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I have a Rheem Criterion II Gas furnace. It is not igniting.  When I switch the thermostat to "heat" - the furnace doesn't not start.  There are 2 green lights - one is one and the other is blinking.  The filter is clean and the connections seem intact...any ideas?

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  • witchratt Dec 22, 2008

    I have the exact same problem as above and would appreciate any suggestions. Thanks!

  • witchratt Dec 22, 2008

    This is a followup to my previous post: I have also tried putting in a new thermostat and I still have the same result. Thanks again.

  • dmgarcia326 Mar 25, 2009

    I also have the same problem with the Criterion II. The ignitor sparks but won't light the pilot once in a while. Usually by the second time it will light. However, my HVAC company told me I should get it fixed. they first replaced the motherboard, which didn't solve the problem. They then replaced the gas valve, which didn't solve the problem. They then came over and "made the spark bigger." that also did not solve the problem. That tech told me that is the way these ignitors work. My furnace is less that 5 years old so is still under warranty. The parts were paid for but I had to pay $200 labor. I had them come back again after we had some extensive remodeling. The HVAC guy told me it was because there was dust from the remodeling. I am having another firm come tomorrow and clean and check it. I have thought all along if the ignitor is not starting the furnace, it is logical to me that the ignitor would be the problem. We will see what a different HVAC firm says tomorrow. I will no longer use Golden Seal that charged me, but did not fix my furnace. I feel they were just throwing parts at it. Any suggestions would be appreciated.



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Roscoe007 shouldnt speak unless he knows what he is talking about, as a heater installer i am telling you the ignitor needs to be replaced, the very fact that the ignitor does light for about 30 sec than goes out rules out any issue with the themostat, replace the ignitor!

Posted on Dec 28, 2008

  • leeCA Jan 13, 2011

    I found that the preasure switch is the problem if the igniter is not. Take the igniter in the garage and put 110 v to it-if it ignites - check the preasure switch (little round thing with the rubber hose attached. Disconnect blow and **** - should hear clicking. if not replace it - it should then work. Part is $ 27 depending on the furnace.


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Hi Welcome to
you have a Rheem Criterion ii Gas Furnace thats not ignighting if you have a digital thermostate make sure batteries are ok. Im now assuming you have the heater door on when your trying to start the furnace ,because there are safety door switches.. if you have the door on .It sounds like the thermostat is bad ,it will start then run for 30 secs and go retry exact same results..goes on for 30 secs goes off...I would say thermostat If it is digital remove it and try to resnap it in 1st. Please Remember to leave me some Positive feedback! Thankyou...

Posted on Dec 17, 2008

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Same problem
If I lose power in the middle of a burn it will do as described.
Powering down the furnace and powering it back up fixes it.
Seems like a software issue.
Rheem is hard to deal with.

Posted on Oct 20, 2009

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Any black coloring on the heat exchanger is *not* from overheating. Black is from a sooty flame caused by a mis-adjusted burner. (In fact, a sooty flame is less hot). There is an adjustable "air intake plate" for air to enter the burner where the gas enters the burner. A proper flame is made by adjusting this air opening so the proper gas/air mixture feeds into the burner. If the air vent is closed too much it produces a sooty flame.
The age of the furnace is the most important aspect, and that helpful to determine a likely condition of the heat exchanger and burners. Other than a badly adjusted flame, the main thing to watch for is a badly rusted out heat exchanger. But black does not mean rust.

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If you get no pilot at all, check to see if any gas is getting through the pilot assembly. Try a very long match or butane fire place igniter while it is sparking.

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Rheen PVW50 Hot Water Heater Making Buzzing Noise and Doesn't Light

Why is it always Rheem problems?
Every water heater problem is Rheem.
And Rheem doesn't post any service manuals, like the other two big manufacturers, AO Smith-American, and Bradford White.

Copy following link for troubleshoot by gas control valve.

Scroll up and find pressure switch heading among links.

You can install gas control valve yourself.

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We have a 10 year old Rheem PVW50 Power Vented water heater that works on gas. The last couple of days it has been giving out problems. It will not maintain hot water in the tank. I restarted it and...

The igniter is glowing, but no gas ignites?
So either the gas is entering combustion chamber and not lighting because igniter is positioned incorrectly -or- no gas is entering combustion chamber because air in gas line or bad gas control valve thermostat or gas line is clogged.
When you 'restart' the water heater, somehow you are getting gas to the burner and it is igniting.
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Identifying numbers are usually on side of gas valve.
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Here is what the book says:


(Remember to wait for purge time, 17/34 seconds, on models so equipped).

Possible causes

A. No main power

B. Faulty transformer

C. Faulty thermostat

D. Faulty limit switch

E. Faulty blower interlock switch

F. Faulty hot surface ignitor

G. Faulty ignition control


Step #1

Perform normal system checks of main power, transformer, thermostat, limit

switch, blower interlock switch, and replace faulty component.

Step #2

With power on and thermostat set at its highest position, check voltage

between "TH" and "TR" on HS780 ignition control. If 24 volts is not present

check output at transformer. If no, replace transformer. If transformer

checks out OK look at other controls in the 24 volt circuit I.E.: thermostat,

limit switch, blower interlock switch. Check for 120 volts between "neut"

(L2) and "120" (L1). Check for 120 volts at the ignitor across "IGN" and

"IGN" terminals on the HS780 ignition module. If 120 volts is present,
replace ignitor. If no, replace the 780 series module



Possible causes

A. Improper ignitor alignment

B. Faulty ignition control

C. Faulty gas valve

D. High inlet gas pressure

E. Polarity reversed

F. No earth ground


Step #1

Check for availability of gas at gas valve. Make sure the manual valve

upstream of the gas valve and the gas valve are in the full on position. Also

make sure gas is being supplied to the system at the proper pressure, too

high will lock-up the valve.

Step #2

Check proper polarity of "NEUT" and "120" on the ignition control by reversing

the wires, if reversed gas valve will not open. If this does not solve the

problem, replace wires as they were.

Step #3

Check for proper ignitor position.

Step #4

Check for a good earth ground by using a meter connected between L1

and furnace chassis. Should read 120 volts, if no, check and/or repair ignition
ground wire or ignition control mounting screws.

Step #5

Check for 24 volts at the gas valve terminals; "1" and "2" on a 7200 series,

"M" and "C" on a 7100 series, "TH" and "TR" on a 7000 series. If yes,

check wire integrity or change the gas valve. If no, change the 780 series
ignition module.

That is pretty much all of the troubleshooting required.

Thanks for choosing FixYa,

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