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Form O-CAUA, P/N 164772 R7, Page 1

Operation, Maintenance, and Service

Form O-CAUA (Version A)

Obsoletes Form O-CAUA

KEEP THIS BOOKLET FOR MAINTENANCE

AND SERVICE REFERENCE.

Model CAUA

with Optional Cased Cooling Coil

and Optional Mixing Box

CQS

Applies to: Model CAUA

Gas-Fired Indoor

Vertical (Upow),

Power-Vented Heater

WARNING:

FIRE OR EXPLOSION HAZARD

Failure to follow safety warnings exactly could result in serious injury, death, or

property damage.

Be 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.

— Do not store or use gasoline or other ammable vapors and liquids in the vicinity

of this or any other appliance.

— 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 re department.

— Installation and service must be performed by a qualied installer, service agency,

or the gas supplier.

Summary of content (16 pages)

PAGE 1
Form O-CAUA (Version A) Obsoletes Form O-CAUA Operation, Maintenance, and Service Model CAUA Gas-Fired Indoor Vertical (Upflow), Power-Vented Heater Applies to: T N P M TY UA E RO LITY SYST RA DU CT WA R Q C U S TO M E R CQS STA RT-UP AG C S PROC CY E EN VERGE S N ON Model CAUA with Optional Cased Cooling Coil and Optional Mixing Box ! WARNING: FIRE OR EXPLOSION HAZARD Failure to follow safety warnings exactly could result in serious injury, death, or property damage.
PAGE 2
TABLE OF CONTENTS 1.0 General................................................................. 2 2.0 MAINTENANCE................................................. 2-6 2.1 Maintenance Schedule..........................................2 2.2 Maintenance Procedures......................................3 2.2.1 Blower and Blower Motor ............................... 3 2.2.2 Filters................................................................ 3 2.2.3 Gas Valve....................................................
PAGE 3
2.2 Maintenance Procedures 2.2.1 Blower and Blower Motor FIGURE 1 - Check Belt Tension 2.2.2 Filters (Applies to a heater with either an optional return air filter cabinet; an outside air/return air mixing box with filters; or an inlet base with filters.
PAGE 4
2.0 Maintenance (cont'd) 2.2 Maintenance Procedures (cont'd) 2.2.3 Gas Valve WARNING The operating valve is the prime safety shutoff. All gas supply lines must be free of dirt or scale before connecting to the unit to ensure positive closure. See Hazard Levels, page 2. S Instructions: Remove external dirt accumulation and check wiring connections. The combination gas valve must be checked annually to ensure that the valve is shutting off gas flow completely.
PAGE 5
CAUTION: Use of eye protection is recommended. 1. Shut the gas supply off upstream of the combination valve. 2. Turn off the electric supply. 3. Remove the burner compartment door. 4. Disconnect the union and remove the gas pipe from the inlet of the gas valve. 5. Mark and disconnect the electrical wires to the gas valve. Disconnect the flame sensor wire, the flame rollout switch wires, and the ignitor wire at the burner box cover. Mark and disconnect the ignitor ground wire at the terminal board.
PAGE 6
2.0 Maintenance (cont'd) 2.2 Maintenance Procedures (cont'd) 2.2.5 Ignition System (cont'd) 2.2.6 Cleaning the Heat Exchanger CAUTION: Eye protection is recommended. 2.2.7 Venter Motor and Wheel 2.2.8 Vent or Vent/ Combustion Air System 2.2.9 Condensate Drain CAUTION: Due to high voltage on the spark wire and electrode, do not touch when energized. See Hazard Levels, Page 2. Flame Sensor - On the left side of the burner rack, locate the flame sensor.
PAGE 7
3.1 Control Locations FIGURE 4 - Control Locations in the Electrical Compartment (Remove the control compartment access panel) To service this heater, it is necessary to understand the normal operating functions of the heater controls. Refer to FIGURE 4 to identify and locate the controls. Thermostat Terminal Strip Contactor or Starter Transformer Relay Pressure Switch Time Delay Relay Ignition Control Module (Circuit Board) Terminal Strip 3.
PAGE 8
3.0 SERVICE - Control Location, Operation, and Service (cont'd) 3.3 Service Procedures (cont'd) 3.3.
PAGE 9
Abnormal Heat Cycle Functions Interrupted Call for Heat - If the system controller call for heat is removed before the flame is recognized, the circuit board will run the venter motor for the post purge period and de-energize all outputs. If the call for heat is removed after successful ignition, the circuit board will de-energize the gas valve and run the venter motor through post purge.
PAGE 10
3.0 SERVICE - Control Location, Operation, and Service (cont'd) 3.3 Service Procedures (cont'd) 3.3.3 Combustion Air Proving Switch Pressure Switch TABLE 2 - Pressure Switch Setpoints (sea level) 3.3.2 Ignition System (cont'd) matically reset after one hour. Lockout may be manually reset by removing power from the circuit board for more than one second or removing the call for heat for more than one and less than 20 seconds.
PAGE 11
3.3.5 Flame Rollout Switch 3.3.6 Venter Motor and Wheel Assembly Complete Venter Motor and Wheel Assembly Size 150, P/N 174010 Sizes 200, 250, 300, P/N 162895 Sizes 350 and 400, P/N 164542 Refer to Parts Form P-CAUA for components. Function: The flame rollout switch is a temperature-activated manually reset, limit switch. The switch is mounted on the side of the burner box in a position that senses temperature in a central horizontal location at the rear of the burner assembly.
PAGE 12
3.0 SERVICE - Control Location, Operation, and Service (cont'd) 3.3 Service Procedures (cont'd) 3.3.7 Transformer 40VA Transformer in the Heater Electrical Box, P/N 164328 40VA Transformer in the Optional Mixing Box, P/N 103497 3.3.8 Blower Motor and Drive Function: The 40VA transformer reduces the supply voltage to a 24-volt circuit in order to operate the 24-volt controls. Transformer Check (requires a volt meter): To verify the 24-volt circuit, check the operation of the transformer.
PAGE 13
Modulating Damper Motor, P/N 196302 with Logic Module Potentiometer Modulating Damper Motor with Logic Module Function: The modulating damper motor actuates the dampers in response to enthalpy controls for cooling or a mixed air controller for heating. Outside air dampers close when the heater shuts down. Service: There is no service required other than external cleaning. If the motor or module needs replaced, replace with identical parts.
PAGE 14
3.0 SERVICE - Control Location, Operation, and Service (cont'd) 3.3 Service Procedures (cont'd) Mixing Motor Control Option on Operating Box Description Option W.D.
PAGE 15
IMPORTANT: When using a multimeter to troubleshoot the 24 volt circuit, place the meter’s test leads into the 5 or 9 pin connectors located on the ignition control. Do not remove connectors or terminals from the electrical components. Doing so can result in misinterpreted readings due to the ignition control board’s fault mode monitoring circuits.
PAGE 16
3.0 SERVICE - Control Location, Operation, and Service (cont'd) General Troubleshooting (cont'd) PROBLEM Burners cycle on and off (cont'd) PROBABLE CAUSE 4. Faulty integrated ignition control module 5. Faulty combustion air proving switch. 6. Flame sensor grounded 7. Cracked ceramic at sensor 8. Incorrect polarity. No heat (Heater Operating) 1. Incorrect manifold pressure or orifices. 2. Cycling on limit control. 3. Improper thermostat location or adjustment. Cold air delivered 1.