Fallen Empire: DV-25-2SG, Growls, Turns Off, Pilot Goes Out

ktccapo

Morning,

I've got a propane-fired Empire direct vent wall heater in a commercial office space. It has a good pilot light (solid, blue flame extending 1/4" past the thermopile), a brand new thermoplie, pilot access door gasket, and fan sensor. The pilot tube orifice is clean.

I can light the pilot, and bump up the the t-stat to call for heat. The unit will light the burner, and produce a good blue flame for roughly 3-5 minutes. The unit then begins to make growling noises like it is starving for gas and/or air. Then both the flame and the pilot extinguish.

The manual says to clean/inspect the burner orifice. Would a dirty/plugged orifice be causing the symptoms I described above?

When I described these symptoms to the service tech over the phone, he said, "sounds like you need a new ($300) gas valve."

I welcome any thoughts and or suggestions. As always, the helpful advice on this forum is greatly appreciated. Thanks and best,

KT

Jamie Hall

How's the vent fan? That's the first thing I'd look at.

JUGHNE

I think this is a direct vent by gravity.
Is the fan we see in the pictures for warm air circulation?

Could it be that the fan is the growler, slows down and the unit then overheats and shuts down.
Although I believe these can run with gravity circulation of the heated air within the room...usually.

ktccapo

Hi, yes, this is a direct-vent-through-the-wall unit, fan is to circulate warm air through the room. Unit isn't even running long enough to get hot enough to turn on the fan...

EBEBRATT-Ed

A few possibilities.

Fan motor defective and your shutting down on high limit

Bad thermopile or gas valve. Yo would need to measure the out put from the thermopile to determine this.

Sticking regulator. Sometimes moisture gets in the reg and freezes up. It does not have to be cold outside, LP acts as a refrigerant

ktccapo

Many thanks for the replies. UPDATE: after having installed a brand new thermopile with no results, I went ahead and installed a new gas valve, and...nothing. It flames out now after lighting up even quicker than before. Burner fires, then spitting, sputtering, and dies, along with pilot...???

Tim McElwain

It sounds like you are getting cross contamination. Make sure the connection to the outside is secure and not leaking allowing products of combustion (CO2) to get back into the chamber. It sounds like that is what is happening. So you know I have worked on many of these over the years. You need to completely reseal the flue connection to outside.

ktccapo

Evening Tim, many thanks for your reply. Come to think of it, the unit is very loose on the inside wall, and it seems as though outside air is getting in around the collar that vents through the exterior wall. Should I re-tighten the unit to the inside wall and get some high temp silicone to try and seal up any gaps?

Tim McElwain

Yes I would take the outside hood off and clean the connection and then put some high temperature sealant and make sure it is connected back to the unit.

ktccapo

Morning Tim, and Happy New Year,

Just wanted to let you know that upon removing the heating unit from the wall, I discovered that that the 4" vent tube was actually all rotted out at the bottom, allowing for all sorts of external/in-wall air contamination. So many thanks for that tip!

That said, once I replaced the tube, the heater started up and ran just fine.

Now, it continues to start up and run, but is intermittently switching off, both pilot and burner, usually after a long run when the t-stat is satisfied.

As I mentioned previously, before you had suggested the possible venting problems, I had replaced the thermopile, fan switch, and entire gas valve.

I've read that the milivolts on the gas valve may need to be adjusted; if so, is this something that could be causing the problem described above, and how would go about properly checking/adjusting the milivolts with my amp meter?

Let me know, many thanks again and best,

KTC

Tim McElwain

Do you know how to check millivolts? Are you familiar with what you should be getting for readings? That being said after what you found with the "rotting" you may still have leakage and that can drive you crazy. It may be time for a new unit.

ktccapo

Thanks for the reply. I am fairly good with auto and general electric, have a multimeter and am willing to figure it out if it might make a difference...

On the unit itself, perhaps. It was installed in 2006, so roughly 14 years old. Do they generally last that long?

Thanks again and best,

KTC

mattmia2

They should last longer than that, but if the vent rotted out in that time clearly something is wrong.