American Standard WK 100 Series Owner's manual

1
WK-IOM-2
Library Service Literature
Product Section Unitary
Product Rooftop Lt. Comm.
Model WK
Literature Type Installation/ Oper/ Maint
Sequence 2
Date November 2000
File No. SV-UN-RT-WK-IOM-2 11/00
Supersedes New
Packaged Heat Pump
100 - 200 Models
INSTALLATION
OPERATION
MAINTENANCE
Customer Property — Contains wiring, service,
and operation information. Please retain.
Models: (50 Hz)
WK*100-125
WK*155-200
IMPORTANT NOTE: All phases of this installation must comply with the NATIONAL, STATE & LOCAL CODES.
These units are equipped with an electronic unit control processor, (UCP) that provides service functions which are
significantly different from conventional units. Refer to the TEST MODES and START-UP PROCEDURES before
attempting to operate or perform maintenance on this unit.
Since the manufacturer has a policy of continuous product
improvement, it reserves the right to change specifications and design
without notice. The installation and servicing of the equipment referred
to in this booklet should be done by qualified, experienced technicians.
© American Standard Inc. 2000

2
Read this manual carefully before attempting to install, oper-
ate or perform maintenance on this unit. Installation and main-
tenance must be performed by qualified service technicians
except where noted.
Bodily injury can result
from high voltage electrical components and fast
moving fan drives. For protection from these inherent
hazards during installation and servicing, the
electrical supply must be turned off. If operating
checks must be performed with the unit operating, it
is the technician’s responsibility to recognize these
hazards and proceed safely.
All power legs to the
electrical components may not be broken by
contactors. See the wiring diagram on the unit control
box cover.
Before starting the compressor, the crankcase heaters should
be energized for eight hours.
Attaching Downflow Ductwork to Roof Curb ............. 9
Filter Installation ........................................................ 9
Evaporator Fan Adjustment ....................................... 9
Interconnecting Diagram ......................................... 12
Wire Connection Guide ........................................... 14
Pre-Start Quick Check List ...................................... 14
Power-up Initialization ............................................. 15
Unitary Control Processor (UCP) ............................ 15
Switch Settings for Cycle Timing ............................. 15
Defrost Module Test & Operation ............................ 16
Final Installation Checklist ....................................... 16
Inspection .................................................................. 2
Module Names .......................................................... 3
Unit Features ............................................................. 3
ZSM Mode ................................................................. 3
Auto Test Mode.......................................................... 4
Resistance Test Mode ............................................... 4
Unit Dimensions ........................................................ 5
Curb Dimensions ....................................................... 6
Installation ................................................................. 7
Unit Support .............................................................. 7
Location and Clearances........................................... 7
Placing and Rigging .................................................. 7
Table of Contents
Note: “Warnings” and “Cautions” appear at
appropriate places in this manual. Your personal
safety and the proper operation of this machine
require that you follow them carefully. The
manufacturer assumes no liability for installations or
servicing performed by unqualified personnel.
Inspection
1. Check for damage after unit is unloaded. Report promptly,
to the carrier, any damage found to unit. Do not drop unit.
2. Check unit nameplate to determine if unit is correct for ap-
plication intended. Power supply must be adequate for the unit
and all accessories.
3. Check to be sure the refrigerant charge has been retained
during shipment. Access to 1/4" flare pressure taps may be
gained by removing compressor compartment access panel.

