For Northernheat
Still getting code of 8 led flashes. Have checked the flame sensor not cracked or touching anything and is in the flame. The only time that it seems to happen is when the temp gets colder like 32/34 after being 38/40. The LED error code states Internal control fault Micorprocessor has sensed an error in the software or hardware. If error code is not cleared by reseting unit power, replace the IGC. But it does reset when the power is turned off and back on . And works okay until the temp changes colder.

I don't see where you told me exactly what 8 flash code says on the diagnostic chart. If it is a flame rectifaction error be sure polarity to furnace is correct and the furnace is well grounded to the main electrical panel.

STATUS CODES: LED Explanation On (continuous) Normal Operation Off Hardware Failure:

Looks like a circuit board according to this legend. Replace IGC

1 Flash Modified Indoor Blower On or Off Delay.
2 Flashes Limit Switch Fault 3 Flashes Flame Sensor Fault.
4 Flashes 4 consecutive limit switches trips.
5 Flashes Ignition Lock Out.
6 Flashes Induced Draft Motor Fault.
7 Flashes Flame Roll Out Fault.
8 Flashes Internal Control Fault • CODE.
9 ?•New code “internal Software Fault” •Found on boards made after may 2000 •Does not replace code 8 “internal control fault”
• Will lock the board out for one hour or until control voltage is reset. * CODE 9 ? Possible cause: spark ignition wire routed to close to other wires • • Solution: route the spark wire away from any other wires. If code reoccurs after rerouting wire replace Circuit board.


Bryant Carrier Furnace Control Board LH33WP003





Replaces Circuit Board Part Numbers:

LH33WP003 LH33WP003A, CARLH33WP003A.

IGC Circuit Board 1 Stage Heating per board 1 Fan Speed for both Heating & Cooling 1 Speed Induced Draft Motor.

LED for Status Codes Self Adjustable Blower on Delay Self Adjustable blower off delay.
Sequence of Operationthermostat energizes W on circuit board.
Induced Draft Motor is energized. Gas Valve energized, Electrode Sparks for 5 seconds, burners lights, flame sensor proves flame in 2 seconds.
45 seconds later the Indoor Fan Motor is energized.
Next unit operates until demand is satisfied. Call for heat is satisfied the main gas valve & induced draft motor are de-energized.
Next 45 seconds later the indoor blower motor is de-energized. BLOWER ON DELAY: •Standard on delay 45.
Delay is reduced by 5 seconds, for each limit switch trip that occurs before the fan comes on.
Max on delay is 45 seconds.
BLOWER OFF DELAY:•Standard off delay 45 seconds.
Delay extended by 15 seconds after each limit switch trip that occurs after fan shuts down • •Max off delay 3 minutes.
Anti Short-Cycle ProtectionHeating runs for at least one minute after any momentary call for heat!

And this is why I don't like or sell Carrier. Over engineered and not that reliable.

((And this is why I don't like or sell Carrier. Over engineered and not that reliable.))

I agree but they do generate good service calls. $$

I really should not say anything bad about Carrier/Bryant. They donate equipment and we also test for them. They over engineer for safety they say.

I will have to say that Goodman uses off the shelf parts and that makes them simple and cheaper to repair. For a cheap piece of equipment they work OK.

I was thinking 8 or 9 was rf interference on the older boards. Do you have a new garage door opener or alarm on the car, construction site next door?

I had a similar problem (as have many others) and hope this information helps. --John


Symptom:

Intermittent furnace lockout with Internal Control Fault (8 flashes), sometimes accompanied by the "modified fan blower delay" fault (1 flash). Problem occurs especially when the temperature falls below 32 degrees. Checked rollout switches and flame sensors, no problem.

Cause:

Excessive vibration triggering the relays on the Integrated Control Panel, which cause the internal control fault (usually the vibration can be felt by touch on any part of the unit)

Temporary Fix:

Dampen the vibration to the control panel using high-temp flame-resistant padding.

Permanent Fix:

Vibration most likely due to imbalanced blower wheel (cage wheel inside the blower that pushes flame exhaust out of the unit). Replace blower wheel.