CaptiveAire DOAS RTU Series User manual

Packaged Rooftop Unit - DOAS RTU Series
Installation, Operation, and Maintenance Manual
WARNING! FIRE OR EXPLOSION HAZARD
• Failure to follow safety warnings exactly could result in serious injury, death or property damage.
• Make sure to read and understand the installation, operation and service instructions in this manual.
• Improper installation, adjustment, alteration, service or maintenance can cause serious injury, death or
property damage.
• Read the installation, operating and maintenance instructions thoroughly before installing or servicing
this equipment. ALWAYS disconnect power and gas prior to working on unit.
FOR YOUR SAFETY
Do not store or use gasoline or other flammable vapors and liquids in the vicinity of this or any other
appliance. Installation and service must be performed by a qualified installer, service agency or gas supplier.
WHAT TO DO IF YOU SMELL GAS:
• Do not try to light any appliance. Do not touch any electrical switch; do not use any phone in your
building.
• Leave the building immediately. Immediately call your gas supplier from a phone remote from the
building.
• Follow the gas supplier’s instructions. If you cannot reach your gas supplier, call the fire department.
IMPORTANT
Some units may contain an energy recovery wheel. By virtue of their design, all energy recovery wheels
allow a level of return/exhaust air and contaminants to be recirculated into the supply airstream. Accepting
and operating this unit with or without the energy recovery wheel in operation increases the risk of airborne
bacteria, virus and contaminant spread between the return/exhaust air, into the fresh airstream.
In accordance with ANSI/ASHRAE/ASHE Standard 170-2017, energy recovery wheel technology should not
be used as a means of ventilation for certain Health Care Facilities. An ASHRAE Position Document on
Infectious Aerosols, approved by ASHRAE Board of Directors, dated April 14, 2020, also recommends that
energy recovery devices be bypassed for non-health care facility ventilation to help reduce the spread of
virus.
Any reduction of outdoor air % or volume below what this unit was designed for elevates the risk of airborne
bacteria, virus and contaminant recirculation back into the fresh airstream and the space.
Operating this unit with an exhaust level less than 50% of the supply level nullifies all return on investment
statements and limits the amount of energy recovery.
This unit, including the energy recovery wheel, must be serviced and maintained as per the Installation and
Operation Manual’s recommended frequencies.
RECEIVING AND INSPECTION
Upon receiving unit, check for any interior and exterior damage, and if found, report it immediately to the
carrier. Check that all accessory items are accounted for and free of damage. Turn the blower wheel by hand
to verify free rotation and check the damper (if supplied) for free operation.
A0033507
October 2020 Rev 00