3
MODULE NAMES
UCP -Unitary Control Processor (standard component)
This is the heart of the system. The computer program
resides in this module. The minimum configuration will
include the UCP and one of the zone sensor modules
ZSM -Zone Sensor Module (accessory component)
Replaces thermostat, provides operator controls and the
zone temperature sensor for the UCP.Acomplete line of
ZSMs is available with various combinations of features.
A zone sensor module, or a CTI and generic control is
required for each system.
UEM - Unitary Economizer Module (standard component
on economizer accessory). This module provides the
hardware necessary to connect the economizer
accessory to the UCP.
TCI - Communication Interface. This interface is required
to connect the system to an ICS BUILDING
MANAGEMENT, i.e. - Tracker or Tracer. system.
CTI - Conventional Thermostat Interface (accessory
component.) This module can be used in special
applications that require the installation of select electro-
mechanical thermostats to interface with the UCP, instead
of using a zone sensor module (ZSM)
UNIT FEATURES
Self-test/Auto-configuration
At power-up, the system will perform a series of tests to verify
correct operation and configure itself automatically, based on
the unit wiring harness.
Cooling Minimum ON/OFF times
To enhance compressor reliability, a minimum of 3 minutes
ON/OFF time has been implemented in the software. Any time
power is applied or re-applied (e.g. after a power failure), the 3
minutes minimum OFF time is enforced to prevent short cy-
cling a compressor.
Lead-Lag (Cooling Mode Only)
A selectable configuration within the UCP which alternates the
starting of the compressors between the two refrigeration cir-
cuits. To enable the Lead/Lag function, cut wire 52F (PR)
which is connected to terminal J1-7 at the UCP. Refer to the
unit wiring diagram. Each time the request for cooling is satis-
fied, the designated lead compressor switches. Upon Power-
up Initialization, the control will default to the number one com-
pressor. When a Conventional Thermostat Interface (CTI) is
used, Lead/Lag is functional except during the test mode.
Zone Temperature Sensor
The zone temperature sensor provides the zone temperature
sensing function to the UCP.
ZSM MODE
HEAT - Heat functions only enabled.
AUTO - Auto-changeover between Cooling mode and
Heating mode as required by zone load (on some
models).
OFF - No heating or cooling functions
COOL - Cooling functions only, including economizer function
enabled.
FAN SETTINGS
FAN AUTO - Fan is enabled only when heating or cool
ing functions are required.
FAN ON - Fan is enabled at all times. This setting is
used when air circulation is required.
Option Remote Panel Zone Sensors
Indicator Lights
SYS-ON
Indicates that power is applied to the unit and the UCP is func-
tioning correctly. This indicator will flash at a 1 second rate to
indicate operation of one of the test modes.
HEAT
Indicates that at least one stage of heat is ON. This indicator
will flash at a 1 second rate to indicate a heat failure .
COOL
Indicates that cooling is active. This could be economizing
and/or compressor cooling. This indicator will flash at a 1 sec-
ond rate to indicate a cool failure. Sources of cool failure in-
clude high pressure controls if present and zone sensor fail-
ures.
SERVICE
Indicates that a problem exists in the supply air stream. Could
be dirty filters, broken drive belt or other functions depending
on what sensors or switches are installed on the fan/filter
status input.

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Test Mode Table
Step Mode Fan Econ C1 C2 Heat 1 Heat 2 Heat 3 Defrost Em Heat
1 Fan On On Min Off Off Off Off Off Off Off
2* Econ On Open Off Off Off Off Off Off Off
3 Cool 1 On Min On Off Off Off Off Off Off
4 Cool 2 On Min On On Off Off Off Off Off
5 Heat1 On Min On On On Off Off Off Off
6* Heat 2 On Min On On On On Off Off Off
7* Heat 3 On Min On On On On On Off Off
8** Defrost On Min On On Off On On On Off
9** Em Heat On Min Off Off Off On On Off On
* With Optional Accessory ** With Heat Pump
Note: Steps for optional accessories and modes not present in unit, will be skipped.
Resistance Valves Chart
STEP MODE Ohms
1 FAN ON 2.2K
2* ECONOMIZER 3.3K
3 COOL 1 4.7K
4 COOL 2 6.8K
5 HEAT 1 10K
6* HEAT 2 15K * With Optional Accessory
7* HEAT 3 22K ** With Heat Pumps
8** DEFROST 33K Note: Steps 7,8 & 9 are not applicable
9** EM HEAT 47K on Electric/Electric or Gas Units
TEST MODE PROCEDURE
Operating the unit from the roof using the test mode.
When operating the unit in
the test mode, the evaporator access panel and the
control box cover, must be closed. Failure to ensure
that the evaporator access panel and control box
cover is in place could result in severe personal
injury or death
The Unitary Control Processor (UCP) has a red indicator light
in the lower left corner. When power is applied to the unit the
light will glow if the UCP is functioning correctly. If the system
is placed in the test mode the light will blink continuously.
Note: The control box cover has a small peep hole,
located in the lower left hand corner. The red
indicator light on the UCP can be seen through this
peep hole. Do not remove the control box cover while
the unit power is connected.
Step Test Mode
The step test mode is initiated by shorting across the “TEST”
terminals, marked test 1 and test 2 on the unit’s low voltage
terminal strip (LTB), for two (2) to three (3) seconds and then
removing the short.
When the test mode is initiated, the light on the UCP will blink
and the system will begin the first test step, and turn on the in-
door fan. (See test mode table)
To continue to the next step, reapply the short across the test
terminals for 2 to 3 seconds.
The unit may be left in any test step for up to one hour. If al-
lowed to remain in any test step for more than one hour, the
test mode will terminate and control will revert to the zone sen-
sor. As you continue to apply and remove the short across the
test terminals, the unit will move through the steps according
to the table below.
To terminate the test mode, cycle the unit power at the unit
disconnect or continue stepping through the modes until the
UCP’s indicator light glows constantly.
Auto Test Mode
—The auto test mode is initiated by installing a jumper be-
tween terminals marked TEST 1 and TEST 2 on the LTB.
The unit will start in step 1 and cycle through the test steps
one time, changing every 30 seconds.
—When the test mode is initiated, the light on the UCP will
blink and the system will begin the first test step, and turn
on the indoor fan. (See test mode table)
—At the end of the auto test mode, the indicator light will glow
constantly and control will revert to the zone sensor.
—The unit can be left in any one of the test steps, by remov-
ing the jumper. It will remain in this step for up to one hour.
If allowed to remain in any test step for more than one hour,
the test mode will terminate and control will revert to the
zone sensor.
— To terminate the test mode, cycle the unit power at the unit
disconnect.
Resistance Test Mode
The resistance test mode is Initiated by applying the appropri-
ate resistance value across the “Test” terminals marked TEST
1 and TEST 2 on the LTB.
—When the test mode is initiated, the light on the UCP will
blink and the system will begin the test step selected by the
resistance being applied across the test terminals. (See test
mode table)
—The resistance values are indicated in the Resistance Value
Chart below.
—After selecting the desired test step, and applying the appro-
priate resistance across the test terminals, the unit will start.
—The unit can be left in this step for up to one hour. If allowed
to remain in any test step for more than one hour, the test
mode will terminate and control will revert to the zone sensor.
—To terminate the test mode, remove the resistance, and
cycle the unit power at the unit disconnect.

