Crazy Banging Noise that Service Guy Cant Fix After 3 Visits

[dmfelder]

I have a problem that has persisted for several years. Each year, a service guy tries another solution. The heater bangs like crazy, and it's not the ductwork. We have cleaned it, replaced the mother board, checked the gas pressure, checked the voltages, cleaned the flame sensor, and replaced the gas valve, to no avail.

Here is a video I posted online. It's pretty dramatic. Any * *. com/Furnace_Banging_Noise.wmv

[Freon]

First, to those trying to get the URL, there's a space before the C in * that needs to be removed for URL to work.

The noise sure sounds like the gas valve. Now the flame sensor could be the problem or the control board or a loose wire. Check all the wiring to the gas valve and to and from the flame sensor. Make sure all wires connected to ground (furnace chassis) are secure. I would verify it's the gas valve causing the noise by calling for heat and placing your hand on the valve body. You should feel the vibration and you should also see changes in the burner flame although it's such a rapid open/close (If it's the gas valve) you may not detect anything.

[Silverjwj]

You say it's been cleaned. Did you see the tech or whoever cleaned it physically clean the * When I was interning I saw some half ass preventative maintenance being done. If your burners are not clean they won't light off properly causing delayed ignition.

[Mr Bill]

Sounds like it could be related to a drain, water or vent issue, seems to be a solenoid sound that I hear, also check for moisture in a vacuum hose.

[Mr Bill]

I am sure he is probably also talking about a 90+ condensate type furnace, this is why I felt it could be a vent issue or drain hose sagging holding water, or PVC exhaust pipe for a sag.