2

3
Table of Contents
WARRANTY ............................................................................. 4
Coastal Applications ............................................................. 4
Furnace Warranty ................................................................. 4
CERTIFICATIONS ................................................................... 4
Listings and Standards ......................................................... 4
INSTALLATION ........................................................................ 5
Mechanical ............................................................................ 5
Inspection on Arrival ........................................................ 5
Unit Location - Site Preparation ....................................... 5
Rigging .................................................................................. 8
Curb and Ductwork ............................................................... 9
Duct Hanger Dimensions ............................................... 11
Duct Static Pressure Control .......................................... 13
Typical Submittal Drawing ............................................. 14
Furnace Condensation Drain .............................................. 15
Cooling Coil Trap ........................................................... 16
Gas ..................................................................................... 17
High Turndown Furnace ................................................ 17
High Altitude and Gas Type Orifice Sizing .......................... 19
LP Conversion Kit for RTU Series ...................................... 21
Pre-Conversion Unit Check-Out ......................................... 22
Gas Conversion Instruction ............................................ 23
Electrical ............................................................................. 24
Building to Unit Power Wiring Connection ..................... 25
Site Preparation – Controls ............................................ 25
HMI and Remote Room Sensor Installation ....................... 26
Typical Wiring Schematic ............................................... 27
Variable Frequency Drive (VFD) ......................................... 28
Variable Frequency Drive (VFD) Installation .................. 28
Input AC Power .............................................................. 28
VFD Output Power ......................................................... 29
VFD Programming ......................................................... 29
ACTECH SMV VFD ....................................................... 30
Make-up Air (MUA) Board Connectors .......................... 31
Optional Components ......................................................... 42
AC Interlock ................................................................... 42
Burner Interlock .............................................................. 42
Electric Cabinet Heater .................................................. 42
Component Location ........................................................... 42
Electric Heater Option .................................................... 49
Compressor Information ..................................................... 50
VZH 044/035/028 ........................................................... 50
Compressor VZH 065 .................................................... 50
Compressor VZH 088/117/170 ...................................... 51
Compressor Drive Information ............................................ 52
CDS803 Quick Menu Navigation ................................... 52
CDS803 Main Menu Navigation ..................................... 52
CDS302/303 Quick Menu navigation ............................. 53
CDS302/303 Main Menu ................................................ 53
OPERATION .......................................................................... 54
HMI Configuration Menu Access ........................................ 54
Remote (HMI) Control Panel .......................................... 54
HMI Notification Letters .................................................. 54
Configuring HMI .................................................................. 55
Communication .............................................................. 55
Advanced Options .......................................................... 55
Status ............................................................................. 55
About .............................................................................. 55
Scheduling ..................................................................... 56
Fan Speed and Damper Position Presets .......................... 56
Menu Descriptions .............................................................. 57
Menu Tree .......................................................................... 67
UNIT OPERATION ................................................................. 79
Start-Up Procedure ........................................................ 79
Start-Up Procedure Heating ............................................... 80
Furnace Start-Up Summary ........................................... 80
High Fire Burner Adjustment ......................................... 80
Low-Fire Burner Adjustment .......................................... 81
Final Start-Up Procedure ............................................... 81
Sequence of Operation ....................................................... 82
Operation Summary - Gas Heating ............................... 82
Flame Safety Control (FSC) ............................................... 83
Modulating Stage Sequence .............................................. 83
MUA Board and High Fire Start .......................................... 83
Re-Circulating Control Options ........................................... 84
Powered Exhaust ............................................................... 84
Outdoor Air Configuration ................................................... 84
Programmable Thermostat ................................................. 84
Heating, Cooling, Defrost, and Reheat ............................... 85
Economizer ......................................................................... 88
Psychrometric Chart ........................................................... 89
Fixed Dry Bulb Economizer .......................................... 89
Differential Dry Bulb Economizer .................................. 89
Fixed Enthalpy Economizer ........................................... 90
Differential Enthalpy Economizer ................................... 90
Energy Recovery (Optional) ............................................... 91
Purge and Pressurization ................................................... 91
Drive Motor .................................................................... 92
Frost Protection (Optional) ............................................. 92
Variable Speed Frost Prevention ................................... 92
Energy Recovery Exhaust Hoods ....................................... 92
Exhaust Fan ....................................................................... 92
Slide-Out Wheel ................................................................. 92
Network .............................................................................. 93
BACnet .......................................................................... 93
Device Instance, MAC Address, Baud Rate .................. 94
Changing the IP Address ............................................... 95
DDC Control Points (BACnet) ............................................ 96
LonWorks .................................................................... 100
DDC Faults .................................................................. 101
SERVICE INFORMATION ................................................... 103
Basic Service .................................................................... 103
Monitoring the A/C System .......................................... 103
Monitoring with Gauge Set .......................................... 104
Recovering Refrigerant from the System ..................... 104
Nitrogen Purging .......................................................... 105
Pressure Testing .......................................................... 105
Evacuating the System ................................................ 105
Charging an Empty System ......................................... 106
Charging System Low On Refrigerant ......................... 107
Removing Manifold Gauge Set .................................... 107
Troubleshooting ................................................................ 108
System Troubleshooting Chart .................................... 108
HMI Fault Codes .......................................................... 109
Compressor Drive VFD Troubleshooting Chart ................ 113
Compressor Troubleshooting Chart ................................. 115
Airflow Troubleshooting Chart .......................................... 116
Furnace Troubleshooting Chart ........................................ 117
Superheat and Subcooling ............................................... 118
Component Check/Testing ............................................... 119
MAINTENANCE ................................................................... 130
General Maintenance ....................................................... 130
Every 3 months ................................................................. 130
Heating Season ........................................................... 131
Cooling Season ........................................................... 131
Maintenance Quick Reference Chart ........................... 131
Coil Cleaning Procedure .............................................. 132
Filters ........................................................................... 133
Start-Up and Maintenance Documentation ...................... 135

4
WARRANTY
This unit comes with a standard 5-year parts warranty from date of shipment to be free from defects in
materials and workmanship, under normal use and service. An extended 10-year non-prorated parts
warranty is available at no extra charge when units are remotely monitored and maintained through a
Service Preventative Maintenance subscription (terms and conditions apply).
This warranty shall not apply if:
1. The equipment is not installed by a qualified installer per the MANUFACTURER’S installation
instructions shipped with the product.
2. The equipment is not installed in accordance with Federal, State, and/or Local codes and regulations.
3. The equipment is misused or neglected, or not maintained per the MANUFACTURER’S maintenance
instructions.
4. The equipment is not operated within its published capacity.
5. The invoice is not paid within the terms of the sales agreement.
The MANUFACTURER shall not be liable for incidental and consequential losses and damages potentially
attributable to malfunctioning equipment. Should any part of the equipment prove to be defective in
material or workmanship within the standard 5-year warranty period or the extended 10-year Preventative
Maintenance subscription, upon examination by the MANUFACTURER, such part will be repaired or
replaced by MANUFACTURER at no charge. The BUYER shall pay all labor costs incurred in connection
with such repair or replacement. Equipment shall not be returned without MANUFACTURER’S prior
authorization, and all returned equipment shall be shipped by the BUYER, freight prepaid to a destination
determined by the MANUFACTURER.
NOTE: To receive warranty coverage, register this product by filling out the Start-up and
Maintenance Document. Fax the form to 1-919-554-9374 or call 1-866-784-6900 for email
information.
Coastal Applications
Units installed within 1-mile of salt-water coasts and waterways must be equipped with an E-Coated
Outdoor Coil. Position the unit, so the fresh air inlet or outdoor coil is protected from direct salt spray.
Failure to protect the fresh air inlet or outdoor coil from direct salt spray will void the unit’s warranty.
Furnace Warranty
Subject to all terms stated herein, the MANUFACTURER warrants to BUYER the stainless steel heat
exchanger to be free from defects in material and workmanship under normal use and service for
25-years from the date of manufacture and warranty is limited to replacement of the heat exchanger only.
CERTIFICATIONS
Listings and Standards
This unit is ETL-listed to the following standards:
• Standard for Safety Heating and Cooling Equipment ANSI/UL 1995, CSA 22.2 no. 236
• American National Standard/CSA Standard for Gas Unit Heaters and Gas-Fired Duct Furnaces ANSI
Z83.8-2016, CSA 2.6-2016
This unit has been tested in accordance to the following standards:
• ANSI/AHRI Standard 340/360 – 2007
• ANSI/ASHRAE Standard 37 – 2009

