LP furnace makes noise

[FDchief]

My LP furnace works great, but for the last couple of years, after the furnace kicks off and the blower than stops, I get a clank like a metal door is closing. Any ideas on what this could be.

[DriVer]

Quote:

Originally Posted by FDchief My LP furnace works great, but for the last couple of years, after the furnace kicks off and the blower than stops, I get a clank like a metal door is closing. Any ideas on what this could be.

Chief, Mine does exactly the same thing and I'm not worried about it. Just so long as it keeps providing hot air - I'm good!

Don't forget to change your air filters often! I have 2 filters, one in the floor under the bed and the other in the floor of the closet in the back of the coach.

[FDchief]

Thanks Driver, I do change my air filters often, probably mote than I need to. Good to know we have the same optional heat off signal!

[KIX]

The sound you are hearing may just be the metal of the heater firebox contracting.

[hamguy]

Quote:

Originally Posted by FDchief My LP furnace works great, but for the last couple of years, after the furnace kicks off and the blower than stops, I get a clank like a metal door is closing. Any ideas on what this could be.

That sound is the sail switch flap in the path of the fan air flow. It is a safety feature. It is meant to flap open when the fan starts to allow gas to flow to the burner. Should it fail to open, it prevents gas going to the burner.

So, it IS a metal door closing for all practical purposes. It is a noise you want to hear.

[DancinCampers]

Actually, it is a metal door closing. It is hinged at the end (rear) of the floor duct (actually a rod pin that goes into a hole on the top side of the duct). Opens on air flow, closes (by gravity) when blower shuts off. There is another door at the other end of the ductwork that opens when Aux Coach heater blower turns on. These two doors keep the hot air in the duct, and then up the registers.

My guess is the door was not closing properly before, but now is, or a rubber bumper stop has goes bad.

[FDchief]

The air flow door thought makes sense. Now thinking about it, it probably helps keep unwanted outside air out of the coach. Just a guess. Thanks to all, I will try and just ignore it.