[jcapaci]

I have a free-standing propane stove. Sometimes when I turn the thermostat up (when the stove is off) the pilot will go out.

At other times the burner simply wont light, although the pilot is still lit.

Or the burner wont light even though the ambient temperature is less than the thermostat setting. (and the pilot is still lit)

At other times it works fine.

With regard to problem number two, it has been suggested the wires from the stove are too small. The distance from stove to thermostat is approximately 25 feet. I'm guessing the wire is about 24 gauge.

Could the two problems be related? Or do I have two separate issues?

[Gene]

[QUOTE=jcapaci;56140]...The distance from stove to thermostat is approximately [B][U]25 feet[/U][/B]...[/QUOTE]

What kind of stove is it? Sounds like this is a heater? What is the complete model number?

Gene.

[jcapaci]

Hi Gene,
It is a heater-it is a Brass Flame model BF 40
The controller on the back has a label with the following info:
Robertshaw-Grayson
7000MVRB - 4 - LC
758-716-441 Max 1/2 PSI
Lo 1.3 - Hi 3.5
For Use With Millivolt System Only
9530 Assembled in Mexico

Thanks for your help,
John

[Gene]

John,

Unfortunately I'm not familiar with HVAC. Maybe somebody else on the forum can help you better.

Gene.

[Hearthman]

This sounds like a 700mv thermopile powered valve. You could have low inlet gas pressure, dirty pilot orifice, undersized gas piping, weak EPU in the valve or just a tired thermopile. Takes comprehensive troubleshooting. If you are not a pro, hire one. If you are a pro, you will need a set of gas pressures for inlet static pressure, inlet burning pressure with entire house under full load, manifold pressure, valve Ohms on EPU and main operator, WSK Ohms, millivolt readings btw contacts, open circuit mv on thermopile, closed circuit on main operator,

Your other problem is you say this is LP but the numbers you read off the valve are for NG. Has this valve been converted to LP? Usually 10.0 wci manifold LP.

Wall switch wiring should be at least 18gauge with good clean, firm contacts and a few joints as possible. Switch should be high quality low resistance type with gold plating on contacts.

HTH,
Hearthman

[jcapaci]

Thanks for the help. The reason I posted this problem is that I did hire a professional.

And the stove was supposedly converted to LP about five years back.

He changed the thermopile.
He changed the main valve.
He installed larger piping to the tank.
He cleaned the pilot orifice.

He probably did other things as well because he visited us about six times.

After each visit the way we would test the stove was to use it for a while to see if the most recent fix actually fixed it. Eventually the stove appeared to be working; I asked him what he did that made it work. He said he wasn't sure.

Worked fine for about a year, then began acting up again. Most recently it has taken to turning off while the main burner is on. Both the main burner and the pilot simply shut down after about fifteen minutes of operation. In addition to the other problems.

Almost sounds as though there is a short in the main operator-or maybe the thermopile is bad?

[icehouse]

From Honeywell Controls : Q335 Thermocouple is a quick dropout thermocouple used in
conjunction with the Q313 Thermopile Generator in the Q382
Pilot Burner. The flame in the pilot burner is directed toward
the thermocouple and the thermopile. As long as pilot flame is
present, the millivolt output from the thermocouple keeps the
safety valve in the gas control open, allowing the main gas to
flow to the appliance on demand. The millivolt output from the
thermopile energizes the operator in the valve on demand.

Q313 Thermopile Generator contains multiple thermocouples
connected in series to increase the millivoltage output. The
power generated is sufficient to operate an automatic millivolt
gas control system, independent of any outside power
source. Don't know if this helps.

[icehouse]

From Robertshaw :

[williamsce]

check thermo couple or gas pressure coming into the valve