5
INSTALLATION
It is imperative that this unit is installed and operated with the designed airflow, gas, and electrical supply in
accordance with this manual. If there are any questions about any items, please call the service
department at 1-866-784-6900 for warranty and technical support issues.
Mechanical
Inspection on Arrival
1. Inspect unit on delivery.
2. Photograph any visible damage.
3. Report any damage to the delivery carrier.
4. Request a written inspection report from the Claims Inspector to substantiate a claim.
5. File a claim with the delivery carrier.
6. Check unit’s rating plate to verify proper electric and fuel type to meet job requirements.
7. Compare unit received with description of product ordered.
Unit Location - Site Preparation
• Do not locate any gas-fired equipment near corrosive, explosive vapors such as chlorinated or acid
vapors.
• Avoid overhead power lines, or other utility access points to prevent accidental contact or damage.
• Provide clearance around the installation site to safely rig and lift the equipment into its final position
onto adequate supports. Refer to the manufacturer’s estimated weights.
• Consider general service and installation space when locating the unit.
• Locate the unit close to the space it will serve to reduce long and twisted duct runs.
• Do not allow the air intake to face prevailing winds. The airflow switch may trip in high winds.
• Situate the unit above ground or at roof level high enough to prevent precipitation from being drawn
into its inlet.
• The inlet must also be located at least 10 feet away from any exhaust vents.
• The inlet must be in accordance with the applicable building code provisions for ventilation air.
• The unit must have adequate structural support, or the equipment or building could be damaged.
• Do not alter or otherwise restrict combustion or ventilation openings.
IMPORTANT
For gas units, to prevent premature heat exchanger failure, do not locate any gas fired unit in
areas where chlorinated, halogenated, or acid vapors are present in the atmosphere.

6
Figure 1 - Unit Clearance
CLEARANCE TO COMBUSTIBLE MATERIALS
This equipment may be installed with clearances from the equipment to combustible material not
less than 0 inches from the top, bottom, condenser side, front and back. The flue side must be
installed 3 feet from combustible materials. Refer to Figure 1 for clearance details.
SERVICE CLEARANCE
For service accessibility and performance, this unit must have at least 3 feet of clearance on the
intake and supply sides. Size 1, 2, and 3 units should have 3 feet of clearance on the condensing
coil side, and size 4 units should have 4 feet. Clearance above condenser fans should be at least
10 feet. Refer to Figure 1 for clearance details.
Size 1, 2, and 3 Unit Clearance
CLEARANCE TO
COMBUSTIBLES 0 FT.
Size 4 Unit Clearance
CLEARANCE TO
COMBUSTIBLES 0 FT.
SERVICE
CLEARANCE 4 FT.
CLEARANCE TO
COMBUSTIBLES 0 FT.
SERVICE
CLEARANCE 3 FT. SERVICE CLEARANCE
AND CLEARANCE TO
COMBUSTIBLES 3 FT.
CLEARANCE TO
COMBUSTIBLES 0 FT.
CLEARANCE TO
COMBUSTIBLES 0 FT.
SERVICE
CLEARANCE 3 FT.
CLEARANCE TO
COMBUSTIBLES 0 FT.
SERVICE
CLEARANCE 3 FT.
SERVICE CLEARANCE AND
CLEARANCE TO
COMBUSTIBLES 3 FT.

