My furnace is 8 years old and was pit in by the previous owners. Last year it seemed to work fine. It's part of a central system and AC worked fine all summer. When i turned on the furnace this year it would heat about 2 degrees (so if it was 60 on the house and I wanted it at 66, at about 62) and then the furnace burner and fan shut off. The thermostat blinks HEAT and FAN, which it does when these were on. After some time, it would come on again. Eventually it will heat to the set temp.
I had a tech here to service and clean it. I also cleaned the air intake vent. He thought it needed more air (there is only one intake vent) because of the high pressure (this was before i cleaned it... it was a mess). Again, last year we did not have this issue. So it was suggested we need a new intake vent. He also thought the furnace was hitting the hi too quickly and that piece may be worn out. The other thought was to clean the coils, although the pressure on either side was fine.
So I'm wondering if the system worked 7 years, why would it need more air now? What else should I check or think about? Could it just be the limit switch that is tired? Any other reason this would happen?
Thanks for any help.
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was that changed?
the tech should be able to determine if it's cycleing off on high limit. if not i would suspect the flame proving device.
the tech should be able to determine if it's cycleing off on high limit. if not i would suspect the flame proving device.
The filter was changed when the tech looked at it (it was changed recently before that also). It is cycling off on high-limit, but his only thought was that it wasn't getting enough air (I've since cleaned out all the intake vents). Since it's running worse now, I'm wondering if some mech equip inside is failing, or if it's a gas issue? The gas lines on the property were replaced recently because they were leaking.
