figure 28
7Firmly grasp the fan deck, then slide it towards you and
out of the unit.
8The main condensate drain pan sits atop the fan deck and
is now easily accessed for cleaning.
9To reinstall, follow these steps in reverse order.

20 McQuay IM 980-1
Physical Data
Physical Data
Unit Data
Table 1: Unit Data
Shipping Weights
Table 2: Approximate Shipping Weights - lbs (kg)*
02 03 04 06 08 10 12
Primary Coil Data
Face Area, ft2(cm2) 0.74 (685) 1.08 (1004) 1.43 (1323) 2.11 (1962) 2.46 (2281) 3.14 (2917) 3.83 (3559)
Fins/inch (cm) 12 [4.7] 12 [4.7] 12 [4.7] 12 [4.7] 12 [4.7] 12 [4.7] 12 [4.7]
Coil Connection 1/2" Nominal copper female (5/8" OD)
Coil Dimensions
2-Row
L x D x H, in (cm) 11.8 x 1.7 x 9 (30.0x4.4x22.9) 17.3 x 1.7 x 9 (43.9x4.4x22.9) 22.8 x 1.7 x 9 (57.9x4.4x22.9) 33.8 x 1.7 x 9 (85.9x4.4x22.9) 39.3x 1.7 x 9 (99.8x4.4x22.9) 50.2 x 1.7 x 9 (127.6x4.4x22.9) 61.3 x 1.7 x 9 (155.7x4.4x22.9)
3-Row
L x D x H, in (cm) 11.8 x 2.6 x 9 (30x6.6x22.9) 17.3 x 2.6 x 9 (43.9x6.6x22.9) 22.8 x 2.6 x 9 (57.9x6.6x22.9) 33.8 x 2.6 x 9 (85.9x6.6x22.9) 39.3 x 2.6 x 9 (99.8x6.6x22.9) 50.2 x 2.6 x 9 (127.6x6.6x22.9) 61.3 x 2.6 x 9 (155.7x6.6x22.9)
4-Row
L x D x H, in (cm) 11.8 x 3.5 x 9 (30.0x8.8x22.9) 17.3 x 3.5 x 9 (43.9x8.8x22.9) 22.8 x 3.5 x 9 (57.9x8.8x22.9) 33.8 x 3.5 x 9 (85.9x8.8x22.9) 39.3 x 3.5 x 9 (99.8x8.8x22.9) 50.2 x 3.5 x 9 (127.6x8.8x22.9) 61.3 x 3.5 x 9 (155.7x8.8x22.9)
Coil Volume, Gal (Liters)
2-Row 0.15 (0.6) 0.19 (0.7) 0.24 (0.9) 0.32 (1.2) 0.37 (1.4) 0.46 (1.7) 0.55 (2.1)
3-Row 0.20 (0.7) 0.26 (1.0) 0.32 (1.2) 0.45 (1.7) 0.52 (2.0) 0.64 (2.4) 0.77 (2.9)
4-Row 0.26 (1.0) 0.34 (1.3) 0.43 (1.6) 0.61 (2.3) 0.70 (2.6) 0.87 (3.3) 1.05 (4.0)
Reheat Coil Data: 1-Row, Hot Water or Steam
Face Area, ft2(cm2) 0.49 (456) 0.72 (669) 0.95 (882) 1.41 (1308) 1.64 (1521) 2.09 (1944) 2.55 (2372)
Fins/inch (cm) 12 [4.7] 12 [4.7] 12 [4.7] 12 [4.7] 12 [4.7] 12 [4.7] 12 [4.7]
Coil Connection 1/2" Nominal copper female (5/8" OD)
L x D x H, in (cm) 11.8 x 0.9 x 6
(30.0x2.2x15.2) 17.3 x 0.9 x 6 (43.9x2.2x15.2) 22.8 x 0.9 x 6 (57.9x2.2x15.2) 33.8 x 0.9 x 6 (85.9x2.2x15.2) 39.3 x 0.9 x 6 (99.8x2.2x15.2) 50.2 x 0.9 x 6 (127.6x2.2x15.2) 61.3 x 0.9 x 6 (155.7x2.2x15.2)
Volume, Gal (Liters) 0.04 (0.1) 0.05 (0.2) 0.07 (0.3) 0.10 (0.4) 0.11 (0.4) 0.14 (0.5) 0.17 (0.7)
Preheat Coil Data, 2-Row, Hot Water or Steam
Hot Water or Steam
Face Area, ft2(cm2) 0.49 (456) 0.72 (669) 0.95 (882) 1.41 (1308) 1.64 (1521) 2.09 (1944) 2.55 (2372)
Fins/inch (cm) 12 [4.7] 12 [4.7] 12 [4.7] 12 [4.7] 12 [4.7] 12 [4.7] 12 [4.7]
Coil Connection 1/2" Nominal copper female (5/8" OD)
L x D x H, in. (cm) 11.8 x 1.7 x 6
(30.0x4.4x15.2) 17.3 x1.7 x 6 (43.9x4.4x15.2) 22.8 x 1.7 x 6 (57.9x4.4x15.2) 33.8 x 1.7 x 6 (85.9x4.4x15.2) 39.3 x 1.7 x 6 (99.8x4.4x15.2) 50.2 x 1.7 x 6 (127.6x4.4x15.2) 61.3 x 1.7 x 6 (155.7x4.4x15.2)
Volume, Gal (Liters) 0.08 (0.3) 0.10 (0.4) 0.13 (0.5) 0.19 (0.7) 0.22 (0.8) 0.29 (1.1) 0.35 (1.3)
Fan/Motor Data
Fan Quantity 1 1 2 2 3 4 4
Size, Dia” x W” (cm) 6.26 x 6.3
(15.9 x 16) 7.95 x 6.3 (20 x 16) 6.26 x 6.3 (15.9 x 16) 7.95 x 6.3 (20 x 16) 6.26 x 6.3 (15.9 x 16) 6.26 x 6.3 (15.9 x 16) 7.95 x 6.3 (20 x 16)
Motor Quantity 1 1 1 1 2 2 2
Filter Data
Part Number 668332901 668332902 668332903 668332907 668332905 668332906 668332904
1” (25.4 cm) Media TA only TA only TA only TA only TA only TA only TA only
Quantity 1 1 1 1 2 2 2
L x D x H, in. (cm) 16 x 8.75 x 1
(40.6 x 22 x 2.5) 21.5 x 8.75 x 1 (54.6 x 22 x 2.5) 27 x 8.75 x 1 68.5 x 22 x 2.5 38 x 8.75 x 1 (96.5 x 22 x 2.5) 21.7 x 8.75 x 1 (56.1 x 22 x 2.5) 27.2 x 8.75 x 1 (69.0 x 22 x 2.5) 32.7 x 8.75 x 1 (83.1 x 22 x 2.5)
Unit Type Unit Size
S02S03S04S06S08S10S12
FCVC,FCVS 84 (38) 95 (43) 108 (49) 131 (60) 152 (69) 177 (80) 202 (92)
FCVH 55 (25) 63 (29) 74 (34) 91 (41) 110 (50) 129 (59) 149 (68)
Note: *Approximate shipping weights do not include valve packages, hot water coils, electric heaters or other options.