7
Figure 2 - ERV Unit Clearances
CLEARANCE TO COMBUSTIBLE MATERIALS
This equipment may be installed with clearances from the equipment to combustible material not
less than 0 inches from the top, bottom, condenser side, front and back. The flue side must be
installed 3 feet from combustible materials. Refer to Figure 2 for clearance details.
SERVICE CLEARANCE
For service accessibility and performance, this unit must have at least 3 feet of clearance on the
intake and supply sides. Size 2 and 3 ERV units should have 3 feet of clearance on the condensing
coil side, and size 4 ERV units should have 4 feet. Clearance above condenser fans should be at
least 10 feet. Refer to Figure 2 for clearance details.
Size 2 and 3 Unit Clearance
Size 4 Unit Clearance
SERVICE
CLEARANCE 4 FT.
CLEARANCE TO
COMBUSTIBLES 0 FT.
SERVICE CLEARANCE
AND CLEARANCE TO
COMBUSTIBLES 4 FT.
CLEARANCE TO
COMBUSTIBLES 0 FT.
SERVICE
CLEARANCE
3 FT.
CLEARANCE TO
COMBUSTIBLES
0 FT.
SERVICE
CLEARANCE
4 FT.
SERVICE
COMBUSTIBLES 0 FT.
CLEARANCE TO
COMBUSTIBLES
0 FT.
SERVICE
CLEARANCE
3 FT.
CLEARANCE TO
COMBUSTIBLES 0 FT.
SERVICE CLEARANCE
AND CLEARANCE TO
COMBUSTIBLES 4 FT.
SERVICE
CLEARANCE 3 FT.
CLEARANCE TO
CLEARANCE
4 FT.

8
Rigging
Spreader bars must be used and should extend past the edges of the equipment to avoid damage to the
casing. Not using spreader bars may cause damage to the unit casing. Refer to Figure 3 for rigging
details.
WARNING: DO NOT LIFT UNIT BY THE INTAKE LOUVER, OR DOOR OPENINGS – USE ALL LIFTING
POINTS PROVIDED WITH A SPREADER BAR OR SLINGS UNDER THE UNIT – USE CARE NOT TO
DAMAGE COILS, SWITCHES OR PROTRUDING SHEET METAL COMPONENTS.
• Units are supplied with four lifting eyes on the bottom corners of the structural rails.
• Always use spreader bars to prevent damage to the unit casing.
• Test lift the unit approximately 2 feet to verify proper center of gravity lift point. To avoid dropping unit,
re-position lifting point if unit is not level. Failure to properly lift unit could result in unit dropping and
possibly crushing operator/technician, which could result in death or serious injury and possible
equipment or property-only damage.
Figure 3 - Rigging (Size 2 Unit Shown)
WARNING!!
Ensure that all the lifting equipment used is properly rated for the weight of the unit being lifted.
Each of the cables (chains or slings), hooks, and shackles used to lift the unit must be capable of
supporting the entire weight of the unit. Lifting cables (chains or slings) may not be of the same
length. Adjust as necessary for even unit lift. Other lifting arrangements could cause equipment
or property damage. Failure to follow instructions above or properly lift unit could result in unit
dropping and possibly crushing operator/ technician which could result in death or serious
injury.
Spreader
Bar
Lifting Eyes
Located in 4 Corners
Lifting Eyes
Located in 4 Corners
Lifting Eyes
Located in 4 Corners
Lifting Eyes
Located in 4 Corners
Lifting Eyes
Located in 4 Corners
Forklift
Pockets

9
Curb and Ductwork
This unit was specified for a specific CFM and static pressure. The ductwork attached to this unit will
significantly affect airflow performance. When using rectangular ductwork, elbows must be radius throat,
radius back with turning vanes. Flexible ductwork and square throat/square back elbows should not be
used. Any transitions and/or turns in the ductwork near the fan outlet will cause system effect. System
effect will drastically increase the static pressure and reduce airflow. Table 1 and Table 2 detail the
minimum fan outlet duct sizes required for optimal fan performance.
•Follow SMACNA guides and manufacturer’s requirements for the remaining duct run. Units
designed for rooftop installation should be installed on a prefabricated or factory-built roof curb. Follow
curb manufacturer’s instructions for proper curb installation.
•Do not use unit to support ductwork in any way. This may cause damage to the unit.
• If installed in a geographical area where snow accumulates, the unit should be installed on a curb and/
or rail elevated not less than 12-inches above any surface. Verify installation meets local code height
requirements.
• Verify duct connection and unit supply outlet are properly aligned and sealed. Use gasket between the
curb and unit (Figure 4).
• The curb and unit must be level, or the unit may leak or be damaged. If necessary, use shims to level
the unit. Shims may be required depending upon curb installation and roofing material.
• Secure unit to curb with all available mounting points through vertical portion of the base assembly
rails (Figure 4). Use lug screws, anchor bolts, or other suitable fasteners (not furnished).
• Check all fasteners are secure and tight.
WARNING!!
Failure to properly size ductwork may cause system effects and reduce the performance of the
equipment.
Table 1 - Recommended Supply Ductwork Sizes Down Discharge
Unit Size Down Discharge
Duct Size (Inches)
Down Return Duct
Size (Inches)
Side Return
Duct Size (Inches)
Straight Duct
Length
1 21-1/4” x 19-1/4” 28” x 10” 29” x 10-1/2” 54”
2 20-1/4” x 30-1/4” 36” x 9” 36-1/4” x 11-1/4” 54”
3 39” x 21-1/2” 45-1/2” x 13-1/2” 45-1/2” x 10-3/4” 78”
4 39-3/4” x 31” 74 x 12-1/4” 76-1/2” x 16-1/4” 96”
Table 2 - Recommended Supply Ductwork Sizes Side Discharge
Unit Size Side Discharge
Duct Size (Inches)
Down Return Duct
Size (Inches)
Side Return
Duct Size (Inches)
Straight Duct
Length
1 20” x 19-1/4” 28” x 10” 29” x 10-1/2” 48”
2 20” x 14” 36” x 9” 36-1/4” x 11-1/4” 48”
3 25” x 14” 45-1/2” x 13-1/2” 45-1/2” x 10-3/4” 54”
4 34” x 21-1/4” 74” x 12-1/4” 76-1/2” x 16-1/4” 78”

