HVAC Site - Professional HVAC Contractors Forum banner
1 - 5 of 5 Posts

·
Registered
Joined
·
4 Posts
Discussion Starter · #1 ·
the flame roll out fuseable link popped due to excessive heat when the blower comes on. Does this mean the heat exchanger might have a hole in it
 

·
Registered
Joined
·
26 Posts
I would be inclined to make that conclusion. "Breached" HX's result in the combustion chamber(s) pressurizing (or at least becoming less negative in pressure) when the blower starts. :sad:
 

·
Registered
Joined
·
33 Posts
the flame roll out fuseable link popped due to excessive heat when the blower comes on. Does this mean the heat exchanger might have a hole in it
No, not that I'm aware of. What I would suspect as is most likely the case is an air flow issue or lack thereof air flow, most likely a dirty evaporator coil and/or dirty air filter(s). It's like blowing into a small brown paper bag, the already hot air has no where to go when the coil is plugged or a filter is dirty so the furnace becomes hotter and hotter as it builds up until a high temperature limit switch disengages electrical continuity or as you stated, "pops".
Wiith a clean evap coil andfilter, it's like blowing into a small bag that has subsantial holes all throughout it so the air can flow.

Elementary analogy, I know, but you get the idea.

With a crack in the heat exchanger you'd have pressure switch issues so more than likely the furnace will not start, period. You need a CO test performed and/or the heat exchanger pulled and visually inspected to verify if it is cracked.
 

·
Mackwvr
Joined
·
1 Posts
He issue

hI have had the same issue with Trane check for breach in that cell. If you have a digital thermometer. Place near the roll out switch it should tell you when the blower cycles.
 
1 - 5 of 5 Posts
Top