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Douglas, HVAC Technician
Category: HVAC
Satisfied Customers: 3089
Experience:  Manufacture Rep for Major Brand, Technical Trainer, NATE
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my rheem classic 90 gas heater keeps shutting down after about

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my rheem classic 90 gas heater keeps shutting down after about 5. min any sugestions
Hi, I'm Douglas and I am here to help you resolve problems with your heating and cooling equipment.

If you can access the furnace, take both doors off. Where control board is, is a door switch that must be depressed when the door is on. Press that in and watch the sequence of operation and let it run keeping the door switch in. When the furnace shuts off, it may start blinking a code. Tell me what the little green and yellow lights are doing.

Customer: replied 6 years ago.

ok on my way to do it now....standby please


ok, if you think of it, get the model number from the furnace. It's on a tag in the burner compartment... usually on the right wall... the rating plate.
Customer: replied 6 years ago.



the model # rgrj-06emaes

the heater fired up the green led was on it ran, the blower came on ran for aprox. 4 min then kickes off. it fired up again then stoped and the green led started to flash.

Good... now all we need to do is count the green flashes between pauses. If it is 1, there is a like a 1-2 second pause between flashes. Do you recall how many times it was flashing? Is there an XXXXX XXXXXght on that board? (depends on the vintage).
Did that model have a spark ignition or a hot surface ignition? (Again depends on the vintage). Hot surface would be a bright orange glow. Did you see the burners come on when it ran?
Customer: replied 6 years ago.

yes, there is an XXXXX XXXXXght on the bord it did not flash i counted 31 flashes at about 1.5 seconds between flasshes. the flashes were steady. it didnt stop after 31 i just stopped counting should i go back and count till it stops?


i saw the bright orange glow.

Ok... let go of the switch so the power is off... On the, I think, left side, there may be an orange wire leading to a flame sensor. It's a single rod that sits out between the burner and the heat exchanger connected to a porcelin holder. FInd a piece of steel wool, a crispy dollar bill or a dry scotch brite pad and clean that flame sensor. You want to clean it as if you are sanding it clean but dont use sand paper... After you are done, try it again.

If you need to remove it, it's a 1/4 hex screw but you may be able to use a flat head.

I am about to jump on a flight. Let me know how that goes. If it works, great, you are all set and you can click accpet. If not, I will check as soon as I land for a reply and we'll pick up there.
Douglas and other HVAC Specialists are ready to help you
I assumed that took care of it. I do owe a little explanation.

The flame rod converts a potential AC voltage to a DC current through the flame to ground. Many electrons pass through the flame to ground (the burner) but few return when the sine wave reverses. This converts the AC voltage to a very minute DC current which tells the control there is flame. A little dirt on the rod can mess this up. The reason we dont use sand paper, is because it leaves small scratches that can collect duct faster next time and moreover sand paper leaves behind.... sand particles which of course when heated with a flame becomes glass and glass as you may know, is a good electric insulator...

So there you have it. If that worked. Just make cleaning the flame rod a fall routine so you dont find yourself without heat as a result of a dirty flame rod. You have a good furnace there, it will take care of you.

Thanks again, and if you need anything, just ask for Doug