No heat from Rheem furnace

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  #1  
Old 12-24-16, 07:33 AM
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No heat from Rheem furnace

Merry Christmas everyone!

My furnace quit heating abruptly.
Rheem Criterion II.
Draft inducer starts, ignitor glows. Burners fire up and stop almost immediately.
The furnace then blows for while, like it's heating without any flames, then shuts down.

I have a programmable battery thermostat if that matters.
 
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Old 12-24-16, 07:56 AM
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Bummer, I'm sure you could do without that Christmas present

Are there any LED's on the board giving a flash code? Could be a flame sensor issue, also could be a rollout sensor or overtemp sensor tripping; check for any manual reset sensors. And check for restricted exhaust or intake. If it's a rod type flame sensor try cleaning it gently.
 
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Old 12-24-16, 08:18 AM
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H,
It sounds like you may have a dirty flame sensor. It is a rod on a piece of porcelain that senses the flame and tells the gas valve everything is OK. It looks like a white porcelain with a single wire connection to it fastened with 1 or 2 screws to the furnace.

Shut your power off and remove it being careful not to touch the rod with your hands and clean with some 0000 steel wool or the finest you have. Try not to use anything real abrasive. Reinstall and start the furnace.

With the limited information this is a good place to start.

Hope this helps a little.
 
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Old 12-24-16, 08:40 AM
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Thanks guys, Furnace is working. I work with wood so had a lot of steel wool.

I'm curious. If a battery operated thermostat fails to operate, will it revert/operate just like a normal one or does it need replaced immediately.
 
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Old 12-24-16, 09:21 AM
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Good deal!

Usually the thermostat only uses the batteries during power outages and is powered by the 24 volts from the furnace most of the time. If you don't replace the batteries you do run the risk of losing any programming like setbacks, Time of day, etc.
 
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Old 12-24-16, 10:00 AM
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Most battery operated stats will jitter when the batteries get low as the batteries are used to operate control relays.
 
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Old 12-25-16, 08:12 AM
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I ran out of luck
I cleaned the flame sensor. Now the furnace will blow and not shut off (with no flame).
The only way to keep it from blowing is to unplug it, thermostat has no effect.

I have a feeling I need to wait till I can call someone out.

I see Rollouts I think, maybe three? They have wires, a flat face that feels fragile, and a little peg at the back.
No idea how to reset them.
 
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Old 12-25-16, 08:59 AM
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The rollouts can get fragile with heat and age. An open limit switch will keep the blower running.

Take an ohmmeter on Rx1 scale and check each switch. They should show show continuity...... a dead short.

The little peg on the rollout switches gets pushed straight in until it clicks. Check them before trying to reset.

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  #9  
Old 12-25-16, 09:28 AM
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All three switches have continuity with unit unplugged.
 
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Old 12-26-16, 08:41 AM
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I'm still troubleshooting since I probably can't get someone out.

I removed the Programmable stat, mounting plate and terminal block is still on the wall.
Removed the heat wire (blue) from the blower, blower still runs.
The only stat wire on the control board that has voltage is red, and I think that's correct. (R up and Grn down).
I think it's not the thermostat or the wires?

Edit: I discovered it's the draft inducer motor than won't shut off, not the blower.
The chimney isn't blocked.
 

Last edited by Handyone; 12-26-16 at 09:50 AM.
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