Have you seen or experienced a melt down of the black plastic air in take or pvc air intake on 58mca furnace. The plastic has melted even in the burner box sight glasses.
Taken pictures but no sense in taking co readings just red taged the furnace. Had not seen a meltdown like this as the safeties failed. The heat melted the black box to the point that the pvc attached melted too. The co is always a good indicator of the secondary failure. We are seeing far to many. Now what? Do you rebuild or libable
they get red tagged immediately. Based on the circumstances, I will advise a replacement furnace. I'll always quote the repair costs for it and let the HO decide.
All the ones that had the plastic sight glass melt tripped the roll out switch, never had one where the safety failed to open and melted the PVC or air intake box....
clogged secondary!
only thing i can suggest is to make sure the furnace is pitched forward and you use a combustion analyzer to tune it!
My problem with all this is there are twenty plus furnaces in this location some horizontal some vertical. The drainage issue is well known but I have never seen a melt down usually the roll out protector would trip. The idea that the furnace needs to be pitch to guarantee secondary drainage not very acceptable. How do you deal with prior installations. The co test of the exhaust tells you that the exchanger is done.
What about the liability and how do you change the secondary on a horizontal furnace
that is 10 feet in the air.
you pull the furnace down, replace the guts, then re-install it.
Just finished replacing the furnace. We are talking to Carrier about adding a second roll out protector for the remaining furnaces. We will examine this furnace for secondary blockage. Will keep you advised.
Did u test the roll out switch? Being as unit installed horizontal, was the RO switch on the bottom side of burner box? They trip more often when on upper side of box, for obvious reasons.
As you have indicated; we know the rollout failed since the melt occured. The rollout is on top of the burner box in this horizontal installation. But until we examine the furnace on the ground we don't know if the wires melted together or if the thermal device just failed. Carrier is replacing the furnace with a new unit and will advise us further once we send back the unit.