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Heating, Air Conditioning, Fridge, HVAC/Bryant Plus 90 low heat; runs continuously

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The heat coming out of our vents from our 21-year-old (installed 1993) Bryant Plus 90 (398AAV048100, 3992A02538) is not as hot as it used to be. It runs continuously and now takes several hours to heat the house from 60F to 65F. (It's been cold lately -- today's high/low is 13F/-3F -- but it shouldn't take that long for heat.)

The furnace responds normally to call for heat. The burners light and the blower blows. I checked the "squirrel cage" when off and it spins freely, so I think the blower is ok.

The only service it has seen was last year when I had a sticking/stuck gas valve replaced. A few years before that we had finally installed an outdoor condenser for AC.

I admit to not changing the filter as often as I should but I did replace it today.

When I took the panels off this time I noticed rust stains and traces of water/moisture from the collector box down to the floor. Following advice online I checked the trap located on the blower box. Although there was a light coating of brown gunk in it that did not prevent water poured into the trap from exiting to the drain. There was no water trapped in either hose connecting to the trap, although a few drops did come out of the larger, clear hose. There was no water between the collector box and the pressure valve. The hoses and connectors seem fine. The leak seems to be coming from inside the top-right of the collector box.

Further online information states there was a recall but I haven't verified if my unit was included. It hints at a faulty secondary heat exchanger that leaks water. As I understand it this is what improves the efficiency from 80% to 90%, but I'm lucky if I'm seeing 5% right now.

I'm afraid that, as one guy put it, my furnace has just "rusted itself into a scrap heap". If the recall applies, should I go that route? If not, does it still make sense to repair the furnace? Or is the most economical solution to replace it?

Answer
Hi Eric, Repairing a 21 year old furnace doesn't make sense to me. The repairs you describe could cost as much as a new furnace.

Running with dirty filters can cause many problems. Low air flow will increase the heat exchanger temperature causing early failure. You probably have dirt build up on the blower and A-coil. This decreases air flow even more. From your descrption that is what I think is happening.

IMO you would be better off replacing it. With the cold weather we are having I wouldn't set the stat back more than two degrees.

I hope this helps. If you decide to replace and you need help choosing the right furnace let me know.

Heating, Air Conditioning, Fridge, HVAC

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Jim S.

Expertise

I can answer questions on gas or electric furnaces, ac units and heat pumps. I don't work on boilers,chillers,or home appliances.

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I have been in the HVAC trade for over 35 years. For the past 15 years I have owned my own business. I am semi-retired so I can answer questions in a timely manner.

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I attended trade school for 5 years on weekends and evenings. This was very hard to do, but well worth it!

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