My furnace was making a clicking noise and wouldn't ignite the burner sometimes when it was trying. Had a repair guy look at it and they say there's corrosion in heat exchanger, the drain pipe is clogged up, they say can replace 3 wire pilot system but it will keep going bad and i will need a new furnace is this accurate or can i replace more of the parts and be ok, it's only 20 years old or so?
A corroded heat exchanger is not a crack. If the unit is over 20 years old it will have some corrosion. Most of the time this is not dangerous Out of many instances of truly cracked heat exchangers, over 100. I have only found one that produced any CO (not CO2) in a level that is universally deemed harmful even over massive amounts of time (9ppm). This was due to a crack not only in the heating system but also in the vent pipe, so naturally the place was high in CO. Most furnaces if properly maintained burn at or near complete combustion which drastically limits, if not excludes CO from it's byproducts. A complete combustion produces only water and carbon dioxide from a hydrocarbon which is what LP and Nat. Gas are. If the drain pipe is clogged it is a simple fix. Is he talking about the condensate drain for your AC? If so this is unrelated to your furnace problems unless the evaporator coal is limiting airflow and is in need of cleaning. A three wire pilot system is a cheap part that can be installed in under an hour by even the worst technicians. This guy is trying to sell you a new furnace, end of story. This is a very common practice with BS HVAC companies. Many have blanket policies that state that if a service tech comes into contact with an X year old piece of equipment, find a reason to replace it. Heat exchangers are almost always used for this scam. That said, if it is in your budget, it will be better for you in the long run to replace an old piece of equipment. The efficiencies are much higher now and you can even get back rebates from your utility company. If it's not in your budget, then run the thing into the ground. Either way, I'd call another company as the way you put it this one sounds shady.
Furnaces will last 25-30 years on average, although newer ones will save some energy. The statement about the pilot system is a tip off that you got a con man who is trying to sell you a new furnace. Get another opinion, and don't mention the first one at all. When they give you their opinion, then you can ask about the heat exchanger, if they didn't mention it.
20 years is about as long as a furnace lasts.If there's corrosion in heat exchanger a hole is not far behind and that can let CO2 into the house. The best thing is a new furnace is more fuel efficient and that saves $ in the long run. Of coarse nobody likes to plunk down all that money.
