bryce

I have a ten twelve year old furnace a rheem criterion two. The problem is the igniter never comes on. I bopught a new one and still nothing. It's only gettin about 8 volts. Does anyone know what it's suppose to be and if a transformer replacement might be ther problem? If I wait about 30 or 40 seconds I can light the furnace with a candle lighter. Otherwise it just eventually shuts off. help.

yuri

It is a 120 volt igniter and the transformer is not the problem. Sounds like the circuit board is faulty. The fact that the main valve opens means all the safeties are proven so the only thing left is the circuit board. Very remote chance that the wiring harness from the igniter is broken. You would have to trace the wires back to the board and check with an ohmeter. 99.5% sure it is the board is faulty. I have replaced several of them.

bryce

Thank you so much for some direction.

pcardout

My advice may help you if the previous does not -- and it may help others.

I have TWO Rheem Criterion II Natural Gas furnaces in my home. Each of them has three protective switches in the upper compartment (near the flames). They may be called flame switches, or thermal switches. Regardless, they are little buttons with two terminals and when they are
"protecting" presumably from being too hot, they open the connection between the terminals. You push a red button on the back to reset them.

On one furnace, after about five years, the buttons started opening, and I reset them a couple times. Then they got to the point where they could not be reset. They were always open. I tried to find replacements, but could not. All three of these switches are connected in series. I simply jumpered over the failed ones, removing them from the circuit. It keeps my heaters going.

I don't see yellow flames or soot or anything. My view is that there is nothing wrong with my heater but that these are really cheesy switches
and end up causing a lot of "broken" furnaces that do not need to be.
My first set of switches failed in about six years. The second heater, which never gave me any trouble just lost its first switch and I had to jumper over it. That is seven years in. I am annoyed that Rheem didn't spend $5 for the switch instead of $0.25.

I'd love to hear if others are having this problem with these units. My solution is much like putting a penny in a fuse-box -- but a bit better I think because there are three of these switches and I don't take them
ALL out of the circuit. Anyway it keeps me warm till I can get it repaired.

beenthere

Those switches. Although not the greatest quality. Don't fail unless they are getting too hot.
Not having Yellow flames doesn't mean that the heat exchangers aren't restricted. Nor that its not producing excessive CO. You have a problem that they went out.
And it should be found, and corrected before some real harm/damage is done to your house.

I don't even jump them out for a night untill I get a replacement switch. Too unsafe.


But in the Op's case. Its not those switches that are causing it not to heat up the ignitor.

pcardout

Dear Been there --

Thanks for the advice. All the competent HVAC repair folk live 90 miles away in Albuquerque. The jumpering trick is good to know when your furnace goes out on a cold Friday afternoon -- and I thought it could be helpful for more DIYers to know about it.

I am having trouble understanding what could be wrong with my installations. One is in a relatively small closet. The other is in a big closet with a large plenum beneath -- plenty of ventilation. The small closet installation might possibly be too confined, though it too has a nice plenum beneath. My thought was that those switches have a natural life-time -- which is a few years. I also don't understand
why only one of three switches should fail if there is a real problem.

Nonetheless, as I posted I thought I might look like I was ignoring a real problem -- which is certainly not my intent.
I'll take your advice and get a pro to look at these.
In the meantime -- I recall trying to buy replacement switches on my own a year ago -- and the Rheem site won't sell to ordinary homeowners. Do you know a place to buy these fiddling types of furnace parts?

yuri

You need to have LOTS of air for proper combustion. The plenum size has nothing to do with combustion air. Those swicthes should NEVER ever trip unless somethng is SERIOUSLY wrong. The gas valve may be overfirng (get the tech to check the manifold pressure). You may be short of combustion air or have a problem with the venting and chimney (may be plugging up). Jumpering those switches is a disaster waiting to happen and I have seen a few of those. Years ago we had a rooming house with a collapsed chimney. 2 people died and several are in a permanent coma. Get it checked properly and get 2 CO detectors for your house. 1 in your bedroom.

beenthere

I buy my Parts from Rheem distributor. So I don't know whaere you cn get parts.

If your burning LP.
You can have a sooted up cell that the inducer isn't able to pull the gas and air through. Or an orifice that has dirt in it, and have a flame impingement near the beginning of the cell. And also could have a cracked heat exchanger cell, that is only effecting that roll out.


These are just some of the reasons that jumping that roll out on a Sunday is BAD idea. Its possible to give you and your family CO poisoning without realizing it.

Those switches, go bad from either tripping too often. Or being near their trip temp too often.