5
HORIZONTAL UNIT
REAR VIEW SHOWING DUCT OPENINGS
FOR HORIZONTAL AIR FLOW - mm
UNITS A B C D E F
WKH100 571 457 437 51 100 1053
WKH125, 155 673 497 624 51 100 1080
WKH200 673 611 700 51 100 1180
DOWNFLOW UNIT
TOP VIEW SHOWING DUCT OPENINGS IN THE BASE - mm
UNITS A B C D E
WKD100 570 368 449 1312 1199
WKD125, 155 672 572 475 1586 1389
WKD200 672 730 506 1938 1745
Dimensional Data
Unit Dimensions - mm
Units ABCDEFGHJK
WK* 100 1608 2380 20 1245 726 56 213 1000 173 51
WK* 125, 155 1798 2710 20 1273 744 68 213 1229 168 51
WK* 200 2154 3107 20 1372 843 69 226 1422 173 76
* Downflow or Horizontal

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Figure 1 - Curb Dimensions - mm
UNITS A B C D E F G H J K L M N P
WKD100 1502 1408 46 486 251 622 2259 1509 2267 51 357 25 205 1205
WKD125, 155 1692 1600 46 530 435 724 2588 1702 2597 51 357 25 191 1410
WKD200 2048 1956 46 565 591 725 2969 2057 2977 51 357 25 191 1765

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INSTALLATION
Location and Recommendations
Unit Support
If unit is to be roof mounted check building codes for weight
distribution requirements. Refer to accessory roof curb mount-
ing instructions. Check unit nameplate for supply voltage re-
quired. Determine if adequate electrical power is available.
Refer to specification sheet.
Location and Clearances
Installation of unit should conform to local and national build-
ing codes.
Select a location that will permit unobstructed airflow into the
condenser coil and away from the fan discharge. Suggested
airflow clearances and service clearances are given in
Figure 1.
Placing and Rigging
Note : Before attempting to rig the unit, remove the
fork lift pockets located on the condenser end of the
unit.
Rig the unit using either belt or cable slings. The sling eyelet
must be placed through the lifting holes in the base rail of the
unit. The point where the slings meet the lifting eyelet should
be at least 6 feet above the unit. Use spreader bars to prevent
excessive pressure on the top of the unit during lifting. Figure
2 shows the unit center of gravity.
IMPORTANT: The use of “spreader bars” is required
when hoisting the unit (prevents damage to sides and
top). Top crating can be used as spreader bars.
Figure 2
Mounting Unit on Roof
Downflow units should be mounted on a roof curb when pos-
sible. When installing the unit on the roof curb, follow the in-
stallation instructions accompanying the roof curb kit. On new
roofs, the curb should be welded directly to the roof deck. For
existing construction, nailers must be installed under the curb
if welding is not possible. Be sure to attach the downflow
ductwork to the curb before setting unit in place. See Figure
3A or 3B. Refer to the curb installation instructions to insure
the unit will be level.
When installing the unit, it must be level to insure proper con-
densate flow from the unit drain pan. The maximum pitch of
the unit down from the condensate drain of the unit is 0.5 mm
per meter (1/16 inch per foot).
Slab Mount
For ground level installation, the unit base should be ad-
equately supported and hold the unit near level. The installa-
tion must meet the guidelines set forth in local codes.
Table 1
Corner weights & Center of Gravity
Unit Net
DimensionsWeightABCDLengthWidth
WK*100B 536 183 140 92 120 1041 635
WK*125B 625 218 159 105 144 1143 711
WK*155B 642 228 162 105 147 1143 711
WK*200B 871 291 226 155 199 1346 889
* Downflow or Horizontal
Corner Weights (kg)
(See Note 1) Center of Gravity (mm)

