# Heatilator NDV4236I-B Natural Gas Fireplace - Pilot Flame is Solid (no continue sparking) but Main Burner will NOT Light



## Kapinossa (Jan 26, 2022)

I know this subject has been discussed numerous times and I have sent several hours reviewed posts and suggestions. I originally posted a help request on this issue on a very similar posting that had already been resolved but I thought this needed a new thread since I have exhausted previous corrective actions. I hope that no one is offended by me starting another thread and if you have any inputs please use this thread for replies since I have included some additional details.

Also, the forum moderator can take whatever actions you feel are appropriate and I will adapt. A removal of my previous post is warranted.

Now to the issue:
I have the natural gas fireplace Heatilator NDV4236I-B unit with the IntelliFire Ignition System (IPI) and it was installed in 2017. Currently, the unit has only about 2 hours of total use in 2017.  It then sat idle until fall of 2020, and upon second ever use the main burner would NOT light even though everything else looked normal.  Specifically, the pilot ignitor sparked, then the pilot flame came ON and stayed ON without sparking, but then the main burner would NOT light.  After some health issues, I finally tried to use this fireplace this week but the same NO burner light was obtained.  After several days reviewing any information I could fine, I finally got around to testing the unit this month and is detailed below.

Testing accomplished:
1. All wiring and connections examined. Grounding screws checked and grounding wires verified that they were grounded.
2. 3 Volt transformer  verified that it is suppling 3 volts to the control module.
3. The 2 D cell battery pack supplies over 3 volts to control module with new batteries installed and transformer unplugged. (Battery backup power source did not change any outcome compared to use of 3 volt transformer.
4. Pilot solenoid has an ohm reading of 35 ohms. Not opened circuit.
5. Main burner solenoid has an ohm reading of 66 ohms. Not opened circuit.
6. With the wall switch closed, the pilot ignitor began sparking, followed quickly with pilot flame lighting and staying lit as long as the wall switch was closed. However, the main gas burner did NOT light.
7. At the green spade terminal of the gas valve, I measured 1.62 volts and holding while the pilot flame stayed lit but NO burner light off. This voltage was measure off the green spade of the Dexen gas valve after I the slide the green wire connector from the control module slight off of the spade so I could read the spade with the green wire connected to the gas valve from the control module.
8. Fireplace glass front was then removed to conduct startup test (open fireplace condition) and there seemed to be no excessive natural gas odor other than the pilot flame continue to stay lit as what was commanded.
9. With wall switch ON and pilot light stable, I have tried taping "Regulator Rap") the gas valve kind of aggressively, but still NO main burner lighting. I am NOT convinced completely that the valve is not stuck but my tapping did not result in any change and thus NO burner light. I tried this at least five times with a couple of different striking tools and stopped when I thought it was excessive striking. Maybe, I am not hitting the right place but I have used this technique on my old Heat and Glo units with a sticky gas valve to start the season in my previous home. It did require more striking energy after several years of cycles to begin the season.

I have NOT verified that the burner nozzle is unclogged or possibly the burner area is clogged up. I was hoping that someone could provide some insight on how to get under the log floor in this fireplace to lift / remove the main burner exit plate for access to the main burner nozzle area (not accessible from the bottom access area which has all of the controls). Any help would be appreciated to eliminate a clogged nozzle, as a possible problem with a unit used infrequently. I have attached a part breakout diagram from the Owners Manual. I think I need to get to item #16 Valve assembly but disassembly looks confusing and any insight would be appreciated.

Specifically, I am confused on how much hardware to remove to gain access to this burner area. I have allot of trouble shooting experience with Heat & Glo units but this burner configuration / valve assembly #16 looks very confusing in the owner manual part breakout. 

Also, If someone has a good idea on HOW to safely test if the main gas valve is opening or not after establishing a stable pilot flame, it would be much appreciated.


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## Lennox65 (Jan 27, 2022)

Kapinossa said:


> I know this subject has been discussed numerous times and I have sent several hours reviewed posts and suggestions. I originally posted a help request on this issue on a very similar posting that had already been resolved but I thought this needed a new thread since I have exhausted previous corrective actions. I hope that no one is offended by me starting another thread and if you have any inputs please use this thread for replies since I have included some additional details.
> 
> Also, the forum moderator can take whatever actions you feel are appropriate and I will adapt. A removal of my previous post is warranted.
> 
> ...


