Repairing the insulating layer inside the furnace

ArthurPeabody

I replaced the blower's capacitor in the furnace and it works as well as new. I'm seeing tiny bits of aluminum foil on the floor underneath a vent (they're in the ceiling). The access panel of the furnace had a layer of insulation with aluminum foil on it. This could be it. I didn't touch the foil; it wasn't exposed but a few minutes. What's the best way to repair it? Aluminum foil and contact cement? Is the foil even necessary? Could I just coat it with contact cement, or something else, to keep the insulation from eroding? Could I have done something to damage it?

delcrossv

Get some foil faced insulation board (glass filled) and replace the whole sheet. You don't want adhesive on the hot side of the insulation.

EBEBRATT-Ed

@delcrossv I think he's talking about the blower compartment when he changed the capacitor,

@ArthurPeabody

If you need to replace some insulation you rip the old stuff off and buy fibreglass foil faced duct insulation and spray it in place with contact adhesive.

If you just have a few places to patch the HVAC supply house's sell foil tape to repair the insulation. The big box stores may also have it....not sure or you can order a roll on line

ArthurPeabody

Yes, it's the blower compartment, not the plenum, so it's not as hot.
Can I use any contact adhesive? I have a spray can of Loctite® 'High Performance' 200. I've never used it for high temperatures.
I have a roll of foil tape. It's excellent stuff. I considered using just it as a whole layer.
Why did it start flaking off now, after 15 years? The blower seems to be blowing more strongly; the old capacitor may have decayed slowly.

delcrossv

If it's in the blower box, it shouldn't be that hot. Contact adhesive should be fine there.

ArthurPeabody

Thanks. I did it today.