Vermont Casting DV360RN won't light.

[Caseykit]

I just moved into a house with this fireplace. It looks brand new and used very liitle. It was tested during inspection though and worked. The pilot light lights just fine but I can not get the fireplace to come on no matter what. There is a side switch like a light switch and I turned it on. Honestly I am unclear which way to point the pilot light turn control nob for one thing! Anyhow nothing lights the fire.

 

[DAKSY]

The "Pilot" knob needs to be in the "On" position.
There is a White line on the valve which indicates
the position for knob...On, Pilot or Off.
If you can't see it, post a pic & I'll point it out.

 

[Caseykit]

It is on. I’m sending pictures. Thank you for helping.

 

[DAKSY]

First of all, are you technically capable of following instructions?
Not trying to dis you, but I am a service tech & need for you to understand me.
If you don't have the confidence to follow my instructions, we won't get anywhere.
That being said I have a couple of questions...
When you flip the wall switch, do you hear a "Click" from the gas valve?
On the other side of the gas valve (left) there is a terminal block with the wires connected to "TH", "TP", & "TH-TP"
If you jump the terminals where TH & TH-TP are, using a wire or a paper clip, what happens?

 

[Ldsball]

First of all, are you technically capable of following instructions?
Not trying to dis you, but I am a service tech & need for you to understand me.
If you don't have the confidence to follow my instructions, we won't get anywhere.
That being said I have a couple of questions...
When you flip the wall switch, do you hear a "Click" from the gas valve?
On the other side of the gas valve (left) there is a terminal block with the wires connected to "TH", "TP", & "TH-TP"
If you jump the terminals where TH & TH-TP are, using a wire or a paper clip, what happens?

I have a DV360 RN and the pilot stays lit however when I light the fireplace it turns on for a couple of minutes and then shuts off. Any idea what that could be? I have replaced the 3 way pilot assembly and replaced the entire sit valve. Still having the same problem. Any suggestions?

 

[Millbilly]

I have a DV360 RN and the pilot stays lit however when I light the fireplace it turns on for a couple of minutes and then shuts off. Any idea what that could be? I have replaced the 3 way pilot assembly and replaced the entire sit valve. Still having the same problem. Any suggestions?

How do you turn on the fireplace? Remote, wall switch, tstat??

 

[Millbilly]

How do you turn on the fireplace? Remote, wall switch, tstat??

When it shuts off does the pilot shut off also?

 

[Ldsball]

When it shuts off does the pilot shut off also?

Wall switch. Yeah it does shut the pilot off as well.

 

[Millbilly]

Are you watching it as it shuts off? If so does the flame turn blue, anemic, and start to lift off the burner? The is called ghosting and us a symptom of a blocked vent.
Other cause make sure thermocouple is tight into the valve

 

[Pal_OOS]

Same problem, 36BDVT, SIT 820. The t-couple/pilot mVolt is good - 22.5mV, +the pilot flame looks good (hence good mV).
The thermopile mV also seems fine - 600+mV burner off, 150mv with burner on.
It looks like the pilot shuts off randomly, after 5min-20min - and takes the burner with it (no t-pile flame, so no mV).
24 years old, the pilot assembly (incl 2 thermo's) was replaced 5 years ago - so should be good.
I didn't test the safety magnet (requires valve removal) - any experience with this or other valve failure that might cause this?
DAKSY - sounds the same as your problem... any luck? You mentioned you changed the SIT 820 valve, didn't fix it...?

 

[Millbilly]

Does this have a blower? I recently had a customer who's burner and pilot would consistently drop moments after the blower would kick in. I eventually found a severely pinched power cord and I suspect the ground was shorted to hot. Fireplace will run fine without the blower on.

 

[DAKSY]

I prefer to see tcouple mV at 27+. The mV on the burner looks to be too low as well. Can you adjust the pilot up?

 

[Pal_OOS]

Thanks Millbilly - no blower.
DAKSY - I'll try adjusting the pilot up. The 22+mV t-pile is within the spec of 15-35 mV.
The 600mV off/150mV on t-pile is also in the SIT spec of 325mV/100mV, plus it seems the problem is with the pilot going out.
I'm leaning towards having the valve assembly replaced (24yrs), but it would be nice to have a root cause.
Thanks!...

