Gas stove wont light

[JimK24]

I have a Vermont Casting gas stove with a Honeywell VS8420 valve on it. The pilot lights fine. When I turn the knob from "Pilot" to "On", I hear a clunk and the pilot goes out.

I'm getting about 27 mV at the tip of the thermocouple. I'm getting about 700+ mV at the Thermopile (between TP and TPTH). My coil resistance between TP and TH is 3.5 Ohms. I cleaned everything up but haven't been able to fix the problem.

At first I thought maybe I had a bad thermocouple or thermopile, but my mV readings are good.

Any ideas?

 

[DAKSY]

Chesk to see if there's a spill switch located near the top of the stove.
If there is one, it may have failed or the sheathing on the wiring to it
may have deteriorated, exposing the copper core & causing a short.
HTH.

 

[Wood Heat Stoves]

http://woodheatstoves.com/-p-12685.html

i just uploaded the book for you, see page 7 of the free pdf.....for the rest of the tests



is the unit b-vent? if so it might have a spill switch as mentioned above,

 

[JimK24]

Thanks for the info. I jumpered out the spill switch. Same results, pilot goes out when turning knob on.

Another interesting note - when I jump TH to TPTH (with the pilot lit and the knob in the pilot position) I can hear the typical valve click, just like when it used to light. When I jumper it it clicks, when I take the jumper off it clicks again - but the burner doesn't light.

Any ideas?

 

[Wood Heat Stoves]

what were the results of the other valve tests listed in the pdf i posted??

 

[JimK24]

Test A (coil resistance): 3.2 - 3.3 ohms
Test B (thermopile): 530 mV
Test C (thermocouple): 27 mV
Test D (operator pull in): couldn't test because operator would not pull in
Test E (resistance system): did not test. I didn't think this was relevant because I can not even turn the knob to "On" without the pilot going out.

Thanks.

 

[Wood Heat Stoves]

sounds like its time to call a vc/monesson dealer for a new valve...
i'd call the factory first to confirm, but sounds like a bad valve

i dont have much experience with honeywell valves