Comfortmaker F80CTL User Manual

F80CTL & G80CTL: Installation, Start–Up, Operating and Service and Maintenance Instructions
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
47
A190159
Fig. 54 – Troubleshooting Guide
1 + 2 BLOWER ON AFTER POWER UP –
(115V OR 24V) – Normal operation. Blower runs for 90 seconds, if unit is powered up during a call for heat (R- W/W1 closed) or when (R-W/W1 opens) during the blower on-delay period.
6 + 1 IGNITION LOCKOUT – System
failed to ignite gas and prove flame in 4 attempts. Control will auto-reset after 3 hours. Refer to status code #6.
5 ABNORMAL FLAME-PROVING SIGNAL
Flame is proved while gas valve is de- energized. Inducer will run until fault is cleared. Check for: - Stuck open or leaky gas valve.
2 PRESSURE SWITCH DID NOT OPEN –
Check for:
- Obstructed pressure tube. - Pressure switch stuck closed.
3 LOW-HEAT PRESSURE SWITCH DID
NOT CLOSE OR REOPENED – If opens during blower on-delay period, blower will come on for the selected blower off-delay. If open longer than 5 minutes inducer shuts off for 15 minutes before retry. Check for: - Proper vent sizing. - Low inlet gas pressure (if LGPS used). - Inadequate combustion air supply. - Disconnected or obstructed pressure
tubing.
- Defective or miswired pressure switches - Excessive wind. - Restricted vent. - Defective Inducer motor. - Low inducer volta
g
e
(
115 VAC
)
4 LIMIT CIRCUIT FAULT – Indicates the
limit, draft safeguard, flame rollout, or blocked vent switch (if used) is open or the furnace is operating in high-heat only mode due to 2 successive low-heat limit trips. Blower will run for 4 min. or until open switch remakes whichever is longer. If open longer than 3 min., code changes to lockout #7. If open less than 3 min. status code #4 continues to flash until blower shuts off. Flame rollout and blocked vent switch require manual reset. Check for:
- Restricted vent.
- Loose blower wheel.
- Defective switch or connections. - Proper vent sizing. - Dirty filter or restricted duct system. - Excessive wind. - Inadequate combustion air supply.
(Flame rollout switch open)
- Blower motor not operating
To determine whether the problem is in the gas valve, igniter, or flame sensor the system can be operated in component test mode. To check the igniter remove the R thermostat connection from the control, reset power, and put setup switch SW1-6 in the ON position to start the
component test. Does the igniter glow orange/white by the end of the 15 second warm- up period?
Unplug igniter harness from control and repeat component test by turning setup switch SW1-6 OFF and then back ON. Check for 115V between pin 3 and NEUTRAL-L2 on the control. Was 115V present for the 15 second period?
Check connections and retry. If current is near typical value (4.0-6.0 nominal) and burners will not stay on, repeat check in high-heat. If burners will still not stay on replace control. If burners operate in high-heat then switch to low- heat, check manifold pressure. If OK, check burner carryover and flame sensor location.
Clean flame sensor with fine steel wool and recheck current. Nominal current is 4.0 to 6.0 microamps.
Is current near typical value?
Replace flame sensor.
Will main burners ignite and stay on? Replace furnace control. Fixed.
NO YES
YES YES
NO NO
Replace furnace control. Check for continuity in the harness and igniter. Replace defective component.
Reconnect the R thermostat lead and set thermostat to call for heat. Connect voltmeter across gas valve connections. Does gas valve receive 24V? Does gas valve open and allow gas to flow?
Do the main burners ignite? Do the main burners stay on?
Allow blower to come on and repeat test to check for intermittent operation.
Check that all gas valves are turned on. Replace valve. Check connections. If OK, replace control.
Check for: - Inadequate flame carryover
or rough ignition.
- Low inlet gas pressure. - Proper firing rate.
Repeat call for heat and check flame sensor current during trial for ignition period. Is the DC microamps below 0.5?
YES
YES
YES YES
YES NO NO
NO
NO NO NO
6 IGNITION PROVING FAILURE – If flame is
not sensed during the trial for ignition period, the control will repeat the ignition sequence 3 more times before lockout #6 + 1 occurs. If flame signal is lost during the blower on-delay period, blower will come on for the selected blower off-delay. Check the following before going to the next step. - Gas valve turned off.
- Manual shut-off valve.
- Green/Yellow wire MUST be connected
to furnace sheet metal.
- Flame sensor must not be grounded.
9 HIGH-HEAT PRESSURE SWITCH OR
RELAY DID NOT CLOSE OR REOPENED Check for: - Control relay may be defective. - Gas valve is miswired. - Refer to status code #3.
10 POLARITY – Check for correct line voltage
polarity. If units are twinned, check for proper low-voltage (24V) transformer phasing.
7 LIMIT CIRCUIT LOCKOUT – Lockout
occurs if the limit, draft safeguard, flame rollout, or blocked vent switch (if used) is open longer than 3 minutes or 10 successive limit trips occurred during high- heat. Control will auto-reset after 3 hours. Refer to status code #4.
8 GAS HEATING LOCKOUT – Control will
NOT auto reset. Turn off power and wait 5 minutes to retry. Check for: - Stuck closed gas valve relay on control. - Miswire or short to gas valve wire.
2 + 5 INVALID MODEL SELECTION OR SETUP
ERROR – If status code 2 + 5 only flashes 4 times on power-up the control is missing its model plug PL4 and is defaulting to the model selection stored in memory. If status code 2 + 5 flashes continuously it could indicate any of the following: - Model plug PL4 is missing and there is no
valid model stored in permanent memory. This will happen if you forget to install the model plug PL4 on a service replacement control.
- Thermostat call with SW1-1 ON.
- Thermostat call with SW1-6 ON. - SW1-1 and SW1-6 both ON. - Two different furnace models twinned. - If replacing a control, be sure to use
correct version (V##) located on control board) Models supported should be listed
NOTE: NUMBER IN UPPER LEFT HAND CORNER REPRESENTS FLASH CODE
4 + 1 BLOWER MOTOR FAULT –
indicates blower failed to reach 250 RPM or the blower failed to communicate within the prescribed time limits. 30 seconds after being turned ON or 10 seconds during steady-safe operation.
1 + 5 BLOWER MOTOR LOCKOUT – Indicates
the blower failed to reach 250 RPM or the
blower failed to communicate within 30 seconds
after being turned ON in 2 successive heating cycles. Control will auto reset after 3 hours. Refer to status code 4+1.

Comfortmaker F80CTL Specifications

General

Brand	Comfortmaker
Model	F80CTL
Category	Furnace
Language	English