What's up with my heater?

My propane-fueled heater is making noise, like an ill-tuned woodwind being blown by an amateur. It’s a high-pitched squeal. It happens occasionally as it kicks on. So what’s up with that?

Clogged fuel lines? Does it happen if you run the gas, without a flame?

The furnace is fed by a 124 gallon tank. I’ve never checked the fuel line. (Wouldn’t know how.) It happens when it is very cold. Maybe there’s moisture in the propane that’s freezing? I’ve never run it without a flame.

Check the burner assembly - paying particular attention to the venturi/orifice area - for spiderwebs and other detritus. Spiders just love to nest in these things.

Does it sound like a Corrugaphone? They make those out of gas pipes.

No audio on that clip.

Ack! The newmusicbox site seems to have lost its sound.
There’s a sound clip of a corrugaphone on this page, titled ‘branching’.
When gas moves through a corrugated pipe, the corrugations impose a resonance on the flow. The right combination of flow rate and corrugation space will produce an audible whistling sound.

Does it have a fan or blower? If so, I’d vote for a dry bearing.

It does have a blower, but it doesn’t come on until the furnace warms up a bit. The sound happens when the furnace is igniting.

Can you run the fan without the burner? Even if you have to jump something temporarily, that will help to narrow things down.

I’ve been running the furnace recently. The howling has gotten worse. It lasts longer than it used to. The sequence is this: The thermostat clicks on. Gas flows into the burner. In a few seconds the howling starts. It continues for up to 20 seconds. Then it quiets down and a few minutes later the blower comes on.

When did you last clean the combustion chamber?
Tiny clinkers and bits of incinerated bugs build up over time and impede combustion.
My furnace quieted considerably after I cleared the dust bunny off the air intake for the burner manifold, and blew a few hundred grams of incinerati out of the burn box.

i don’t even know where the combustion chamber is. I should find out where the filter is, and replace it, now that you mention dust.

I would suggest you get it serviced, you life ,may depend on it.

OK. Apparently I have an Empire DV-25-SG, and I found an owner’s manual online.

7. On Propane gas, if a whistling noise (resonation) occurs. 
   a. See Page 13, "Primary air adjustment". 
   b. Reduce manifold pressure. 
   c. Size main burner orifice with a drill bit.  For DV-25 use #54 
       drill bit.  For DV-35 use #50 drill bit. 

Page 13 says:

I’ll try this Saturday.


If anyone’s interested, I did try the instructions. The resonance was reduced somewhat, but it’s still there – and very annoying. The furnace has never been serviced since it was installed in 2001 or 2002, so I reckon it’s about time. Someone will come out a week from Thursday. Should cost about $90 plus tax.