Flame Strength/Expansion Question

Do you have a multimeter and know how to use it?

So I think your thought process is incorrect in that the pilot flame "grows". The gas flows to the pilot and burner from 2 separate lines from the valve. The burner line feeds the burner pan and the pilot simply lights it. When you turn on your burner I would make sure your valve for the burner is being energized first. If it is the next step is to check for burner flow obstruction.

Look at your valve and let us know if you see where an orange and a green wire connect to the valve. One energizes the pilot and the other the burner.

It looks like you have an "intermittent pilot" ignition system.

When the burner is turned off, the pilot burner and main burner shut off completely.

When you turn the thermostat or switch on for heat, the gas to the pilot burner is switched on along with a spark to light the pilot burner.

If the pilot lights, it engulfs the rod on the right. An AC voltage is applied to that electrode. When the pilot engulfs the electrode, a small DC current flows through the electrode, through the pilot burner flame (which rectifies the ac to dc) to ground. The fireplace electronics can detect that DC current, and when it finds it it turns on the main burner gas.

It sounds like the pilot is lighting but not the main burner.

Daksy is leading you through the process of determining why the main burner gas is not being turned on ----there are several things that can be the problem.

N8T said:

I have a Heatilator gas fireplace Model CD4236IR. I am unable to determine why flame does not expand or strengthen after ignition. See photos.
1) Entire pilot assembly was replaced a couple years ago and fireplace was in good working order.
2) Pilot ignites easily and blue flame is present but flame never expands or strengthens after lighting.
3) Today I inspected entire pilot assembly for dirt or corrosion and it was very clean. I lightly cleaned the rods just in case and vacuumed the area. I repeated ignition and flame remains the same as seen in photos.
Thoughts on further troubleshooting? Thanks!

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are your burners actually lighting?

Yes. DC low setting. One probe on connector if you can sneak it in there, other on the valve body. I can allready tell you will see voltage to the orange one. Test the green one to the main when you turn it on. You will likely see an initial voltage then a lower maintenance voltage. If you see this now on to the next step. You can try gently rapping on the valve as Daksy said and checking burner orifice/line for obstruction.

Yes. Use your fireplace! The worst thing to do is let them sit for years in my experience.

N8T said:

I placed the black probe on ground and red probe on connector with green wire still attached to connector. My reading was 1.48 when using the DCV 20 setting on my multimeter. Then I started gently wrapping on the valve with the plastic handle of screwdriver and that is when gas started to flow to the burner. It is now functioning. So based on my review of Daksy's comments it sounds like the problem was a stuck solenoid in the regulator head. Is there any proactive maintenance I should take going forward to prevent this from happening again? Also, when the solenoid was stuck what problem does that cause? In other words what is the function of the solenoid? As you can tell I am learning about how these work. Many thanks to all of you gentlemen for helping me. I really appreciate it and wish you all a happy holiday. Thanks again!

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N8T said:

. My reading was 1.48 when using the DCV 20 setting on my multimeter. Then I started gently wrapping on the valve with the plastic handle of screwdriver and that is when gas started to flow to the burner. It is now functioning. So based on my review of Daksy's comments it sounds like the problem was a stuck solenoid in the regulator head.

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Ummm. Frankly I've never been involved with repairs on this ignition system, which came out after I retired from doing fireplace repairs. So take the following comments with a degree of scepticism.

However, you have an ignition system that's designed to operate on a three volt battery power supply, and the voltage to turn on the main burner gas appears to be 1.48 volts. If you rap on the gas valve, that causes the main burner gas to turn on.

That suggests to me that the reason the gas valve isn't turning on reliably is not a sticking solenoid, by a voltage from the ignition module that is too low, not providing enough voltage to turn the gas valve on reliably.

]You might try measuring the voltage being supplied by the 3 volt power supply to see if it's at the proper voltage, or try putting fresh, high quality batteries in and seeing if thast improves things.

Another possibility is that the ignition control module is getting adequate voltage but poor electrical connections, such as a poor connection on a relay, is giving a substandard voltage to operate the electric gas valve.

The Dexen Industries ignition module GM-6KA information is available from one of your pictures. But if you would care to provide the make and model of the electric gas valve I'll see if I can find the voltage that should be applied to it to get the main burner gas to turn on properly. I'll bet that should be 3 volts and not 1.48 volts. You should find the make and model of the gas valve listed on the front of the gas valve.

I believe the voltage drops to maintain the valve open once it initially opens. If the flame looks fine I'd call it a day.

