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I have tow of these in my own home and they have worked flawlessly for three years. Installed a bunch of 'em over the years and never had a no heat call on any of them.

All I can suggest from my travails with other furnaces is to go through the electrical supply from end to end and make sure that all the connections (ground, neutral and line) are clean and tight and phased properly. This includes the main lugs at the input of the mains panel! Found that some of these can be loose and this is all a "computer" on a FAU board needs to cause wonky operation... Your problem sounds suspiciously like this may be a cause. Also look for potential (voltage) between the neutral and ground as this drives them nutz and is an indication of poor grounding. IF this does not solve the issue I'd then resort to a board change out.

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I had one that took out the stat a few times. Changed out the board and have had no issues since.


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Check for proper ground, had a ruud lock out from that after a week of running.

Are there any faults in it's history? Maybe a sticky relay on the board? I would lock out door switch so if or when it happens again I could check relays with out it resetting. I had a few inducer relays go out on Rheem mod boards.

Choke or filter on the main power feed may help.

Exact same issue with a RGFE right now. Changed the board out 2 weeks ago and same issue appeared today. Our suppliers tech is as baffled as me. I changed out the stat just see what happens but the "H" means there is a call for heat and a modulating signal. Anyone else run across this?

Nope, no fire and no ventor or fan operation. After you disconnect and re-connect power it fires up and runs with no issues. I've checked all pressure and electrical readings on 5 of these things and everything always looks good. We're being told to replace the boards but I havn't been able to get any feedback if this is the right fix or if there's some other intermittent problem. What's even more frustrating is that I can never seem to get ahold of Rheem tech support. I know rheem makes a quality product but Im starting to lean away from recommend them to customers.

Im starting to think so...lol

Twilly says Loonie did you forget we ship the seconds to Canada?

Sorry, that sucker has probably been the most reliable furnace we've sold, knock on wood.

Capitol H means you are modulating, small h means you aren't, either a wiring issue or wrong stat. But you have no fire?

Rheem modulating furnace

Hey guys,

The company I work for recently started selling the Rheem RGFE and UGFD modulating furnace. The problem is that we've been seeing some goofy stuff that Rheem can't even explain. I gotten calls for no heat anywhere from 2 days to 6 months after the install and have found a cold house with the modulating thermostat calling for heat and finding a capital H or lowercase h on the circuit board indicating that the unit is heating on low or high fire but one problem...nothing's running. Any help would be appreciated!