Furnace Frustrations

Messages
3,649
Location
Chicagoland
I have an Armstrong Ultra V tech 80 something or another furnace, circa 2001 or 2006 can't remember off the top of my head. 2 years ago it was doing exactly the same thing you described. Draft inducer kicked on, flame comes on, no blower though causing it to overheat and shut off. Once it cycled enough it'd kick on and run with no issues for a few times then do it all over again. If I selected to just run it in fan mode it would go with no issues. Selecting fan, letting it run for a few minutes, then clicking it to heat also resulted in no issues. The relays on the board had started to stick open. Apparently if the blower was already running it had an easier time closing that particular relay. $95 for a new board that I put in myself (bought with help from an HVAC business owner/friend in another state) and it's not been an issue since *knock on wood*
 

dnewton3

Staff member
Messages
8,474
Location
Indianapolis, IN
Originally Posted by opus1
And I'm back. Between snow removal and dealing with the furnace guy I wasn't able to check back in. smile Someone mentioned the intake/exhaust piping. We had a problem many years ago with the pipes being too small so they're 3" until right before they hit the furnace and they transition to 2". When this first started I also checked the pipes and they were clear as far as I could see. Fortunately, the furnace failed when they were here this time, and acted exactly the same way it's acted whenever I described the situation to them. But they were able to check additional things now and it looks like we're getting new control boards. We'll see what happens after that.
Let us know if that fixed the problem.
 
Messages
7,980
Location
MI
Originally Posted by dnewton3
[quote=opus1] Let us know if that fixed the problem.
+1 I just replaced the control board on my 25 year old Bryant for $60. I diagnosed a bad circulation blower motor relay and could even see it arcing and misbehaving. The new board has different style relays.
 

opus1

Thread starter
Messages
3,104
Location
Chicago Area
And I'm back. Final answer is - control boards. When I was watching the furnace cycle, I'd hear a click which I figured was the relay for the blower activating, but the blower wouldn't always come on, and then that set the stage for the over-limit condition. I told that to the furnace guys, but until they saw that happen for themselves, they didn't seem to believe me. Could have saved several trips to the house if they listened to me... smirk2 But once they homed in on it, new boards were ordered and installed the next day, and so far so good.
 
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