10
Figure 4 - Curb
Side Return Duct/Access Panel Install, refer to Figure 5 Detail A.
• Install gasket material around the upper and side edges.
• Install ductwork using self-tapping screws.
• Use caulk/sealant around the upper and side edges.
• Do not use caulk/sealant on the lower edge. Use only self-tapping screws to mount ductwork.
Side Discharge Duct Install, refer to Figure 5 Detail B.
• Mount ductwork to the lip of the side discharge opening.
• Use self-tapping screws to secure ductwork.
• Verify the ductwork is clear for opening the top access panel door.
Figure 5 - Side Discharge, Side Return
Curb Attachment
Point
Gasket
Curb
1. Discharge Outlet
2. Upper Edge - Use gasket/sealant for side
return duct or access panel.
3. Side Edges - Use gasket/sealant for side
return duct or access panel.
4. Lower Edge - DO NOT USE gasket/sealant.
4
1
22
3
3
Detail BDetail A

11
Duct Hanger Dimensions
Figure 6 provides details for standard curbs, and Figure 7 provides details for ERV curbs. Refer to Table
3 and Table 4 on page 12 for Bill of Materials and curb dimensions.
Use 1/4”-20 x 5/8” Phillips pan head screws and nuts when assembling duct hangers, refer to Figure 8 on
page 12.
Figure 6 - Standard Curb
Figure 7 - ERV Curb
E
D
B
C
F
1
1
2
3
2
3
A
G
INTAKE
END
RETURN DISCHARGE
ENERGY RECOVERY
VENTILATOR END
RETURN DISCHARGE
F
D
C
B
A
G
E
H
1
1
2
32
3

12
Figure 8 - Duct Hanger Assembled
Table 3 - Duct Hanger Bill of Materials
Ref Size 1 Size 2 Size 3 Size 4
1RTU1DHR = Quantity x 1 RTU2DHR = Quantity x 2 RTU3DHR = Quantity x 1 N/A
2RTU1DHL = Quantity x 3 RTU2DHL = Quantity x 3
NOTE: ERV Quantity x 4
RTU3DHL = Quantity x 3
NOTE: ERV Quantity x 4
RTU4DHL = Quantity x 3
NOTE: ERV Quantity x 4
3RTU1DHD = Quantity x 2 RTU2DHD = Quantity x 2 RTU3DHD = Quantity x 2 RTU4DHD = Quantity x 2
Table 4 - Duct Hanger Curb Dimensions
Reference Size 1 Size 2 Size 2 ERV Size 3 Size 3 ERV Size 4 Size 4 ERV
A 12-3/4” 12-1/4” 18” 16-5/8” 17-7/8” 15-1/2” 15-5/8”
B 36-1/4” 33-3/8” 40-1/4” 48-1/8” 41-3/8” 60-1/4” 49-3/8”
C 59-1/4” 55-1/2” 60-1/4” 71-5/8” 72” 93-3/4” 93-7/8”
D N/A 1-3/4” 73-7/8” N/A 90” N/A 110”
E 31-1/4” 39-1/2” 1-3/4” 48-3/8” N/A N/A N/A
F 5-1/4” 3-3/8” 39-1/2” 2-3/4” 40-3/8” 29-3/8” N/A
G 27-3/4” 35-3/8” 7-3/8” 43-1/2” 2-5/8” 70-3/4” 29-3/8”
H N/A N/A 29-1/8” N/A 43-1/2” N/A 70-7/8”
Non ERV Curb ERV Curb

13
Duct Static Pressure Control
Units equipped with an Electrically Controlled Motors (ECMs) or Variable Frequency Drives (VFDs) driven
supply fan, the duct static pressure control option can be used to monitor duct pressure.
1. Locate where the pressure transducer is installed in the control cabinet.
2. Install the static pitot tube in a straight section of ductwork where the airflow is laminar and consistent.
3. Connect the high side tubing to the static pitot tube.
4. Route the tubing through the bottom of the unit to the high side port on the pressure transducer.
5. The low side pressure tubing will be connected to a brass port, located by the control cabinet doors.
This will be connected from the factory.
Figure 9 - Duct Static Pressure Control Details
Airflow from
Supply Fan
Pressure Transducer
Located in Control Cabinet
Ductwork
Low Side
Pressure Tubing
To Brass Port Located by Control
Cabinet Doors.
Static Pitot Tube
High Side
Pressure Tubing

