# Vermont Castings RNV40 LP.  Pilot goes out when after turning knob to "ON"



## rhysjames (Mar 3, 2022)

Hey all,

New here to the forum, I tried searching if this issue has been discussed already but I don't see anything.

I have a Vermont Castings RNV40. propane stove which I just installed. I got this second hand but the previous owner said it worked fine with no issues and even had a recent video of it running.   I had the propane company install the gas line and hook it up, but when he tried lighting it, he couldn't get the pilot to light.  I removed the glass door and managed to light the pilot manually with a lighter, but it was a tall flame that was not even touching the thermopile and thermocouple.  I replaced the pilot assembly this morning and got a nice 3 way flame and managed to get the pilot to stay lit.  As soon as I turn the knob to "ON" I hear a click near the control valve and the flame goes off.   I made sure all connections were correct and tight. I called the local dealer and they said the control valve needs to be replaced. The problem is that the Honeywell VS8420E2012 control valve (VC Part #20000572) is obsolete and they show no available SIT valve conversions applicable.  Am I sitting on an expensive piece of cast iron or is there another issue that I'm missing?   Has anyone else come across this?

Thanks in advance


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## DAKSY (Mar 5, 2022)

The last time I encountered this issue with a VC B-Vent unit, the problem was in the wiring leading to & from the hi-temp safety thermodisk. Those wires are in a pretty harsh environment & the sheathing was compromised. Once I replaced them with new 18 gauge wire, the problem was solved. If the wiring is good , it could be the thermodisk. It’s located near the top of the stove & under the removable top.


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## rhysjames (Mar 5, 2022)

DAKSY said:


> The last time I encountered this issue with a VC B-Vent unit, the problem was in the wiring leading to & from the hi-temp safety thermodisk. Those wires are in a pretty harsh environment & the sheathing was compromised. Once I replaced them with new 18 gauge wire, the problem was solved. If the wiring is good , it could be the thermodisk. It’s located near the top of the stove & under the removable top.


Thanks for the reply.  Is the thermosdisk also the vent safety switch that has the two leads going to it?   It may also be called the spill switch sensor, not really sure what it does though.


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## edleno (Mar 18, 2022)

I just posted a nearly identical post on this forum.  From what I can see the high heat sensor at the top of the firebox goes on the pilot thermocouple and will shut off the pilot if it fails.  From my research the "pilot turns off when main turned on" is a known failure of the VS8420 valves.  I posted a question to see if someone with more experience could confirm.  I found this link https://www.woodstoves-fireplaces.c...QE-plWJ74VRe4mSZuRP8ROhsQmma-sWkaAgIoEALw_wcB for a replacement.


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## Fingerlakes Fireplace (Mar 19, 2022)

rhysjames said:


> Hey all,
> 
> New here to the forum, I tried searching if this issue has been discussed already but I don't see anything.
> 
> ...


Does the stove have a spill switch?
A Sit valve will work,  but it is not a direct drop in.


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## rhysjames (Apr 13, 2022)

It does have a spill switch. I disconnected the wire to the spill switch and tried to light the pilot which wouldn’t stay lit. (It’s a brand new pilot assembly).  Once I reconnected the spill switch I was able to get the pilot to remain lit. 

Could the spill switch still be defective ?


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## DAKSY (Apr 13, 2022)

Could be that you had a bad connection at the snap disk. When you unplugged it & then plugged it back in, you may have cleaned the contacts.


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## rhysjames (Apr 13, 2022)

DAKSY said:


> Could be that you had a bad connection at the snap disk. When you unplugged it & then plugged it back in, you may have cleaned the contacts.


the pilot staying on wasn’t the issue, I only unplugged the thermodisk to see if it would help the issue with the pilot shutting off after turning the valve to on.  The pilot stays lit but once I turn the valve to on, I hear a click noise and everything goes out. I’m really hoping it’s not the valve because these Honeywell valves are obsolete


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## DAKSY (Apr 13, 2022)

Have you checked wiring to & from the disk?


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## rhysjames (Apr 13, 2022)

DAKSY said:


> Have you checked wiring to & from the disk?


I bought some 18ga wiring and female connectors that I’m gonna wire up tomorrow and test out . I’ll keep y’all posted


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## rhysjames (May 5, 2022)

rhysjames said:


> I bought some 18ga wiring and female connectors that I’m gonna wire up tomorrow and test out . I’ll keep y’all posted


It didn’t change anything. I’m thinking if replacing the thermodisk (spill switch) would do anything. If not, I’ll have to suck it up and look into the sit valve option


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## Tech Guru (May 6, 2022)

Yeah, those old Honeywell valves would have a lot of issues like this.  I always gave my tips for this system as such:


Disconnect switch and thermopile wires from the operator head.  Bypass (jump out) the spill switch if there is a concern that part is defective.
Turn knob to pilot position, depress knob and light pilot
After an appropriate time holding in the knob, slowly release the knob (still in the pilot position), if it holds: great.  If not try again (after waiting a few minutes) and move more slowly, hold it pressed in longer, etc...
Then, when making that final 1/8 of a turn to go from PILOT to ON use 'safe cracker hands' - move that sucker as slowly and gently as you can
If the pilot has held after all that, add the t'pile and then switch wires back into the mix and test. (reconnect spill switch if applicable)
But if it still drops out at this point, you 100% need to replace the valve (SIT 820 option is best, but it is really tough to do on that RNV40 model, a 30 second Drop Out Robertshaw valve is a better match, fit wise)


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## Aja888 (Nov 19, 2022)

rhysjames said:


> It didn’t change anything. I’m thinking if replacing the thermodisk (spill switch) would do anything. If not, I’ll have to suck it up and look into the sit valve option


Hi rhysjames, were you able to get it going with a new thermodisk or did you have to foot the bill for a new sit valve? I have the same problem with mine(natural gas).


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## rhysjames (Nov 23, 2022)

Aja888 said:


> Hi rhysjames, were you able to get it going with a new thermodisk or did you have to foot the bill for a new sit valve? I have the same problem with mine(natural gas).


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## rhysjames (Nov 23, 2022)

I just replaced the old honeywell to the SIT Valve last month and it fired right up. I would just go for it, the honeywell valve is most likely shot.  I just need to figure out a way to secure the valve permanently and retrofit it so it it mounts underneath properly. I wont be back up to the cabin for a couple of weeks but I should be able to figure it out by that time.  I'm open to suggestions if anyone here has done it!


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## rhysjames (Dec 20, 2022)

Update - fireplace is working now with the new sit valve.  Now I want to figure out how to connect the T-stat switch to a nest thermostat.  Here’s some photos of the unit working


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