The valve may be stuck and the normal voltage at the green spade may not be enough to open it.
You can try "shocking" it open by using the back up battery pack with batteries in it. Remove the green wire from the spade.  Disconnect the leads from the battery pack. While the wall switch is on , and the pilot is lit, put one of the leads from the battery pack on the green spade and the other lead on the metal face of the valve body. (for ground) I usually use a battery pack that holds 4 AAA batteries so 6 volts are delivered. If 1.62 is the normal voltage, 3 volts from your battery pack may be enough.


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## Kapinossa (Jan 27, 2022)

Before I try to check for a clogged nozzle with a disassembly of the fireplace floor, I will try this suggestion to shock the valve open. Thank you for the suggestion.


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## Kapinossa (Jan 27, 2022)

The only update today, so far. I tried the batteries directly to the green spade on the gas valve after the pilot was lit for an attempt at shocking it. Also removed the green wire from the gas valve from the control module, before testing with direct battery current.

Tried 2 D cells for 3.16 volts: No lite
Tried 3 D cells for 4.31 volts: No lite
Tried 4 D cells for 6.32 volts: No lite

Also did some moderate valve taping during each test with no light.


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## Lennox65 (Jan 28, 2022)

You seem to have exhausted all of the troubleshooting and it does seem like the problem is in the main burner solenoid. If you can find that part separately from a complete valve, it is easy to change out.


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## Kapinossa (Jan 28, 2022)

I still need to get to the burner area to see if there is anything behind the nozzle.

I was thinking about cracking the gas line exiting the gas valve to see if there is any gas going pass the solenoid but don't like the potential of gas leaking with the pilot flame lit!

Just not sure how to test the gas valve!

Several years ago, I replaced a gas valve on another fireplace and it was not the problem. Just trying to avoid doing that again.
I will attempt to investigate the burner orfice area with an dissasmembly under the logs to get to it.


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## Kapinossa (Jan 28, 2022)

Lennox65 said:


> You seem to have exhausted all of the troubleshooting and it does seem like the problem is in the main burner solenoid. If you can find that part separately from a complete valve, it is easy to change out.


I think I found the correct regulator (NGK-DXV) for the main burner solenoid for my Dexen 750-500 gas valve. Looks like only two anti-tamper screws on front face to remove regulator with a single O ring gasket between it and the valve body. Definitely would be allot easier to change this part instead of the complete valve due to restricted access to loosen pipes (I have changed two before on an older Heat n Glo and not allot of fun).

Just wondering if you had any experience just changing this specific part (not the valve but the regulator) and not having the valve leak at the joint with the new O ring?


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## Lennox65 (Jan 29, 2022)

Kapinossa said:


> I think I found the correct regulator (NGK-DXV) for the main burner solenoid for my Dexen 750-500 gas valve. Looks like only two anti-tamper screws on front face to remove regulator with a single O ring gasket between it and the valve body. Definitely would be allot easier to change this part instead of the complete valve due to restricted access to loosen pipes (I have changed two before on an older Heat n Glo and not allot of fun).
> 
> Just wondering if you had any experience just changing this specific part (not the valve but the regulator) and not having the valve leak at the joint with the new O ring?


Yes, we change them all the time when we do gas conversions. I don't even change the gasket, it is always firmly seated when I remove the regulator and I just put the new regulator on and screw it down. I have never had a leak but you can easily check for leaks with solution.


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## Kapinossa (Jan 29, 2022)

This brings up a good point. If I remove the old regulator. Can I test the unit on the bench?

I know I have 60 ohms across the green spade and valve body ground. Which means the coil of the solenoid is not grounded or shorted. If I apply 3 volts DC to the removed solenoid on the bench, can I see or hear movement?

Maybe should do while I wait for the new part to arrive or before ordering?

Your thoughts.


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## Lennox65 (Jan 29, 2022)

Kapinossa said:


> This brings up a good point. If I remove the old regulator. Can I test the unit on the bench?
> 
> I know I have 60 ohms across the green spade and valve body ground. Which means the coil of the solenoid is not grounded or shorted. If I apply 3 volts DC to the removed solenoid on the bench, can I see or hear movement?
> 
> ...


I don't know if there is any movement other than the voltage energizing a magnet that then holds open a gate that allows the gas to flow through to the main burner.


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## Kapinossa (Jan 29, 2022)

Thanks for your thoughts. Will do some teardown this afternoon to look for a clogged nozzle area.