14
Typical Submittal Drawing

15
Furnace Condensation Drain
In some applications, condensation can form in the flue collection box, especially when furnaces are
located downstream of cooling coils or operate in a high-efficiency range. If condensation occurs in the flue
collection box, there are fittings in the bottom of the flue collection box to drain condensation out of the box.
The burner in the unit is provided with a condensation drain assembly located underneath this fitting for the
condensation to collect. The drain will need to be connected to field piping to handle the condensation
properly.
Consult your local code as to the proper drainage regulations of the condensation. A heated drain option is
available to prevent the internal drain piping from freezing. If drains are field piped, ensure that the field
piping is piped in a fashion to prevent the condensation from freezing. Do not plug the holes under any
circumstance as it will cause the burners to overflow.
The standard efficiency furnace drain (Figure 10, detail A) is piped to the exterior of the unit via 5/16”
silicone tubing. A 1/4” female NPT fitting is provided external to the unit to allow for field piping if required.
If piping is added to the unit, freeze protection should be added to prevent damage to the field-installed
piping.
The high-efficiency furnace drain (Figure 10, detail B) is fitted with a condensation float switch assembly,
located in the bottom main cabinet, from the factory. A condensation drain must be field piped through the
base of the unit using 3/4” PVC schedule 80 smooth fittings per the above requirements. A 2” deep trap
must be field installed downstream of the unit to ensure adequate flow.
NOTE: Seal ALL base penetrations with appropriate filler (caulk or all-purpose putty) to prevent
water from entering the space.
Figure 10 - Condensation Drain(s)
To test the factory-installed condensation float switch assembly:
• Turn the unit on, start the heating system. If the heating system does not run, verify the condensation
float switch assembly wiring is correct.
• Remove the condensation float switch from the assembly. Lift the switching arm with a screwdriver.
The heating system should shut off immediately. If not, check that the condensation float switch
assembly’s wiring connections are secure and tight. Re-check the float switch for proper operation.
1. Standard efficiency drain connection. 1/4” NPT trap recommended.
2. 1/2”, 3/4”, or 1” NPT gas connection depending on furnace size.
3. Factory-installed high-efficiency condensation float switch assembly and wiring.
4. High-efficiency drain connection. 3/4” PVC schedule 80.
5. After drain pipe installation, seal base penetrations with an appropriate filler.
Standard Efficiency Drain - Detail A High-Efficiency Drain - Detail B
1
2
34
5

16
Cooling Coil Trap
There is a field plumbing connection that is required for the DX/cooling coil. This connection is for the drain
pan located under the DX/cooling coil. Also, it is recommended that all plumbing connections be sealed
with Teflon tape or pipe dope.
Install Condensate Trap Assembly to 1” threaded drain pan connection. Use low-profile couplings and 1”
PVC piping to connect on-site drainage to the Condensate Trap Assembly. DO NOT USE UNIONS. The
Condensate Trap Assembly is important for two reasons. First, it will allow drainage to be piped to the most
convenient area. Second, it will keep air from being drawn into the system, impeding drainage. The top lids
of the Condensate Trap Assembly should be removable to allow for cleaning of the trap.
Figure 11 - Condensate Trap Assembly Details
Minimum 1"
4” Trap Height

