Fireplace takes a long time to ignite

[diitto]

Hi, We own a Heatilator, Model NDV4236I, that was installed in a new home we had built in July, 2014. It has an Intermittent Pilot Ignition (IPI) starter with a simple on/off wall switch. If you run the fireplace frequently, say like every day or every few days, the fireplace starts within seconds after turning on the wall switch.

However, if you don't start the fireplace for say months, like during the summer months, when you do attempt to start it again, it takes well over a minute, sometimes over two minutes. You can hear the igniter clicking the entire time but it just doesn't start until quite a long time has passed.

Is this normal??? Can someone say why it might take so long to light after having been off for a significant amount of time???

thanks...

 

[Lake Girl]

Sounds like whatever natural gas was in the line feeding the fireplace may have dissipated during the long stretch of no use which would account for the longer ignition time. Have you contacted the company or their local rep?

 

[diitto]

Sounds like whatever natural gas was in the line feeding the fireplace may have dissipated during the long stretch of no use which would account for the longer ignition time. Have you contacted the company or their local rep?

Can you say more about your thoughts on the "natural gas" having "dissipated". and that such "would account for the longer ignition time"?? Dissipated how??? Through a leak??? Meaning perhaps that the line is what, full of air instead of gas??? Can you suggest how that might happen??? Clearly if I tried to start it today after having just run it yesterday, it will start within seconds. But if I wait a month, it will take minutes, maybe 2 minutes or so... Somehow it matters that is was just started recently.

I have tried contacting Heatilator once but they did not get back to me and as of yet, I haven't yet tried again. Thought I would do a bit of research on my own to try to find a possible explanation.

thoughts??? thanks...

 

[DAKSY]

You have a large gas line coming from the gas meter that may or may not be teed off to feed other appliances.
If you are using Natural Gas (NG), the pressure coming thru your gas line is about 1/2 psi. That isn't a whole lot of pressure.
The normal pipe diameter feeding the fireplace is 1/2" Inside Diameter (ID). The gas will go as far as the valve in your fireplace
in that 1/2" ID & be stopped there by the gas valve, if it isn't called for by the thermostat or wall switch.
On the fireplace side of the of the gas valve, there is a gas tube that feeds the pilot. The pilot lights first, then the burner.
That pilot feed tube is 1/16" ID & is open on the pilot end. That is where the gas will dissipate, once the pressure is shut off for a while.
NG is lighter than air so it just exits out through the venting & poses no danger.
When your switch or thermostat call for heat, the gas flows through the vavle & into the pilot tube. If there is a small amount of gas
remaining in the tube, the pilot will light in a short time. If there is NO gas in the pilot tube, just air, then the air has to be evacuated
before the gas reaches the ignitor spark in the pilot assembly. Because the pilot tube ID is very small, it will take awhile for the gas to
push the air out. Your situation is completely normal.
I hope this makes some sense to you.

 

[diitto]

You have a large gas line coming from the gas meter that may or may not be teed off to feed other appliances.
If you are using Natural Gas (NG), the pressure coming thru your gas line is about 1/2 psi. That isn't a whole lot of pressure.
The normal pipe diameter feeding the fireplace is 1/2" Inside Diameter (ID). The gas will go as far as the valve in your fireplace
in that 1/2" ID & be stopped there by the gas valve, if it isn't called for by the thermostat or wall switch.
On the fireplace side of the of the gas valve, there is a gas tube that feeds the pilot. The pilot lights first, then the burner.
That pilot feed tube is 1/16" ID & is open on the pilot end. That is where the gas will dissipate, once the pressure is shut off for a while.
NG is lighter than air so it just exits out through the venting & poses no danger.
When your switch or thermostat call for heat, the gas flows through the vavle & into the pilot tube. If there is a small amount of gas
remaining in the tube, the pilot will light in a short time. If there is NO gas in the pilot tube, just air, then the air has to be evacuated
before the gas reaches the ignitor spark in the pilot assembly. Because the pilot tube ID is very small, it will take awhile for the gas to
push the air out. Your situation is completely normal.
I hope this makes some sense to you.

Yes, that does make sense. At least most of it and the rest of it is likely just my lack of knowledge about the dynamics of how igniting gas works. Thanks... I was thinking it was very possibly OK as is and that just what you say above is what was going on but I am not knowledgeable about things like gas pressure, etc. So I needed someone like yourself to put some common sense numbers on top of what I was seeing. I've looked at the layout under the Heatilator before (have to remove the front, decorative cover screen to expose the bottom area under the Heatilator) and like you say I see what appears to be a 1/2 inch line with the main shutoff valve (set to open or on) heading into the gas valve and then I see a smaller, bendable steel line that comes out of the gas valve and heads toward the pilot area up above where the fireplace log assembly sits. I would take your word for it that the ID of that smaller line would be 1/16 ". I would just guess that that smaller line is maybe two feet long??? The gas line in our house feeds this fireplace as well as the gas furnace (up in the attic) and a hot water heater out in the garage. The gas meter is outside near that garage and so the gas line gets to the hot water heater first, then gets up into the attic to feed the furnace then it gets to the fireplace which is as far away from the gas meter as it could get (opposite corners of our house). So it's a long source line for sure.

The one question I still have is when you shut off the wall switch that tells the gas valve to close is that the fireplace flame shuts off rather hard but not till a few seconds later, meaning it first dies way down to next to nothing and that happens the moment you turn off the wall switch but then, a few seconds later, whatever flame is remaining shuts off with a fairly crisp sound where the flame suddenly disappears everywhere. As if THAT was the moment the gas supply was shut off. But I'm guessing you would instead tell me that no, the gas supply was shut off the moment you shut off the wall switch and saw the flame die way down but that there is still enough gas pressure, for a few more seconds, to sustain a smaller area of flame until it reaches some critical low pressure where there is not enough gas to sustain the flame, thus the reason for the crisp shutoff of all flame a few seconds after shutting off the wall switch. But it sounds like what you're saying is that is NOT a time when there is zero gas in the short, small output line from the gas valve but instead just an amount of gas not sufficient to any longer keep the system lit??? And that if you start it again say the next day, some gas is still sitting there, enough that a boost of real, new gas from the gas valve is sufficient to start the pilot quickly, versus if you let it sit for say a month when all the residual gas that was in that short line has had time to slowly drift away and at only 1/2 PSI of gas pressure, it takes time to push out the air that has filled that 1/16 inch line... Am I more or less correct there, especially regarding what causes the flame to extinguish crisply a few seconds after the flame dies way down immediately after turning off the wall switch???

Just that one more curious question. But even without an answer to that, yes, what you say does make sense and makes me feel better about what is going on and that what I am seeing is normal operation... thanks much...

 

[DAKSY]

When the switch is turned off, it stops the gas flow THROUGH the valve, but
there will still be gas in the burner that has to completely burn before the flames
extinguish. Again, this is a completely normal occurrence with gas units.

 

[diitto]

I appreciate the help... What you say makes sense... Thank you much...