Main burner will not light. Hearthstone Sterling 8531

kduff9

New Member
Oct 15, 2020
13
New Jersey
My pilot light flame looks normal, but when it calls for heat and tries to light the main burner, the only thing that happens is the pilot light goes out. Any ideas where to start?
Thanks, Clark
 

kduff9

New Member
Oct 15, 2020
13
New Jersey
Well, it's at 40%. I have another LP heater feed from the same tanks, plus a cook stove, both are working normally.
I tried to light it today and the main burner lit, but only for about 15 seconds. Then both the main burner and pilot light went out. I was not able to get the pilot light re-lit, although I only tried a few times. I feel like there is a restriction in the gas feed somewhere, is there a filter or screen in the valve I can access? I'd prefer not to dissemble the valve, as I have no way to verify it's not leaking. It's the last device connected to a 1/2" line, about 25 feet from the tanks.
 

kduff9

New Member
Oct 15, 2020
13
New Jersey
I did have a guy replace the probe that senses the pilot light (thermopile?) and gave it a good cleaning, about 2 years ago, but other than that, it been used for about 15 years.
 

DAKSY

Patriot Guard Rider Moderator
Staff member
Can you post a close-up pic of the gas valve?
There should be wiring going into a terminal block at one end...
 

DAKSY

Patriot Guard Rider Moderator
Staff member
Perfect. The first photo is all I need.
There are three terminals on that block: TP-TH; TP; & TH.
TP = ThermoPile; TH = THermostat.
With the pilot lit & the burner switch to OFF,
set your multimeter to Volts DC & touch the tester probes
to the screws at TP-TH & TP.
What reading do you get?
 

kduff9

New Member
Oct 15, 2020
13
New Jersey
When the burner lit, the reading was 2.9 slowly dropping over about 15 seconds, until 2.5, when the burner shut off. The pilot light also shut off.
What is that telling you?
Thanks, Clark
 

DAKSY

Patriot Guard Rider Moderator
Staff member
I think you mean .29, correct?
If the millivolts are not holding steady, that thermopile may be on it's way out.
I'm thinkin one will cost about $60 or maybe a little more.
Depends on whether you go to a hearth shop or not.
It would be where I'd start.
If that's NOT the issue, you'll have a spare...
True Value carries Universal Millivolt Generators, or at least they USED to...
Good luck, & I'll be here if you need me...
 

kduff9

New Member
Oct 15, 2020
13
New Jersey
I've installed the new Thermopile , but I'm getting almost the same results. The voltage is .59 with the pilot lit and the burner OFF. When I call for heat, the burner lights and the voltage starts dropping. This time it lasted about 30 seconds before everything shut off, around .24 volts. I repeated this process three times. The pilot flame is strong, wrapping part way around the thermopile.
I'm guessing .24 is below the operating voltage. Does this sound like the valve is pulling too much current?
Do you have a next step/idea, to get this stove up and running?
Thanks, Clark
 

DAKSY

Patriot Guard Rider Moderator
Staff member
You have a SIT (or NovaSIT) gas valve. It can be checked for resistance with an ohmmeter,
but the specified operable range of Ohms would have to be looked up.
If you can find the correct numbers & the test says the valve is good,
Then I think I'd replace the entire pilot assembly.
Just for grins, can you post the wiring schematic from the manual?
 

kduff9

New Member
Oct 15, 2020
13
New Jersey
I've looked, but I'm not able to locate the owners/service manual, so I don't have a wiring schematic to post. I've gone ahead and ordered a complete pilot assembly. If that doesn't correct the issue, the only thing left is the gas valve, correct? I really don't mind throwing parts at it, as it been in service for so long they are most likely close to end-of-life anyway.
Thanks.
 
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Millbilly

Member
Dec 13, 2015
177
02648
Is your stove a bvent or direct vent? Does the pilot assembly have a thermo couple as well or just the thermo pile? Make sure the thermo pile leads are snug but dont over tighten. If you have a thermo couple make sure that is snug.
 

kduff9

New Member
Oct 15, 2020
13
New Jersey
Thanks for the reply Furnace-To-Fireplace. I checked the vent and found a birds nest in the inlet... I cleaned it out and checked the stove. I saw the same result. The pilot and burner light, the flame looks normal and continues to look normal (I couldn't see any change), right up until it shuts off. It takes about 30 seconds, I hear a 'click' and the pilot and burner shut off.

The new pilot assembly arrived today. After I finished the install, the main burner lit, I thought it was fixed... but after a little over a minute, the burner and pilot shut off with a 'click'.
--------------------

After writing the above text, I went back out to the stove to run through the process again, with my meter attached, to post the voltage measurements. With the pilot ON and the burner OFF, it was reading .6. After the burner lit, it started slowly dropping, down to .29, where it leveled off. The burner continued to stay lit. I allowed to to run for over an hour.
Do you guys feel it's fixed? I'm not sure why the first run with the new pilot assembly failed and the second time was successful.
I'm going to let it cool and later tonight re-start it.

Thanks for all the help, Clark