HVAC issue

[mstng86]

I have started hearing something after the heater cuts off.

The heater runs fine and warms up the house, but about a second or two after it cuts off there is a loud bang. At first I thought something fell but realized it is the heater making the noise.

What the hell is it?

[junk racing]

Is it a furnace or air handler? If its a gas air handler it could be the heat exchanger cooling down and making the noise, without seeing it its just a guess.

[mstng86]

I don't know what the difference is. I know nothing about HVAC stuff. It is an all electric house.

[junk racing]

Ok, usually a house with gas has a furnace for the heating, unless its been retrofitted with a heat pump. If its all electric its called a air handler which has a set of heating elements inside it, whereas a furnace has burners. It could be a simple case of expanding or contracting of the metals, or it could be some other contributing factor.

[mstng86]

So do I just need to get up there and look and see what is happening when it cuts off?

What am I looking for?

[junk racing]

just make sure its hung still no straps or anything is broken, look for anything that may be making contact with the cabinet....I went too a similar call about two weeks ago that a previous well known company came and changed out a system well they apparently were in a hurry and used 1/4 " screws too hold the straps up, ended up pulling them straight out of the wood and the air handler fell. Needless to say shes suing. It is a possiblity something is in the blower assembly, something loose in the cabinet etc.

[mstng86]

what does the air handler look like?

[junk racing]

Its a rectagular shape, depending on model and size about 4-5 ft long, if its in an attic it usually will be hung longways, if its in a closet in of course will be standing up.

[junk racing]

also could be low on return air, causing the case too flex...

[Bigcountry]

Your filter? May sound crazy. We bought one of those cleanable filters, and the outside frame of it is plastic. It doesnt sit real tight in the return, so when the air kicks on it sucks it up, then when it turns off it drops back down. Just an idea, ours makes a loud banging sound when it drops.