 

[Fingerlakes Fireplace]

I prefer to see tcouple mV at 27+. The mV on the burner looks to be too low as well. Can you adjust the pilot up?

i agree with you on most things, however i have found it almost useless to test the voltage on the thermocouple. i have found many thermocouples and thermopiles that had good or even high voltage without a load, but as soon as you applied a load, the voltage would drop to zero.

Testing the voltage of the thermopile is mostly useless as well, UNLESS it is tested under load! (with it powering the valve) very easy to do with a thermopile, not practical with a thermocouple.
If you turn the gas valve pilot knob to "pilot", you can power the valve without having a flame on the main burner while testing.

 

[DAKSY]

Point taken, FF, but ya gotta start somewhere, with a TC. FWIW, I always test the TP under load.

 

[Pal_OOS]

DAKSY and Fingerlakes Fireplace - thanks for your input!

I adjusted the pilot up a half-turn (a visible increase, but not huge). Still extinguishes. 4 tests:
1. Pilot on for half hour (fine), then burner on Low (fine)... then both extinguish 90sec after the burner came on
2. ~the same start.... both extinguish 50sec after the burner came on
3. Pilot on for 5min, then burner on Low (fine)... then both extinguish 40sec after the burner came on
4. Pilot on for 5min, then burner on High (fine)... then both extinguish 40sec after the burner came on - vid attached (~3MB)

The pilot is stable on it's own, and for a period after the burner comes on... and then 'clunk', both shut off in an instant.
The time-to-extinguish after the burner is ignited started at 90sec, declined to 40sec.

Maybe a fault in the safety magnet or SIT valve? Or a fault in the thermocouple? (would the pilot go out so quickly?)
I'm happy to have 1 or both replaced, but preferably based on a best guess at the cause of failure..

Thanks for the expert input!... Paul
(more vids, if useful: https://drive.google.com/drive/folders/1O7ODxJdtSBpDpaFQgFXq4TpUNodlphtI?usp=sharing)

 

[Lennox65]

DAKSY and Fingerlakes Fireplace - thanks for your input!

I adjusted the pilot up a half-turn (a visible increase, but not huge). Still extinguishes. 4 tests:
1. Pilot on for half hour (fine), then burner on Low (fine)... then both extinguish 90sec after the burner came on
2. ~the same start.... both extinguish 50sec after the burner came on
3. Pilot on for 5min, then burner on Low (fine)... then both extinguish 40sec after the burner came on
4. Pilot on for 5min, then burner on High (fine)... then both extinguish 40sec after the burner came on - vid attached (~3MB)

The pilot is stable on it's own, and for a period after the burner comes on... and then 'clunk', both shut off in an instant.
The time-to-extinguish after the burner is ignited started at 90sec, declined to 40sec.

Maybe a fault in the safety magnet or SIT valve? Or a fault in the thermocouple? (would the pilot go out so quickly?)
I'm happy to have 1 or both replaced, but preferably based on a best guess at the cause of failure..

Thanks for the expert input!... Paul
(more vids, if useful: https://drive.google.com/drive/folders/1O7ODxJdtSBpDpaFQgFXq4TpUNodlphtI?usp=sharing)

Have you tried cleaning the pilot orifice? The pilot flame looks dirty and lazy, it is not engulfing the thermopile as it should.

If cleaning does not help, I would replace the entire pilot assy.

 

[Pal_OOS]

Lennox65 - thanks - yes I did clean the pilot, but I agree it looks 'lazy' + more orange than there should be.​

Based on inputs on poor pilot flame and possible thermocouple voltage issues, I'm going to go with replacing the entire pilot assembly.
To me, the consistent failure mode
- pilot stays on by itself
- pilot+burner go out together+instantly 1-5 minutes after the burner comes on
...suggests that the problem lies in the pilot/thermo's, not in the gas valve.

Thx much... Paul

 

[Fingerlakes Fireplace]

lazy pilot flame + excess air coming in by pilot flame.
open the pilot flame adjustment screw the whole way!
That is what the pilot orifice is for!
restricing the gas flow to the pilot via the adjusting screw makes for a lazy flame.

 

[Pal_OOS]

Yes, problem in the pilot assembly... likely lazy pilot flame, etc. as FF said. Turned up the pilot - still lazy.
Replaced pilot assembly - much cleaner pilot flame, all now works.
Thanks FF and L65!