Heat n Glo pilot will stay lit but fire won’t

[NoraNeedsHelp]

Hello!! We have a Heat n Glo log fireplace. It was probably installed around 2004. We moved in around 2007. We’ve used it on and off over the years without issue, but this year we can’t get it to work. We have cleaned out everything. We have replaced the thermopile and thermocouple. We even replaced the gas valve (7000mvrb‑6‑lc‑lp). We can get the pilot to light and stay on. But once we turn the knob to on and hit the on switch, the pilot goes down, and the main burner will eventually have small blue flames, then poof a few times, then we hear a click, and everything turns off including the pilot. We feel like we’ve tried everything. There is airflow from the outside vent. What are we missing?? Thanks for any advice you have!!

We have a video, but it’s too large to upload.

 

[wooduser]

. But once we turn the knob to on and hit the on switch, the pilot goes down, and the main burner will eventually have small blue flames, then poof a few times, then we hear a click, and everything turns off including the pilot.

When you push down on the gas valve to get gas to flow to the pilot light, you are pushing against a safety valve designed to shut off all the gas to the fireplace if the pilot goes out.

The small thermocouple shouldn be engulfed in the pilot flame and generates a small amount of electricity to energize a magnet that holds the safety valve open. If the pilot goes out, or doesn't have enough heat on it, the magnet fails and all the gas shuts off to the pilot light and mainburner both.

You can apparently get thje pilot to stay on, but when you turn on the main burner the pilot burner flame gets smaller and the main burner only has a small flame. The small pilot wont put out enough heat to keeo the magnet energized and thus the pilot safety shuts off all the gas.

That describes a condition where the gas pressure to the fireplace is inadequate. Enough to keep the pilot light lit, but when the main burner is turned on there is not enough gas pressure to have a good main burner flame and the piklot light, now with inadequate gas prwessure, is too small to keep the pilot safety powered up.

So -----do youn have propane or natural gas? What other gas appliances do you have, and do they seem to be operating normally? Check to be sure that the shutoff valve for the fireplace is turned fully on (counterclockwise until; it stops if it's a wall valve. Check to be sure that the electric gas valve control knob is turned to the on position.

How old is the fireplace?

 

[NoraNeedsHelp]

Thank you for your reply! That makes perfect sense. We use propane. The fireplace is the only appliance that the propane feeds. We just use a small (gas grill size) propane tank. You are right, when we hit the switch to turn it on, the pilot light goes down and the thermopile is no longer being touched by the flame. So there is enough pressure to turn the pilot light on, but not the fire. Do you know a way to increase the gas pressure?

The unit is 13 years old. But honestly over the past 11 years, we have barely used it because we’ve always had a kid under the age of 3. So hopefully it still has a lot of life left in it!

 

[wooduser]

. We just use a small (gas grill size) propane tank.

Your gas fireplace uses propane as a gas, not a liquid. But your propane tank mostly stores liquid propane.

So to get gas you can burn, your tank has to absorb enough heat from surrounding air to boil propane from a liquid into a gas. Just as it takes a lot of energy to boil water into steam, it takes a lot of heat to boil propane from a liquid into a gas,. And the heat to boil the propane has to be absorbed from the air surrounding the propane tank. That can be a problem with a small tank during the winter time and the relatively large demand for gas when you turn on the main burner.

What can happen is that the propane is cold, but can supply enough gas to operate the pilot light. When you turn on the main burner, the pressure can decline, causing the pilot light to get smaller and the main burner to be small because the gas pressure is low and inadequate. Then, the pilot shuts off the gas because it's not being kept hot.

So you may need a larger tank to operate the fireplace reliably.

If the fireplace starts working when the temperatures increase, that would support this theory. You could also put you tank of propane in a tub of warm water and see if the fireplace operates OK then ----that would tend to confirm the problem.

A bigger tank has greater surface area which can absorb heat from the surrounding air.

 

[zrock]

I would safely bet your tank regulator is faulty or dirty or u have a blocked line someware with a cobweb.. or your bbq tank valve is faulty or it's not tightening properly not releasing the tank safety. Working in a RC park and seeing some extreme cold temps I very much doubt your propane is freezing up. It's quite often the regulator or the connection to the tank

Sent from my SM-G950W using Tapatalk

 

[wooduser]

Dunking the propane tank partially in a bath of warm water to see if the fireplace then operates properly might be a practical way to identify if this is the cause of the problem. Waiting for warm weather to see if the problem goes away might also be a way to see if this might be the problem.

It's more likely to be the problem if you've been experiencing unusually cold weather recently.

But of course as Zrock suggests ----could be another problem such as he describes as well.

What I've done is to suggest a possible problem and some simple ways to test the theory. Your own experience with the fireplace might also tend to confirm this theory or not.

And it seems likely that we have identified a gas pressure problem as the likely cause of the problem, which is helpful. The task remaining is likely to be finding out just what is causing the inadequate gas pressure.

Certainly checking the gas connection at the tank to see if it was connected properly, and perhaps disconnecting and reconnecting it to see if that solves the problem might be a further thing to try. Tapping the regulator with the handle of a table knife might help jog something into working again ----but that's not to suggest pounding on the regulator ----just a few modest taps to possibly jog something back into working.

 

[NoraNeedsHelp]

Thank you! Thank you! Thank you!! You both have been so very helpful and probably saved us a lot of money! We disconnected the supply line from the tank to the house connection. We blew the line out to make sure there was no blockage. When we reconnected, it worked Thanks again!!

 

[wooduser]

Heh, heh! Another mystery solved! We just don't know exactly what it was that caused the improvement!

 

[zrock]

Glad u got it fixed... figured it was a connection or blockage issue.

Sent from my SM-G950W using Tapatalk

 

[wooduser]

Glad u got it fixed... figured it was a connection or blockage issue.

That does seem likely.