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## Kapinossa (Jan 29, 2022)

Finished teardown today and I am sure that there is nothing near and in the nozzle exit / orifice to the burner assembly. Pictures attached.

To my surprise the nozzle area leading to the burner had allot of orange / rust like stains on the bottom of nozzle orifice tub.
Picture attached. Not sure what this is about? Maybe allot of moisture in the gas supply and maybe screwed up the gas valve or just an area to collect outside moisture from the very short vent out of the back of the unit?

Anyone seen these kind of stains on a Heatilator fireplace that is less than 5 years old with only a few operating hours?

Moving to the gas valve testing tomorrow. Since there are two test tapes on my Dexten 750-500, I assume one is the supply before being regulated and the second tape for the rehulated exit / gas supply. If my main burner valve is stuck closed, I wonder if there will be any gas coming out of the "out" tap with the pilot flame ON and voltage to the main solenoid? Or will it be closed off just like the main burner line? Anyone with experience on where these taps are in the valve body and what to expect?


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## Lennox65 (Jan 30, 2022)

Kapinossa said:


> Finished teardown today and I am sure that there is nothing near and in the nozzle exit / orifice to the burner assembly. Pictures attached.
> 
> To my surprise the nozzle area leading to the burner had allot of orange / rust like stains on the bottom of nozzle orifice tub.
> Picture attached. Not sure what this is about? Maybe allot of moisture in the gas supply and maybe screwed up the gas valve or just an area to collect outside moisture from the very short vent out of the back of the unit?
> ...


I am not sure what the rust like material is or why it is concentrated in that area.
That depression is the lowest point in the firebox and is filled with cold air when the fireplace is not running. Directly below that is the valve cavity which is filled with warm heated air. There may be condensation forming and collecting there.
The outlet tap on the gas valve is used to check the gas pressure when the main burner is on and running. You would only have gas there if every part of the valve was operating correctly.


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## Kapinossa (Jan 30, 2022)

Lennox65 said:


> I am not sure what the rust like material is or why it is concentrated in that area.
> That depression is the lowest point in the firebox and is filled with cold air when the fireplace is not running. Directly below that is the valve cavity which is filled with warm heated air. There may be condensation forming and collecting there.
> The outlet tap on the gas valve is used to check the gas pressure when the main burner is on and running. You would only have gas there if every part of the valve was operating correctly.


Thank you so much for your input on the outlet tap. I will evaluate the taps today. I will expect that there will be NO gas at the OUT tap since I don't think any is getting to the exit line.


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## Kapinossa (Jan 30, 2022)

As expected, no gas at the "OUT" tap on the gas valve even with solid pilot flame and 1.62 volts at the green spade.

Removed the main burner solenoid / regulator part of the gas valve. Picture below.

Placed 3 volts to green spade of solenoid / regulator part to observe the interior end of this part. Observed small movement of a tab to move off of the adjustment head and when power is removed the part seats back on top of adjustment head. Not sure how this part actually operates to let gas flow through the regulator so I really don't know if this part is actually the failed component? 

Any thoughts on replacing just the regulator or do I need to replace the whole gas valve?


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## Lennox65 (Jan 31, 2022)

Kapinossa said:


> As expected, no gas at the "OUT" tap on the gas valve even with solid pilot flame and 1.62 volts at the green spade.
> 
> Removed the main burner solenoid / regulator part of the gas valve. Picture below.
> 
> ...


Replacing just the regulator has worked for me every time. Although, you could buy the whole valve and try replacing just the regulator. If that doesn't fix it, change the valve.


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## Kapinossa (Jan 31, 2022)

Agree with that approach. I ordered the whole valve instead of just regulator tonight.

Hoping to install just the regulator first to see if that works since it can be done so quickly versus replacing the gas valve.

I am pretty sure my issue can only be in the gas valve assembly, just having this nagging thought that I am missing something but tried everything I could to energize it independently with no success!

I did NOT measure gas supply pressure but I do have a good pilot light and gas available at the valve test tap. In addition, all other gas appliances off of the house gas supply manifold work fine. I don't have a gas guage and decided that a purchase was not required before buying the part. I usually just worry too much, but these units seem to always surprise me so I spent allot of effort before ordering the part. Keeping my fingers crossed!


