rheem criterion furnace will not start

[doug]

Rheem criterion gas furnace installed in 97 the problem is it will not start up. I was replacing some plumbing when I cut the wire to the thermostat, I did this thinking it belonged to the doorbell well anyway after discovering it belonged to the thermostat I spliced it back together. Now the furnace will not start up I have already checked for any fuses that would have been blown by chance the wire did touch anything. The one on the thermostat is ok the furnace does not have one on the circuit board. Here is the model # for the circuit board model 1012 925 I believe made by Honeywell. I have also tried taking a jumper wire and on the furnace put it on R and W on the circuit board when I did this the furnace did not start up so I am thinking the board is bad. Can the wire for the thermostat have killed the board by touching together or anything else?

[mdshunk]

I still think that you just blew a fuse. Your furnace has the Honeywell 9201 Integrated Furnace Control. It has two status lights. A "PWR" light and an "OK" light. If the PWR light is not lit, it's not getting 24 volts from the transformer in the furnace. Check with a meter that you have 120 volts AC going into the transformer. Then check that you have 24 volts AC coming out of the transformer. Your furnace likely also has an inline fuse holder on the 24 volt side of the transformer. Check this too. If you have 24 volts coming out of the transformer, check between the 24 volt and COM terminals in the middle of the IFC board for 24 volts. If you still have 24 volts there, you toasted the IFC. They're about 150 bucks, wholesale. Sorry...

[doug]

Thanks for the quick reply, I do not see a fuse anywhere inside this furnace or on any wire the only fuse is on the on/off switch. I need to get some batteries for my meter, so my guess its fried. I have some pic but need to figure out the upload here on this site first. There is a green and yellow light on the bottom right hand corner of the board neither one is lite.(on)

[mdshunk]

The fuse for the 24 volts will likely be a little glass fuse in an inline fuse holder like this one below. The color may be white. Don't assume the board is bad until you've done the checks with a meter. See pic:

[doug]

mdshunk, I know this sounds dumb but thier is no fuse or fuse holder to be found, I find this odd myself i have checked and rechecked the wires even on the board their is no fuse of any kind that i can see.

[mdshunk]

Sometimes furnace transformers have a breaker of sorts built on them. A little pin will pop up (sort of like the thanksgiving turkey timer). You press the pin back down to reset it. Certainly, do the meter checks when you get a battery. With both lights on the board being out, if you get 24 volts with the meter check, you do have a fried board. Remember, the door switch on the furnace must be pressed in when your doing these checks. The door switch pretty much de-energizes the whole furnace.

[doug]

will be checking things out tommorow thanks for now

[doug]

Mdshunk, it turned out to be the control transformer I was able to pick one up for $15.00 I plan on adding a in-line to this furnace everyone that I have talked too seems it odd that there is no fuse. Do I pick one of those holders up at any auto store or is it a different type, the guy I got the transformer from did not have one. Also what size amp for the fuse? I never even asked these question when I bought the transformer I guess I should have. Well thanks for all your help
Doug

[mdshunk]

Mdshunk, it turned out to be the control transformer I was able to pick one up for $15.00 I plan on adding a in-line to this furnace everyone that I have talked too seems it odd that there is no fuse. Do I pick one of those holders up at any auto store or is it a different type, the guy I got the transformer from did not have one. Also what size amp for the fuse? I never even asked these question when I bought the transformer I guess I should have. Well thanks for all your help
Doug

Good. It's pretty nice that you were able to get a 15 dollar transformer instead of a 150 dollar board. If this is your typical 40VA transformer, these normally get protected with the oddball 1-6/10 amp fuse. This is a peculiar fuse size made purposely for HVAC applications. If you can't locate one, a one amp fuse will work fine. Any fuseholder that will accomodate a 1 amp fuse will do the trick for you. Locate the fuse on the secondary of the transformer (the 24 volt side).

[doug]

yes it is a typical transformer by the way this one is not made for rheem but it does work. will pick up a fuse holder for it. my wife sure is happy now that i could fix it on my own, she was pretty upset that i cut the wire in the first place. went with out heat for 2 days because of the weekend. it was not that bad only got to 60 in the house live in utah. still winter here like where you are in.

[mdshunk]

Transformers are never replaced with the exact OEM one. These are generic, and are replaced with whatever is at hand that is big enough (wattage or v.a. wise). This will not effect the operation of your furnace one bit. Glad you're all sorted out.

[burgan]

I have a similar problem. I suspect that the 24 volt transformer sending power to my thermostat is blown. However, I am reading 120 volts on both the primary and secondary coil. Is this possible?

I am taking my readings by touching a point on each coil to ground. is this the correct way??

Thanks,

Jeff

[junkcollector]

I suspect that the 24 volt transformer sending power to my thermostat is blown. However, I am reading 120 volts on both the primary and secondary coil. Is this possible?

Anything is possible. It could happen if the transformer was shorted, overheated, and the insulation on the windings was in any way compromised, and the 120 v primary coil was making contact with the secondary coil. Unlikely but possible.


I am taking my readings by touching a point on each coil to ground. is this the correct way??

I don't know what you mean by "coil," but perhaps you are talking about the 24 volt terminals on the transformer. If you want to test the output, the proper way is to test between terminals (not to ground) You should have 24 volts or something close to it. Your meter may also be picking up "Phantom voltage" (voltage that is not really there) If you are really getting 120 volts on the output side, something is indeed wrong and you should shut it down and get a replacement transformer. If line voltage is applied to the electronic controls within the furnace, they may also have gotten damaged.