I have a fairly old gas A/C central air unit which was working fine until last night. When the A/C unit was switched on (I live in Southern Cal.) I noticed a burning smell (electrical) which I tracked down to the unit in our basement. I immediately switched the system OFF at the control panel but there was obvious arcing still taking place around the circuit board wiring so I immediately removed the power at the circuit breaker... which stopped the arcing/burning. I also switched off the gas input for safety reasons.

My question: would it be worthwhile replacing the circuit board and surrounding wiring or will I have to replace the entire unit. There have been no other issues with the system, either cooling or heating up until now but I obviously don't know what caused the problem in the first place! What are the costs likely to be for either course?

Gus

How old is fairly old? what kind of shape is rest of the furnace? Are you seeing any signs of rust in the burner area? The name-model-and serial numbers might help us to determine the age.with a circuit board I`d say its not as old as some out there still safely in operation

how old is fairly old?,what kinda shape is rest of the furnace? are you seeing any signs of rust in the burner area? the name-model-and serial numbers might help us to determine the age.with a circuit board I`d say its not as old as some out there still safely in opperation

I'll have to investigate the details a bit further. I was obviously asking in general terms but I will need to find out these details and post them. Thanks for your response.

Gus

I'll have to investigate the details a bit further. I was obviously asking in general terms but I will need to find out these details and post them. Thanks for your response.

Gus

I now have the details of the furnace but not the age but I'm sure the experts can deduce one from the other! It's a Rheem Criterion 2 furnace, Model 07NAMGR, Serial no. FD50307F400007438. The board has burned out but there are no other signs of mechanical trauma. I know I'll have to get someone to diagnose why this happened but can the board be replaced and the system diagnosed from there? Thanks for your help.

Gus

A good honest/knowledgable tech should be able to tell you if the furnace is worth the cost of a new board/repair before he does the work,, then its up to you