17
Gas
Installation of gas piping must conform with local building codes, or in the absence of local codes to the
National Fuel Gas Code, ANSI Z223.1 (NFPA 54) – latest edition. In Canada, installation must be in
accordance with CAN/CGA-B149.1 for natural gas units and CAN/CGA-B149.2 for propane units.
WARNING: Inlet gas pressure must not exceed pressure indicated on nameplate. See unit
nameplate for proper gas supply pressure and gas type.
1. Always disconnect power before working on or near a heater. Lock and tag the disconnect
switch and/or breaker to prevent accidental power-up.
2. Piping to the unit should conform to local and national requirements for type and volume of gas
handled, and pressure drop allowed in the line. Refer to the Gas Engineer’s Handbook for gas line
capacities.
3. The incoming pipe near the heater should be sized to match the connection on the outside of the unit.
Connection size is 1/2”, 3/4”, or 1” NPT depending on furnace size. See “Condensation Drain(s)”
Detail A on page 13. Verify unit inlet size to job-specific sheet. Avoid multiple taps in the gas supply,
so the unit always has a steady supply of gas.
4. Install a ground joint union with brass seat and a manual shut-off valve external to the unit casing.
Install shut-off valve adjacent to the unit for emergency shut-off and easy servicing of controls. See
Figure 12 on page 18.
5. Provide a sediment trap, as shown in Figure 12, before each unit and where low spots in the pipeline
cannot be avoided.
6. A minimum 1/8” NPT plugged tapping, accessible for test gauge connection, must be installed
immediately upstream of the gas supply connection to the appliance.
7. Clean out the gas line to remove debris before making connections. Purge line to remove air before
attempting to start unit. Purging air from gas lines should be performed as described in ANSI Z223.1-
latest edition “National Fuel Gas Code,” or in Canada as described in CAN/CGA-B149.
8. All field gas piping must be pressure/leak tested before unit operation. Use a non-corrosive bubble
forming solution or equivalent for leak testing. The heater and its individual shut-off valve must be
disconnected from the gas supply piping system during any pressure testing of that system at test
pressures over 1/2 psi. The heater must be isolated from the gas supply piping system by closing its
individual manual shutoff valve during any pressure testing of the gas supply piping system at test
pressures equal to or less than 1/2 psi.
9. This unit requires a constant 7” water column (wc) minimum for natural gas supply (LP 11 in. wc
minimum) when the unit is operating at maximum gas flow. If the gas supply exceeds 14” wc, it will
damage the internal valve components. If the gas supply drops below 7” wc (LP 11 in. wc), the heater
may not perform to specifications. Refer to Table 5 for gas pressure type and pressure rating.
High Turndown Furnace
The high turndown furnace will be divided into two separate furnace assemblies within the same cabinet.
This results in a two stage heat source that can stage up and down to meet demand. Since the furnace is
split unevenly, staging on the smallest will result in significantly higher turndown and greater control over
building conditions. An additional Flame Safety Controller (FSC), safety valve, modulating valve, and high
pressure switch (if equipped) will be installed. See Figure 21 on page 46.
NOTICE
Refer to the heater rating plate for determining the minimum gas supply pressure for obtaining the
maximum gas capacity for which this heater is specified.

18
Table 5 - Gas Pressure
Figure 12 - Gas Connection Diagram
Gas Pressure Type Gas Pressure
Inlet Pressure - Natural Gas 7 - 14 Inches WC
Inlet Pressure - Propane (LP) 11 - 14 Inches WC
Maximum Manifold Pressure - Natural Gas 3.5 Inches WC Maximum
Maximum Manifold Pressure - Propane (LP) 10 Inches WC Maximum
Minimum Manifold Pressure - Natural Gas 0.15 Inches WC Maximum
Minimum Manifold Pressure - Propane (LP) 0.75 Inches WC Maximum
1. Gas Supply Line Connection
2. Manual Gas Shut-off Valve
3. Plugged 1/8” NPT Test Gauge Connection
4. Ground Joint Union with Brass Seat
5. Sediment Trap
A. Minimum Depth = 6”
B. Minimum = 6”
4
2
5
A
B
1
3Unit
To Main
Control Valve

19
High Altitude and Gas Type Orifice Sizing
The burner orifices should be sized per Table 6 and Table 7, depending on fuel type, furnace size, and
altitude. Standard orifice sizes are for sea level. The unit should be ordered with the altitude specific
orifices, or the parts should be ordered through the manufacturer (Table 8 on page 20). Refer to main gas
valve documentation for instructions to convert gas valve spring from Natural to LP and vice versa.
NOTE: 50,000 – 100,000 BTU High-Efficiency Natural Gas furnaces use 2.3mm Drill Size at 0 – 3999
ft. Follow charts for all other altitudes.
Table 6 - Natural Gas High Altitude Charts
Natural Gas High Altitude Conversion
Size 3 Size 2 and 3 Size 1, 2, and 3
High Altitude for 500,000
BTU
High Altitude for 400,000
BTU
High Altitude for 300,000 to 50,000
BTU
Altitude
(Feet) Input Rate Drill Size Input Rate Drill Size Input Rate Input Rate Input Rate Drill Size
0 - 1,999 500,000 #33 400,000 #41 300,000 200,000 150,000 #3/32
2,000 - 2,999 479,998 #35 384,000 #42 288,000 192,000 144,000 2.35mm
3,000 - 3,999 460,797 #35 368,640 2.35mm 276,480 184,320 138,240 2.3mm
4,000 - 4,999 442,668 #36 353,894 2.3mm 265,421 176,947 132,710 #43
5,000 - 5,999 424,668 #36 339,739 #43 254,804 169,869 127,402 2.25mm
6,000 - 6,999 407,680 #37 326,149 2.25mm 244,612 163,075 122,306 #44
7,000 - 7,999 391,372 #38 313,103 #44 234,827 156,552 117,414 2.15mm
8,000 - 8,999 375,716 #38 300,579 #45 225,434 150,290 112,717 #46
9,000 - 10,000 360,686 #40 288,556 #46 216,417 144,278 108,209 #47
Natural Gas High Altitude Conversion
Size 4 Size 4
High Altitude for 600,000 BTU High Altitude for 500,000 to 200,000 BTU
Altitude
(Feet) Input Rate Drill Size Input Rate Input Rate Input Rate Input Rate Drill Size
0 - 1,999 600,000 3.4mm 500,000 400,000 300,000 200,000 3.3mm
2,000 - 2,999 576,000 #30 479,998 384,000 288,000 192,000 #30
3,000 - 3,999 552,960 #30 460,797 368,640 276,480 184,320 #31
4,000 - 4,999 530,482 #30 442,668 353,894 265,421 176,947 #31
5,000 - 5,999 509,608 #30 424,668 339,739 254,804 169,869 #31
6,000 - 6,999 489,224 #30 407,680 326,149 244,612 163,075 #31
7,000 - 7,999 469,654 #31 391,372 313,103 234,827 156,552 #32
8,000 - 8,999 450,868 #31 375,716 300,579 225,434 150,290 #32
9,000 - 10,000 432,834 #32 360,686 288,556 216,417 144,278 #33