8
Note: Corner weights are given for information only. Unit is to be supported continuously by curb or equivalent
frame support.
Duct Dimensions - mm
UNITS ABCDEFG
WK*100 1318 411 1130 567 25 357 189
WK*125, 155 1510 454 1334 643 25 357 189
WK*200 1865 491 1689 668 25 357 189
* G Dimension represents the distance from the top fo the curb to the duct flange.
Figure 3

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Figure 4
Filter Installation
To gain access to filters, remove the evaporator fan access
panel. Each unit ships with 2 inch filters. Number and size of fil-
ters is determined by size and configuration of the unit. Refer to
the unit “Service Facts” for filter requirements.
Note: On WKD100 and WKH200 units, there is an
installation instruction label on the end of the filter rack
which provides instructions on how to replace the top
filters.
Evaporator Fan Adjustment
Use the following procedure to determine the proper adjustment
of the evaporator fan sheaves for a specific application.
1. Determine total system external static pressure (in inches wa-
ter column) with accessories installed. To accomplish this:
a. Obtain the design airflow rate and the design external
static pressure drop through the distribution system. Your
sales representative or the design engineer can provide you
with these values.
b. Using the table from unit Service Facts, add static
pressure drop of the accessories installed on the unit.
c. Add the total accessory static pressure drop (from step
1b) to the design external static pressure. The sum of these
two values is the total system external static pressure.
2 . Use the table(s) in the Service Facts to find the external static
pressure (in inches water column) that most closely approxi-
mates total system external static pressure. Then locate the
appropriate airflow rate (in m3/n (cfm) for your unit. The value
obtained represents the Kw brake horsepower for the evapo-
rator fan motor and the fan RPM.
Important: Fan Kw Break Horsepower (BHP) listed in
the Table is the percentage range of nameplate
amperage the motors will safely work within before and
oversized motor is required.
3. Adjust the variable pitch pulley to increase or decrease the
fan RPM as required. See Figure 5.
Ductwork
Attaching Downflow Ductwork to Roof Curb
Supply and return openings have curb flanges provided for
easy duct installation.
Note: Ductwork sleeves must be attached to the
curb flanges before the unit is set into place. See
Figure 3A and 3B for duct connections and
dimensions.
Guidelines for ductwork construction:
— Connections to the unit should be made with three-inch
canvas connectors to minimize noise and vibration trans-
mission.
— Elbows with turning vanes or splitters are recommended to
minimize air noise and resistance.
— The first elbow in the ductwork leaving the unit should be
no closer than 610 mm (two feet) from the unit, to mini-
mize noise and resistance.
Attaching Horizontal Ductwork to Unit
— All conditioned air ductwork should be insulated to mini-
mize heating and cooling duct losses. Use minimum of 50
mm (2") of insulation with a vapor barrier. The outside
ductwork must be weather proofed between the unit and
the building.
— When attaching ductwork to a horizontal unit, provide a
flexible water tight connection to prevent noise transmis-
sion from the unit to the ducts.
Note: Do not draw the canvas connectors taut
between the unit and ducts. See dimensional data
for duct connections.
Condensate Drain Piping
A 1 inch NPT female condensate drain connection is pro-
vided on all units.
Follow local codes and standard piping practices when run-
ning the drain line. Install a trap and be sure to fill with water
before starting the unit. Pitch the line downward, away from
the unit; avoid long, level, horizontal runs. Refer to Figure 4.

