Bryant 350MAV user manual A02204b

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11NO PREVIOUS CODE – Stored codes are erased after 72 hours. On RED LED boards stored status codes can also be

erased whenever power (115V or 24V) is interrupted. Run system through a heating or cooling cycle to check system.

12 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 closed) or when (R-W opens) during the blower on-delay period.

13LIMIT CIRCUIT LOCKOUT – Lockout occurs if the limit or flame rollout switch is open longer than 3 minutes. Control will auto-reset after 3 hours. See code 33.

14IGNITION LOCKOUT – System failed to ignite gas and prove flame in 4 attempts.

Control will auto-reset after 3 hours. See status code 34.

21GAS HEATING LOCKOUT – 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.

22ABNORMAL 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.

23 PRESSURE SWITCH DID NOT OPEN

31PRESSURE SWITCH DID NOT CLOSE OR REOPENED – If open longer than 5 minutes, inducer shuts off for 15 minutes before retry. If opens during blower on- delay period, blower will come on for the selected blower off-delay. Check for:

-Proper vent sizing.

-Low inducer voltage (115V).

-Low inlet gas pressure (if LGPS used).

-Inadequate combustion air supply.

-Disconnected or obstructed pressure tubing.

-Defective inducer motor.

-Defective pressure switch.

-Excessive wind.

-Restricted vent.

33 LIMIT CIRCUIT FAULT – Indicates the
limit or flame rollout switch is open. Blower
will run for 4 minutes or until open switch
remakes whichever is longer. If open
longer than 3 minutes, code changes to
lockout #13. If open less than 3 min.
status code #33 continues to flash until
blower shuts off. Flame rollout switch
requires manual reset. Check for:
- Dirty filter or restricted duct system.
-	Loose blower wheel.
- Defective switch or connections.
- Defective blower motor or capacitor.
- Inadequate combustion air supply
	(flame rollout switch open).
-	Restricted vent.
-	Proper vent sizing.
-	Excessive wind.
-	Blower motor on incorrect speed tap.
-	Input rate to furnace set too high.
34 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
#14 occurs. If flame signal is lost during
the blower on-delay period, blower will

NO

YES

Unplug igniter harness from control and initiate another component test sequence. Check for 115V between pin 1 and NEUTRAL-L2 on the control. Was 115V present for the 15 second period?

Reconnect the R thermostat lead and set thermostat to call for heat. Connect voltmeter across gas valve connections. Does gas valve receive 24V?

YES

Does gas valve open and allow gas to flow?

YES

Do the main burners ignite?

YES

Do the main burners stay on?

NO

Repeat call for heat and check flame sensor current during trial for ignition period. Is the DC microamps below 0.5?

YES

45CONTROL CIRCUITRY LOCKOUT Auto-reset after 1 hour lockout due to:

-Flame circuit failure.

- Gas valve relay stuck open.

-Software check error.

Reset power to clear lockout. Replace control if code repeats.

NO

Replace furnace control.

YES	Check for continuity in the harness and igniter.
	Replace defective component.
NO
	Check connections. If OK, replace control.
	Check that all gas valves are turned on.
	Replace valve.
	Check for:
NO
	- Inadequate flame carryover or rough
	ignition.
NO	- Low inlet gas pressure.
	- Proper firing rate.
	- Check for air leakage around igniter bracket.
YES	Allow blower to come on and repeat test to
	check for intermittent operation.
NO	Check connections and retry. If current is
	near typical value (4.0-6.0 nominal) and
	burners will not stay on, replace control.

Check for:

- Obstructed pressure tube.

- Pressure switch stuck closed.

24 SECONDARY VOLTAGE FUSE IS OPEN

Check for:

- Short circuit in secondary voltage (24V)

wiring including thermostat leads.

Disconnect thermostat leads to isolate

short circuit.

come on for the selected blower off-delay.

Check the following items first before

proceeding 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.

To determine whether the problem is in

the gas valve, igniter, or flame sensor the

system can be operated in the component

test mode to check the igniter. First

remove the R thermostat connection from

the control and initiate the component

test sequence. Does the igniter glow

orange/white by the end of the 15 second

warm-up period?

Clean flame sensor with fine steel wool and recheck current. Nominal current is 4.0 to 6.0 microamps.

Is current near typical value?

YES

Will main burners ignite and stay on?

YES

Fixed.

NO	Replace electrode.
NO	Replace furnace control.

A02204b