20
Table 7 - LP Gas High Altitude Charts
LP Gas High Altitude Conversion
Size 3 Size 2 and 3 Size 1, 2, and 3
High Altitude for 500,000
BTU
High Altitude for 400,000
BTU High Altitude for 300,000 to 50,000 BTU
Altitude
(Feet) Input Rate Drill Size Input Rate Drill Size Input Rate Input Rate Input Rate Drill Size
0 - 1,999 500,000 1/16” 400,000 1.45mm 300,000 200,000 150,000 #54
2,000 - 2,999 479,998 #53 384,000 #54 288,000 192,000 144,000 #54
3,000 - 3,999 460,797 #54 368,640 #54 276,480 184,320 138,240 #55
4,000 - 4,999 442,668 #54 353,894 #54 265,421 176,947 132,710 #55
5,000 - 5,999 424,668 #54 339,739 #54 254,804 169,869 127,402 #55
6,000 - 6,999 407,680 #54 326,149 #55 244,612 163,075 122,306 #55
7,000 - 7,999 391,372 #54 313,103 #55 234,827 156,552 117,414 #56
8,000 - 8,999 375,716 #55 300,579 #55 225,434 150,290 112,717 #56
9,000 - 10,000 360,686 #55 288,556 #56 216,417 144,278 108,209 #57
LP Gas High Altitude Conversion
Size 4 Size 4
High Altitude for 600,000 BTU High Altitude for 500,000 to 200,000 BTU
Altitude
(Feet) Input Rate Drill Size Input Rate Input Rate Input Rate Input Rate Drill Size
0 - 1,999 600,000 #45 500,000 400,000 300,000 200,000 #45
2,000 - 2,999 576,000 #46 479,998 384,000 288,000 192,000 #46
3,000 - 3,999 552,960 #47 460,797 368,640 276,480 184,320 #47
4,000 - 4,999 530,482 #47 442,668 353,894 265,421 176,947 #47
5,000 - 5,999 509,608 #47 424,668 339,739 254,804 169,869 #47
6,000 - 6,999 489,224 #48 407,680 326,149 244,612 163,075 #48
7,000 - 7,999 469,654 #48 391,372 313,103 234,827 156,552 #48
8,000 - 8,999 450,868 #49 375,716 300,579 225,434 150,290 #49
9,000 - 10,000 432,834 #49 360,686 288,556 216,417 144,278 #49
Table 8 - Orifice Part Numbers and Quantity Charts
Orifice Part Numbers Orifice Quantity per Furnace
Size Part # AX # Size Part # AX # Size 1, 2, and 3 Qty Size 4 Qty
#30 BG100-30 A0029277 #49 BG100-49 A0029283 50,000 BTU 2 N/A -
#31 BG100-31 A0029278 #50 BG100-50 A0029284 75,000 BTU 3 N/A -
#32 BG100-32 A0029279 #53 BG100-53 A0030724 100,000 BTU 4 N/A -
#33 BG100-33 A0029280 #54 BG100-54 A0023048 125,000 BTU 5 N/A -
#35 BG100-35 A0029281 #55 BG100-55 A0023049 150,000 BTU 6 N/A -
#36 BG100-36 A0030719 #56 BG100-56 A0023057 200,000 BTU 8 200,000 BTU 4
#37 BG100-37 A0030721 #57 BG100-57 A0028803 300,000 BTU 12 300,000 BTU 6
#38 BG100-38 A0030722 1/16” BG100-116 A0030725 400,000 BTU 15 400,000 BTU 8
#40 BG100-40 A0030723 1.45mm BG101-16 A0023052 500,000 BTU 15 500,000 BTU 10
#41 BG100-41 A0023045 2.15mm BG101-21 A0023055 N/A - 600,000 BTU 11
#42 BG100-42 A0023050 2.25mm BG101-20 A0023054
#43 BG100-43 A0023047 2.3mm BG101-05 A0023051
#44 BG100-44 A0023046 2.35mm BG101-19 A0023053
#45 BG100-45 A0028800 3.3mm BG101-08 A0029285
#46 BG100-46 A0028801 3.4mm BG101-09 A0030726
#47 BG100-47 A0028802 #3/32 BG101-3/32 A0023044
#48 BG100-48 A0029282