DV360 - Pilot Light shuts off when gas valve turned on

[Lexus1]

The Pliot light lights with no problems yet when turning on gas valve to ON, the pilot light goes out. I've replaced the thermocouple & thermopile and the problem remains. Any suggestions?

With the glass cover off, I do feel the vented area open because I feel the cold air from outside.

 

[DAKSY]

Who is the manufacturer?

 

[Lexus1]

Who is the manufacturer?

Majestic Vermont Castings

 

[Lexus1]

Majestic Vermont Castings

Any tips yet??

 

[DAKSY]

I would check all wiring to see if the sheathing has become brittle & the copper core has been exposed,
leading to a short in the system.
Not sure how old your unit is, but after a number of years of heating & cooling, the sheathing wears out.

 

[Tech Guru]

I would verify the valve type - It would either be the SIT 820 or the Honeywell VS8420. This behaviour is consistent with what I have seen/heard when the Honeywell valves begin to fail. Some tips regarding the Honeywell Millivolt valve: Always ensure the switch is in the off position when lighting the pilot. If the pilot holds when the knob is in the pilot position, let it sit for a while (several minutes) before making that final turn. And when that last turn is made to go from PILOT to ON, do so as gingerly and slowly as possible (I call it "safe-cracker hands"). These tips can help, but this scenario often ends up with the valve being the problem. If so, there are valve retrofit kits available, to replace the discontinued Honeywell valve with the more common (and more reliable, IMO) SIT valve.

 

[Lexus1]

I would verify the valve type - It would either be the SIT 820 or the Honeywell VS8420. This behaviour is consistent with what I have seen/heard when the Honeywell valves begin to fail. Some tips regarding the Honeywell Millivolt valve: Always ensure the switch is in the off position when lighting the pilot. If the pilot holds when the knob is in the pilot position, let it sit for a while (several minutes) before making that final turn. And when that last turn is made to go from PILOT to ON, do so as gingerly and slowly as possible (I call it "safe-cracker hands"). These tips can help, but this scenario often ends up with the valve being the problem. If so, there are valve retrofit kits available, to replace the discontinued Honeywell valve with the more common (and more reliable, IMO) SIT valve.

I have visually checked the wiring, no abnormalities found. I checked the part number of gas valve installed and it is a Honeywell VS8420E. Shall I order the same part number or is there a part number that supersedes this one?

 

[Tech Guru]

As Honeywell no longer manufacture that valve, the best method would be to retrofit the SIT 820 into place. I would have to defer to the Majestic/Vermont Castings technical support (or an authorized dealer) to verify the parts that would be needed. If this was a DIY project, though not typically recommended for items in the gas train (i.e. valves/pilots etc), www.ibuyfireplaceparts.com tends to be an online parts retailer that tries to have this info ready to go, just have your model and serial information handy.

 

[Piddler]

I would verify the valve type - It would either be the SIT 820 or the Honeywell VS8420. This behaviour is consistent with what I have seen/heard when the Honeywell valves begin to fail. Some tips regarding the Honeywell Millivolt valve: Always ensure the switch is in the off position when lighting the pilot. If the pilot holds when the knob is in the pilot position, let it sit for a while (several minutes) before making that final turn. And when that last turn is made to go from PILOT to ON, do so as gingerly and slowly as possible (I call it "safe-cracker hands"). These tips can help, but this scenario often ends up with the valve being the problem. If so, there are valve retrofit kits available, to replace the discontinued Honeywell valve with the more common (and more reliable, IMO) SIT valve.

This solution was suggested almost 5 years ago, but I found it and tried it today (Christmas Eve 2022) - was exactly the right thing (especially the "safe cracker hands")to get fireplace working today! Thank you!