10
Power Wiring
The power supply lines must be run in weather-tight conduit to the
disconnect, and into the bottom of the unit control box. Provide
strain relief for all conduit with suitable connectors.
Provide flexible conduit supports whenever vibration transmission
may cause a noise problem within the building structure.
Insure all connections are made tight. (See Figure 6)
Note: For branch circuit wiring (main power supply to
unit disconnect), Wire size for the length of run should be
determined using the circuit ampacity found on the unit
nameplate and the N.E.C..
For more than 3 current carrying conductors in a raceway or cable,
for de-rating the ampacity of each conductor.
GROUNDING: THE UNIT MUST BE ELECTRICALLY
GROUNDED IN ACCORDANCE WITH LOCAL AND NATIONAL
CODES.
Control Wiring (Class II)
Note about 24 Volt Transformers:
Units have intergal circuit breakers in their low voltage transform-
ers. If the breaker trips, be sure to open the unit disconnect before
attempting to reset the breaker.
Some earlier model units have a replaceable fuse mounted in the
transformer. An extra fuse is taped down near the transformer. To
use this replacement fuse, remove the old one by pushing in and
turning counter-clockwise 1/4 turn, then pull it out. To insert the
new fuse, push in and turn clockwise until it stops.
CAUTION: Do not replace with a fuse of greater ampacity
than 3.5 amps.
Open and lock unit
disconnect. Failure to do so could result in severe
personal injury or death due to electrical shock.
Remove compressor access panel and control box panel to ac-
cess transformer. Reset by pressing in on the black reset button
located on the left side of the transformer.
Replace all panels before restoring power to the unit.
Important Note: The unit 24 volt transformer must not be
used to power Field Installed Accessories (FIA), except
for the ones that are factory supported.
Figure 5
Typical fan, motor, and sheave assembly
TO INCREASE M3/h CFM
Loosen the pulley adjustment set screw and turn sheave
clockwise
TO DECREASE M3/hCFM
Loosen the pulley adjustment set screw and turn sheave
counter-clockwise
TO INCREASE BELT TENSION
Loosen the nut (next to the idler sheave) that secures the
sheave in place. With a wrench, apply pressure clockwise
on the outside nut (round headed one), until tension de-
sired is reached. While holding pressure with the tension
nut, retighten the nut next to the idler sheave.
Electrical Connections
Electrical wiring and grounding must be installed in accor-
dance with local and national codes.
Electrical Power
It is important that proper electrical power is available for
the unit. Voltage variation should remain within the limits
stamped on the nameplate.
Power Entry
Holes are provided for low-voltage and high-voltage wiring.
It is not necessary to punch any new holes in either the in-
terior or exterior unit panels. If new holes are punched, per-
formance will be adversely affected unless they are re-
sealed to be both air- and watertight.
Disconnect Switch
Provide an approved weather-proof disconnect either on
the side of unit or within close proximity.
Over Current Protection
The branch circuit feeding the unit must be protected as
shown on the unit rating plate.

11
Zone Low
Sensor Voltage
Module Terminal Board
(ZSM) (LTB)
1 [ ] [ ] 1
2 [ ] [ ] 2
3 [ ] [ ] 3
4 [ ] [ ] 4
5 [ ] [ ] 5
Zone Temperature Sensor and low voltage terminal
designations are no longer R-W-Y-G-B etc, they are now 1-2-3
etc. Connections should be made using 1 to 1, 2 to 2, 3 to 3,
and so on. See example below.
Zone Temperature Sensor Terminal Strip
Terminal # Terminal I.D.
1ZTEMP
2 SIGNAL COMMON
3CSP
4MODE
5HSP
6 LED COMMON
7 HEAT LED
8 COOL LED
9SYSONLED
10 SERVICE LED
Emergency Shut Down
For Emergency Shut down, remove the jumper between LTB-
16 and LTB-17 and install normally closed contacts (Open at
Fault Condition). Immediate shut down will occur and the UCP
will be diabled.
Compressor Disable
To disable Compressor #1, remove the jumper between LTB-
13 and LTB-14 and install normally closed contacts (open to
disable).
To disable Compressor #2, (if applicable), remove the jumper
between LTB-14 and LTB-15 and install normally closed con-
tacts (open to disable).
Figure 6
Typical Field Wiring Diagram
Low voltage control wiring must not be run in conduit with
power wiring. Route low voltage (class II) colored wire from
zone sensor terminals through 7/8 inch bushing in the unit.
See dimensional data for control wire entry location. Make
connections as shown by the appropriate low voltage wiring
diagrams in Figure 7.
Zone Temperature Sensor conductors are standard thermostat
wire 22 to 14 ga. The only exceptions are Tracer/Tracker in-
stallations which utilize a serial communications link and re-
quire a shielded twisted pair of conductors between the
Tracer/Tracker and the (TCI) Communications Interface.
Recommended wire sizes and lengths for installing the Zone
Temperature Sensor are provided in Table 4. Ensure that the
wiring between the controls and the unit's termination point
does not exceed two and a half (5) ohms/conductor for the
length of the run. Resistance in excess of 5 ohms per conduc-
tor can cause deviation in the accuracy of the control.
Table 4 - DC Conductors
Diameter (mm2)Maximum Length (m)
0.33 45
0.50 76
0.75 115
1.30 185
2.00 300
NOTE: Do not run the electrical wires transporting DC
signals in or around conduit housing high voltage
wires.

