Premature Burner Shut-Off - Rheem Gas Furnace RGTA-07EMAES

All2kool

I am looking for some advice on my Rheem Gas Furnace RGTA-07EMAES, S/N EJ5D702F150100415. If I read the S/N correctly, the unit was made in the 15th week of 2001.

It recently starting shutting off the burner mid-cycle but will attempt to re-light. Sometimes it re-lights, sometimes it does not. After 3 failed attempts to re-light, the system goes into 'lockout mode' and won't attempt to reignite for an hour unless I reset the power from the breaker box or open the top panel. The LED error code of 1 flash indicates 'ignition failure' after these 3 failed attempts. This is the only error code displayed.

I replaced the Flame Sensor (was careful and did not touch it) with a new Rheem part but this hasn't solved the issue. The original Honeywell Gas Valve was also replaced with a direct replacement as it was making a horrible clicking/clanking noise as the burner would pulse and 'flame out' like a jet engine. There is no rhyme or reason to this intermittent function.

The Honeywell thermostat is not the issue as it does begin and end the heat cycle as designed when the heat cycle has not been interrupted.

I've had two techs here in the last month prior to replacing the Flame Sensor and Gas Valve but the problem could not be recreated in their presence so nothing was done. The first tech noted a slight burning on one of the resistors. I pointed it out to the 2nd tech and he mentioned he'd seen that before. I've included a photo but the flash from the camera somewhat makes it less noticeable. It's the 2nd blue resistor from the top.


Am I correct in assuming that I really should replace the Circuit Board to resolve my issue?

Thanks in advance for any help.

HVACNUT

Keep doing that way and you'll have a brand new 2001 furnace in no time.

Things need to be actually checked. Was a combustion test done? LP or natural gas? What's the manifold and lockup pressures. Does manifold pressure hold while other gas appliances are running? This is draft induced? What's the amp draw on the inducer motor? What the reading on the pressure switch(es)? The flame sensor was replaced, so what's the microamps reading? Is it within Rheem specs?

Were these techs with the same company? If so, it might be time for a call to the service manager. 

pedmec

The sequence that you should be going thru after the pressure switch has proved is roughly a 10 second per-purge (different manufacturers, different times. then you should have a 30 second warm up period for the HSI to get hot. If it is good you should see it glow. Then you should hear a click from the gas valve indicating that it has received voltage to open. If you don't get the HSI to warm-up you don't get flame. Because this part of the sequence is time based the gas valve will only be energized for less than 4 seconds.

109A_5

Hello @All2kool,
Mild discoloration of the circuit board and/or power resistors is common and just a sign of poor or marginal engineering, since it could be avoided, but the product may cost a bit more.

As much as a poor solder joint or any other age related dilapidation of the control board may be causing the issue, it could be something else and good logical troubleshooting should be utilized as mentioned above.

Any loose connections ? Grounds intact and tight ? The flame detection sensing typically needs a good ground for proper operation.

WMno57

Check all the air vents in the house. Supply and return. Open? Not blocked by furniture? Not obstructed with dust? Replace the air filter. It may be overheating due to poor airflow. May or may not be the problem. If that doesn't fix it, someone skilled needs to troubleshoot and identify what part needs to be replaced.
Routine maintenance is always worth doing.
Throwing parts at an unidentified problem usually not worth doing.

worldclasshvac

Pretty common to have boards act up on older furnaces.  Chances are you are dropping voltage to the gas valve randomly and it drops the flame and gives that code.  I have changed many a ghost problem board and usually are successful.  

yellowdog

It always makes me laugh when someone changes the flame rod when they have a lack of ignition.