trane xe90 15 tr old

Joey Propane

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

Saturatedpsi

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.

Doc Holliday

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.

Seasonalsurvival

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.