12
Figure 7A
Zone Sensor Interconnecting Diagram

13
Figure 7B
Conventional Thermostat Interconnects

14
Wire Connection Guide
Holes are provided for low voltage and high voltage wiring. It is
not necessary to punch any new holes in either the interior or
exterior unit panels. If new holes are punched, performance
will be adversely affected unless they are resealed to be both
air tight and water tight. Refer to the Unit Dimensional Data
and unit view on page 5 for hole locations of units with or with
electric heat.
Correcting Improper Electrical
Phase Sequence
Proper compressor motor electrical phasing can be quickly de-
termined and corrected before starting the unit. Use a quality
instrument such as an Associated Research Model 45 Phase
Sequence Indicator and follow this procedure.
1. Open the electrical disconnect or circuit protection switch
that provides line power to the High Voltage Terminal Block
(HTB1) in the control panel.
2. Connect the phase sequence indicator leads to the HTB1
as follows:
Phase Seq. Lead HTB1 Terminal
Black (Phase A) L1
Red (Phase B) L2
Yellow (Phase C) L3
Bodily injury can result
from high voltage electrical components. If operating
checks must be performed with the unit operating, it
is the technician’s responsibility to recognize these
hazards and proceed safely. Failure to do so could
result in severe personal injury or death due to
electrical shock or contact with moving parts.
3 . Read the phase sequence on the indicator after turning
power on by closing the unit disconnect switch. The “ABC” in-
dicator on the face of the phase indicator will glow if phase is
ABC.
4. If the “CBA” indicator glows instead, open the unit main dis-
connect and interchange any two main line leads on HTB1. re-
close the unit main disconnect and recheck phasing.
5. Open units main disconnect before continuing with installa-
tion.
Open and lock unit
disconnect switch before continuing installation.
Failure to do so could result in severe personal injury
or death due to electrical shock or contact with
moving parts.
6. Disconnect the phase indicator.
Note: If a phase indicator is not available, follow the
electrical phasing sequence in the cooling start-up
section.
IMPORTANT: After completion of wiring, check all
electrical connections, including factory wiring within
the unit, and ensure all connections are tight. Replace
and secure all electrical box covers and access doors
before leaving unit or connecting power to circuit
supplying unit.
After all electrical wiring is complete, SET THE ZONE SEN-
SOR SWITCH TO THE OFF POSITIONAND THE FAN
SWITCH TO AUTO SO COMPRESSORAND FAN WILL NOT
RUN, and apply power by closing the system main disconnect
switch. This will activate the compressor crankcase heaters.
Do not change the zone sensor setting until power has been
applied long enough to evaporate any liquid R-22 in the com-
pressor. It is recommended the crankcase heaters be ener-
gized for 8 hours prior to starting.
Start-Up
Pre-Start Quick Check List
[ ] Is unit properly located and level with proper clearances?
See Figure 1A and 1B.
[ ] Is the duct work correctly sized, run, taped, insulated and
weather proofed with proper unit arrangement? (see duct
work installation)
[ ] Is condensate line properly sized, run, trapped and
pitched?
[ ] Is the filter of the correct size and number, clean and in
place?
[ ] Is the wiring properly sized and run in according to the unit
wiring diagram?
[ ] Are all wiring connections tight including those in unit and
compressor electrical boxes?
[ ] Has the unit been properly grounded and fused with the
recommended fuse size? (see wiring data)
[ ] Is the zone temperature sensor correctly wired and in a
good location?
[ ] Have the air conditioning systems been checked at the
service ports for charge and leak tested if necessary?
[ ] Does the condenser fan and indoor blower turn freely
without rubbing and are they tight on the shafts?
[ ] Has the indoor blower speed been determined and the
proper speed been set? (see air flow performance data)
[ ] Has all work been done in accordance with applicable local
and national codes?
[ ] Are all covers and access panels in place to prevent air
loss and safety hazards?

