Rheem Furnace stuck in on off cycle

[vgundi]

Hello furnace experts,

My Rheem furnace does not seem to light up fully. The pilot lamp comes on and then goes off. The furnace is stuck in this loop. When the pilot light goes off, I held a match stick to see if the gas is still coming. The pilot does not stay on with the match stick. This is the first time I'm trying to use the furnace this season and I'm not sure where the problem is. Another thing I have noticed last winter is when it is really cold it took the furnance more than 30 mins to start working.

Appreciate your input.

Thanks

[CBHVAC]

No one here can tell you whats wrong with it behind a monitor. It COULD be about 4 different things, or more, depending on the model of the Rheem you have, if its actually a Rheem, or a rebadged Consolodated...etc.. You had problems last year....so the question you need to answer is when was the last time you had it properly serviced?

[almoran]

Buy a rheem, get rheemed. you're welcome.

[bbrase]

[vgundi]

I'm not sure if it is high efficiency model. This was installed by the previous owner I guess. Not sure how old it is also. This does not have LEDs which indicate the status. It has an electronic ignition. When I turn it on (set the temp to 70 deg) the pilot lights up for about 2-4 seconds and then dies down for about 2-4 seconds. During this time I dont think the gas is released because I was holding a match stick. The on-off cycle continues for some time and eventually in about 30 mins or so the heater started to work. For now things seem to be ok. Any suggestions as to what to do next? I'm wondering if there is a part that is temperature sensitive and needs servicing or replacing.

Thanks

[bbrase]

There is a termo couple that sticks into the pilot light flame tip, about 1/4" in diameter and 1" long. It is connected to furnace gas control valve. It's purpose is to sence heat, ie lit pilot light. If no heat is detected to turn gas off, or not on. Replacing that may do the trick.

[Boots]