Millbilly said:

I believe the voltage drops to maintain the valve open once it initially opens. If the flame looks fine I'd call it a day.

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Do you have a reference for that suggestion on how the ignition module and gas valve work? On every intermittent pilot ignition system I've ever seen, the ignition module provides the operating voltage to the pilot burner and main burner gas and keeps it at that level until the burner is turned off. So on an ignition control powered by 24 VAC, the voltage to operate the gas valve is also 24 VAC. I am therefore presuming that with a 3VDC power supply, the voltage to operate the gas valve would be 3VDC, and a measured voltage of 1.48 VDC indicates a problem, such as that the main burner gas is not turning on reliably.

Furthermore, the ignition control has no way to detect if the main burner gas valve has opened. The ignition control turns on the pilot burner gas and detects the fact that the pilot burner has lit, and if and when it does, it turns on the main burner gas with the assumption that the main burner will light off the pilot burner.

But there is no independent check to verify that it has.

wooduser said:

Do you have a reference for that suggestion on how the ignition module and gas valve work? On every intermittent pilot ignition system I've ever seen, the ignition module provides the operating voltage to the pilot burner and main burner gas and keeps it at that level until the burner is turned off. So on an ignition control powered by 24 VAC, the voltage to operate the gas valve is also 24 VAC. I am therefore presuming that with a 3VDC power supply, the voltage to operate the gas valve would be 3VDC, and a measured voltage of 1.48 VDC indicates a problem, such as that the main burner gas is not turning on reliably.

Furthermore, the ignition control has no way to detect if the main burner gas valve has opened. The ignition control turns on the pilot burner gas and detects the fact that the pilot burner has lit, and if and when it does, it turns on the main burner gas with the assumption that the main burner will light off the pilot burner.

But there is no independent check to verify that it has.

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Sounds to me like his voltage is in spec. I believe his uses Dexen controls. I am more familiar with sit controls. Your presumption is incorrect.

Millbilly said:

Sounds to me like his voltage is in spec. I believe his uses Dexen controls. I am more familiar with sit controls. Your presumption is incorrect.

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Yes, you are correct. Thanks for the reference.

I learned something new today!

I suppose that's to conserve limited battery life. Do you know how that change in voltage works? Does it operate at the high voltage fo a few seconds, with the idea that the higher voltage will open the main burner gas valve, and then drop to the lower voltage on the assumption that the lower voltage will keep it open?

https://manuals.fire-parts.com/aws-...i_troubleshooting_guide_1-pdf.pdf?inline=true


It looks as though we are at page 12, "Does main burner light?

Answer, no.

Of course, this apparently is not a SIT valve....

wooduser said:

Yes, you are correct. Thanks for the reference.

I learned something new today!

I suppose that's to conserve limited battery life. Do you know how that change in voltage works? Does it operate at the high voltage fo a few seconds, with the idea that the higher voltage will open the main burner gas valve, and then drop to the lower voltage on the assumption that the lower voltage will keep it open?

Click to expand...

Glad I could teach something. I believe that is the concept.

N8T said:

Hi again. So I've been using my fireplace the last couple nights. Each time I must tap the valve with the plastic handle of my screw driver to get the gas to flow so that the burner will light. However, last night the burner flame gradually got lower and lower before it went out. So now I'm wondering whether the valve needs replacing or whether there is an electrical issue? The burner definitely does not want to light on its own or stay on over 30 minute period. My multimeter still reads 1.48 but I'm wondering if there is a problem with the black electric box module. Thoughts?

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https://downloads.hearthnhome.com/installManuals/4042_575.pdf


Here is a fireplace manual that apparently uses the same system you have ---I'd check your own manual to see that it's the same or similar.

Page 52-53 provide repair guidance if the fireplace doesn't light properly. Does the pilot burner continue to spark when the pilot is lit?

Unfortunately, the repair guidance doesn;t contain advice for you condition, which appears to be a pilot that lights but no main burner gas.

Since the pilot lights and the spark I'm supposing) does shut off, the next step should be that the module energizes the electric gas valve to reliably turn the main burner gas on. That's what I'm hearing is not happening.

That means either you aren't getting sufficient voltage to open the main burner gas valve (bad batteries or bad module) or the voltage is good but the gas valve is failing to open when it should (bad gas valve).


Please provide the make and model of the gas valve, which will be found listed on the front of the gas valve. I should be able to look up the specifications for the gas valve and see the voltage that is supposed to be provided to open the gas valve reliably.