15
Starting The Unit In The Cooling Mode
IIMPORTANT NOTE: Before starting the system in the
cooling cycle, turn the zone sensor switch to “off”
and close the unit disconnect switch. This procedure
energizes the compressor crankcase heaters,
vaporizing any liquid refrigerant in the crankcase.
This is a precaution against foaming at start-up,
which could damage the compressor bearings. Allow
the heater to operate for a minimum of eight hours.
Verify that the unit airflow rate is adjusted according to infor-
mation provided in “Determining Evaporator Fan Adjustment”
section of this manual.
Note: See “Sequence of operation” in the unit
Service Facts for a complete description of cooling
operating sequence.
To start the unit in the cooling mode, close unit disconnect
switch and set the zone sensor system switch to COOL and
move the cooling setpoint approximately 10 degrees below
room temperature. There will be a delay of up to 5 minutes be-
fore the unit will start automatically.
To bypass time delays, and verify the operation of this unit
from the roof, use the “Test mode procedure” on page 3 and 4
of this manual.
Operating Pressures
After the unit has operated in the cooling mode for a short pe-
riod of time, install pressure gauges on the gauge ports of the
discharge and suction line valves.
Note: Always route refrigerant hoses through the port
hole provided and have compressor access panel in
place.
Check the suction and discharge pressures and compare
them to the normal operating pressures provided in the unit’s
Service Facts.
Note: Do not use pressures from Service Facts to
determine the unit refrigerant charge. The correct
charge is shown on the unit nameplate. To charge the
system accurately, weigh the charge.
Voltage
With the compressor operating, check the line voltage at the
unit. The voltage should be within the range shown on the unit
nameplate. If low voltage is encountered, check the size and
length of the supply line from the main disconnect to the unit.
The line may be undersized for the length of the run.
Cooling Shut Down
To exit the test mode, disconnect unit power for 3-5 seconds
and reapply. When running the unit using the zone sensor as
the control, position the selector switch at “Off”. There may
be a delay of up to 3 minutes before compressors shut down
and an additional 1 minute before the fan shuts down in this
setting.
Do not de-energize main power disconnect except when unit
is to be serviced. Power is required to keep air conditioning
compressor crankcase warm and boil off refrigerant in the oil.
Bodily injury can result
from high voltage electrical components. If operating
checks must be performed with the unit operating, it
is the technician’s responsibility to recognize these
hazards and proceed safely. Failure to do so could
result in severe personal injury or death due to
electrical shock or contact with moving parts.
Power-up Initialization
The “initialization” by the Unitary Control Processor (UCP) oc-
curs each time the system is powered-up. The UCP performs
internal self-diagnostics checks, which include identifying the
equipment components of its system, and the configuring of it-
self to that system. It also checks itself to be sure it is function-
ing correctly. On units with the optional economizer, the
damper is driven open for 15 to 20 seconds and then fully
closed for 90 seconds to calibrate itself. The UCP system indi-
cator LED is turned to “ON” within one second of start-up if
operation is correct.
The Unitary Control Processor (UCP) switches are factory set
to provide comfort for most applications. Control cycles may
be adjusted as indicated in the table below. These switches
function similar to the heat anticipator adjustment in conven-
tional thermostats.
Unitary Control Processor (UCP)
Switch Settings for Cycle Timing
Switch 1 Switch 2 Cycle Time
OFF OFF NORMAL (Factory Setting)
OFF ON LONGER
ON OFF SHORTER
ON ON *SPECIAL
* Special applications, where very short cycles are
necessary to prevent excessive temperature swings.
Starting the Unit in the Heating Mode
Check to ensure all grilles and registers are open and all unit
access doors are closed before start-up.
Place the zone system switch in the heat position.
Postition the heating setpoint approximately 10 degrees above
room temperature and place the fan switch in "Auto" or "On"
position.
Turn on main power supply.
Note: To bypass time delays, and verfiy the operation
of this unit from the roof, use the Test mode
procedure on page 3 and 4 of this manual.
Heating Shut-down
To exit the test mode, disconnect unit power for 3-5 seconds
and reapply. When running the unit using the zone sensor as
the control, position the selector switch at "Off". There will be a
delay of 60 seconds before the unit shuts down in this setting.

