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Douglas, HVAC Technician
Category: HVAC
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Experience:  Manufacture Rep for Major Brand, Technical Trainer, NATE
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My Rheem RGUH-05EAVER Criterion ii natural gas furnace is not

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My Rheem RGUH-05EAVER Criterion ii natural gas furnace is not working. This furnace is in my garage and worked fine 6 months ago when last used, but just tried today and no heat. I have done a bit of looking online and looking at the furnace. The draft fan motor comes on, the two green lights on the board are on solid. The spark ignitor never sparks. The main blower will kick on after a minute or so, runs for a few minutes, then shuts off. The draft motor continues to run and then eventually shuts off. The yellow light never comes on. I checked the pressure limit switch and it seems to be working correction. Only time I receive a flashing light is when I had disconnected one of the pressure switch wires. Otherwise I did a continuity test on the switch which was fine. I think checked the voltage of the switch and showing 26 volts AC on one terminal and then after the vent motor runs for a few seconds, the other terminal has 26 volts which is a brown wire. I checked that back to the circuit board and show the same thing at the board. This is a spark ignition system. I checked the voltage going into the ignitor wire, and it shows nothing. Is this a board problem or can something else be causing it?

Hi, I'm Douglas and I am here to help you resolve problems with your heating and cooling equipment.


The yellow light is a flame proving light, so it wont come on until there is flame.


Let it attempt to cycle a few times without interuption. Does one of the green LED's blink a code? (1 blink, 2, 3, 4, 5)... there is about a 2 second pause between codes if any.

Customer: replied 5 years ago.
I let it cycle for 3 times. It did not do it by itself, so in between cycles I had to turn the thermostat off and then back on to make it cycle. The lights stay on solid green, both lights. They never blink, just on solid. On the model number, I had a U and V reversed if it matters. The correct is RGVH-05EAUER. Also I see that it has a sticker on the front saying this is a quality assurance model and the main board has a QAE sticker on it, just as an FYI.

so the inducer came on with a call for heat, and a while later the blower came on with no fault code? Ok... its probably a failed ingition, it would try 4 times and display a 1 fault.


So thats sounds right so far. But If I am correct the RGVH has a hot surface ignitor, not a spark. The ignitor is by the right burner, does it have an orange wire or two white wires leading to the ignitor?

Customer: replied 5 years ago.
It has one orange wire. But I checked the voltage with and without the orange wire plugged in. With it plugged in, zero voltage. With it out, showed around 55 volts AC. I measured the resistance of the ignitor, and it showed 0 and had full continuity.

Ok, I wouldnt try to measure that voltage if its a spark ignitor, its in the 10000vdc range.


Just to be sure, Can you give me the first two letters of the serial number? I want to make sure we are looking a the same control. The RGVH should have had hot surface. I believe you but want to grab the right documents. The first two letters of the serial number will tell me which controls are in it.


Also, there was an RGUH, you are sure it's a V?

Customer: replied 5 years ago.
It could be a U. I was comparing it to some other letters on the sticker and after it looked at it again, it looked like a V.
Model, as best as I can read it.

DL5D302 F4494 3670
Ok bear with me.

I see a DJ which is intermitant pilot, I dont see a DL but all but the DJ were Hot Surface Ignitor. In the DJ, the spark lights a pilot, not the burners directly. Being a 94 model it's definately a RGVH, not a RGUH.


Ok... So is there a pilot light that gets lit every time? If so, is there a 1/4" aluminum tube leading to the pilot?

Customer: replied 5 years ago.
Yes it does have the aluminum tube running over to the gas valve.

Ok... so I got the right one. Great, since that was a limited production run, I dont see a schematic.


I hate to ask this, but if you remove the blower door and look on the inside for a schematic, is there a number in the bottom maybe starts 92-????

Customer: replied 5 years ago.
I had already looked on the inside of the blower door, and there is nothing, not stickers, diagrams, nothing.

Hmmm must have been swiped or fell off.


Ok... we'll do our best from here.


The orange wire must lead back to the spark generator. Is this part of the furnace control board or is it a seperate device?

Customer: replied 5 years ago.
It is part of the furnace control board, a round device mounted on it.
The below eBay link shows it, it is the blue round unit on the attached.
The board number shows 62-26000-01

Ok those spark generators dont often go bad, but anythings possible.


If you have a piece of insulated wire, you could attach one end to ground and the other end strip back a 1/4" or so, hold it 1/4" from the needle and call for heat, if after the inducer runs for about 20 seconds on a call for heat, you dont see a spark jump from the needle to the tip of the wire then likely the generator is corrupt (new board). If it does jump, then your ignitor is faulty and is dumping to ground along the orange wire or a cracked or porus ceramic insulator.


If another safety were playing into this, you would get a fault such as 2 blinks on the green or 3 blinks (pressure switch or limit switch).


I think the rollout switches are in series with the main switch. The aux limit in the blower should be breaking voltage to the gas valve if it were opening but that wouldnt turn the spark off.



Customer: replied 5 years ago.
Here is what I did. I took a piece of insulated 14 gauge wire and stripped both ends. I grounded one end and then held the wire close to the metal terminal on the end of the blue circle devise on the main circuit board. I ran through a couple of runs with the furnace, and it never sparked. But I did actually touch the terminal a couple of times holding it and the yellow light flashed on and off then flickered some, not sure what that means. Only other thing I noticed is at the end of one of the runs, or I should say trying to run, the middle green light went out. I did wait to see if it would start flashing a code or anything, but it did not. FYI I plugged the orange wire again and did a run and the two greens were just on again and no flashing, no nothing.
Also, I did find a decal on the front of the lower panel, it was not on the inside. It has the below number if that helps. It was not a wiring diagram, but something about to start it.
It sure sounds like the spark generator is kaput which means a new board. If you are lucky you'll be able to find that board on line but I suggest you call the online retailer before purchasing to make sure they actually have their hands on it because its no longer available from Rheem and if thats where they were going to get it, they wont.

Seems you showed an E-bay seller, use the ask a question form to see if he has it in his own inventory. You dont need someone taking your money and then telling you it's on back order (again, its obsolete with no replacement).
Douglas and 3 other HVAC Specialists are ready to help you
Customer: replied 5 years ago.
I have ordered the new board and should be here by the end of the week. Once installed and working, no problem accepting answer.