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(EDC) Evaporator Defrost Control
During low ambient operation (below 55 degree F for single
condenser fan units, and below 40 degree F for dual con-
denser fan units) compressor run time is accumulated by the
UCP. When compressor run time reaches approximately 10
minutes, an evaporator defrost cycle is initiated. The defrost
cycle lasts approximately 3 minutes.
During a defrost cycle, the compressor(s) are turned off and
the indoor motor continues to run. After completing the defrost
cycle the unit returns to normal operation, and the compressor
run time counter is reset to zero.
Economizer operation is not affected by a defrost cycle.
Defrost Module Test and operation
The defrost function is a time/temperature type operation very
similar to the time temperature defrost of the current Ft. Smith
products.
The only difference is that the timing function is provided by
the UCP, and the temperature information is provided by the
defrost module (located in the unit control box.)
Four (4) defrost time intervals can be selected by changing the
switch positions of switch 1, and switch 2 on the defrost
module. A defrost cycle is initated when the mechanical
heating is operating. The defrost termination switch is in the
closed position, and the accumulated compressor run time
exceeds the selected defrost time interval.
When defrost is initiated, the reversing valves are energized,
the compressors turned on, and the condenser fans are
turned off. The electric heaters are turned on to maintain zone
temperature. (If installed)
Once a defrost cycle has started, it will continue until it is
completed even if the zone sensor module has stopped calling
for heat.
The defrost cycle is terminated when one of three events
occur:
1. The defrost termination switch opens.
2. The defrost cycle has been operating for 10 minutes.
3. The high pressure control opens in either compressor
circuit.
Upon termination of a defrost cycle, the condenser fan(s) are
turned on for approximately 5 seconds before de-energizing
the reversing valves.
Defrost
Time Switch 1 Switch 2 Resistance between pins J2-3 & J2-4 on (DFM)
70 Min. OFF OFF Approximately 42.1 K
90 Min. ON OFF Approximately 30.3 K
60 Min. OFF ON Approximately 21.2 K
45 Min. ON ON Approximately 4.5 K
If the UCP reads an out of range temperature resistance from
the defrost module, due to an open or shorted circuit, a 10
minute defrost cycle will be initiated by the UCP after each 70
minutes of accumulated compressor run time. Any failure of
this type will indicate a heat and a cool failure at the low
voltage terminal block. The defrost module can be virtually
destroy, and as long as the on board relay remains intact to
energize the reversing valves defrost will still occur.
Final Installation Checklist
[ ] Does the unit run and operate as described in the “Se-
quence of Operation” in the unit Service Facts?
[ ] Is the condenser fan and indoor blower operating correctly,
with proper rotation and without undue noise?
[ ] Is the compressor operating correctly and has the system
been checked with a charging chart?
[ ] Have voltage and running currents been checked to deter-
mine if it is with limits?
[ ] Have the air discharge grilles been adjusted to balance the
system?
[ ] Has the ductwork been checked for air leaks and condensa-
tion?
[ ] Has the heating air temperature rise been checked?
[ ] Has the indoor airflow been checked and adjusted if neces-
sary?
[ ] Has the unit been checked for tubing and sheet metal
rattles and are there unusual noises to be checked?
[ ] Are all covers and panels in place and properly fastened?
[ ] Has the owner or maintenance personnel been given this
manual, warranty, and been instructed on proper operation
and maintenance?
Routine Maintenance by Owner
You can do some of the periodic maintenance functions for
your unit yourself; this includes replacing (disposable) or
cleaning (permanent) air filters, cleaning unit cabinet, cleaning
the condenser coil, and conducting a general unit inspection
on a regular basis.

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Season Maintenance - Cooling
To keep the unit operating safely and efficiently, the manufac-
turer recommends that a qualified serviceman check the entire
system at least once each year, or more frequently if condi-
tions warrant.
Examine these areas of unit:
1. Filters (for cleaning or replacement)
2. Motors and drive system components
3. Economizer gaskets (for possible replacement)
4. Condenser coils (for cleaning)
5. Safety Controls (for mechanical cleaning)
6. Electrical components and wiring (for possible replacement
or connection tightness)
7. Condensate drain (for cleaning)
8. Inspect the unit duct connections to ensure they are
physically sound and sealed to the unit casing.
9. Inspect the unit mounting support to see that it is sound.
10.Inspect the unit to ensure there is no obvious deterioration.
Season Maintenance - Heating
Complete the unit inspections and service routines described
below at the beginning of each heating season.
To prevent injury or death
due to electrical shock of contact with moving parts,
lock unit disconnect switch in open position before
servicing unit.
To prevent an explosion
and possible injury, death and equipment damage, do
not store combustible materials, gasoline or other
flammable vapors and liquids near the unit.
[ ] Visually inspect the unit to ensure that the airflow required
for the condenser coil is not obstructed from the unit.
[ ] Inspect the control panel wiring to verfiy that all electrical
connections are tight, and that wire insulation is intact.

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