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## chmau99 (Feb 26, 2022)

Lennox65 said:


> The valve may be stuck and the normal voltage at the green spade may not be enough to open it.
> You can try "shocking" it open by using the back up battery pack with batteries in it. Remove the green wire from the spade.  Disconnect the leads from the battery pack. While the wall switch is on , and the pilot is lit, put one of the leads from the battery pack on the green spade and the other lead on the metal face of the valve body. (for ground) I usually use a battery pack that holds 4 AAA batteries so 6 volts are delivered. If 1.62 is the normal voltage, 3 volts from your battery pack may be enough.


I have the same problem as above.  I tried this and when I used the battery pack, the additional voltage was enough to open the valve and light the fireplace.  When I remove the battery pack though, it goes right back out.  Is it possible to fix the stuck valve or do I need to replace it?  I repeated this process quite a few times to see if that would help but it did not.


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## Kapinossa (Feb 26, 2022)

chmau99 said:


> I have the same problem as above.  I tried this and when I used the battery pack, the additional voltage was enough to open the valve and light the fireplace.  When I remove the battery pack though, it goes right back out.  Is it possible to fix the stuck valve or do I need to replace it?  I repeated this process quite a few times to see if that would help but it did not.


Good luck chmau99. I did change only the regulator and I was still not able to get a main burner gas flow.

I suspect my problem is the gas valve and I am attempting to replace that complete part today after being away for the last two weeks. The regulator is very easy to change out an costs $61 but I purchased the complete valve just in case it was not just the regulator.

Bottom line, I am surprised it is the gas valve on mine but hopefully I can change it out today and post my results. It is a confined location to loosen three gas connections. Looking for work arounds if I can not get my two wrenches on each of the main gas supply and out lines. I have been stalling for a couple of days trying to figure something else out but I am done to a gas valve swap out.


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## Lennox65 (Feb 27, 2022)

chmau99 said:


> I have the same problem as above.  I tried this and when I used the battery pack, the additional voltage was enough to open the valve and light the fireplace.  When I remove the battery pack though, it goes right back out.  Is it possible to fix the stuck valve or do I need to replace it?  I repeated this process quite a few times to see if that would help but it did not.


When you remove the battery pack are you putting the green wire from the wiring harness back on the main burner solenoid spade?


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## Kapinossa (Mar 9, 2022)

Finally success, after almost two months of trying numerous fixes to enable my main burner to light even though I had a solid pilot flame. All of these recommendations attempted were solid thoughts based on normal issues but my situation was unique and required major dissassembly to uncover.

I previosly posted a picture of my valve assembly plate with an area under the burner feed tube to collect water and rust the plate. The picture had a large orange rust area at the nozzle exit line to the burner. It appears water entered the lowest plate of the fireplace and collected in this tub with a height over two inches of water that then entered the gas nozzle and then to the lowest point into the gas valve exit port.

As soon as I loosen the exit line fitting on the gas valve, dirty water dripped out. Also, the filter screen at the exit port was covered with black like mud which I assume is from the lava rocks or dirty water run off. I then assume my main gas valve port was rusted closed or not able to move with it containing water for at least an year or longer.

So I replaced the gas valve and tried to clean out the 12 inch long gas line with compressed air and brushes. Finally, I spent another day trying to remove the majority of the rust on the tub area and nozzle support brackets for part longevity. However, I am trying to figure out how water is entering inside the unit to avoid this problem reoccurring. 

Based on observation of the direct vent on the exterior of the house, the water run off from the fireplace bump-out roof is over shooting the drip edge of the direct vent and MAYBE slashing into the horizontal vent pipe as it hits the various wires / plates of the vent???

A neighbor has my same configuration but he has a 45 degree plate (vinyl siding diffuser) attached to top of direct exit vent. My installation DOES NOT have this plate (TRAP-VSS). His fireplace is fine but mine has water in it. I added this plate on Friday as some insurance but I have NOT observed any water penetration over the last two months while it was disassembled without the plate.

So, I am NOT positive on how water entered my fireplace but my gutters on the area way above the bump out where also changed due to leaf clogging and water run off three years ago. This may be a situation with main home roof runoff onto the bump out roof was at an excessive level of water runoff?

In conclusion, once I broke into the gas line exit of the gas valve there was dirty water present inside the valve. Previously, I tried numerous failed attempts to un-stick the main gas valve with tapping and direct battery voltage to the regulator but all were done without buying unnecessary parts. I would have saved allot of time but was trying not to break into the gas line, if possible. I even tried the new regulator off the new gas valve to avoid changing the entire valve but I was not aware of the real problem of water in the gas valve.

Thanks everyone for their suggestions which provided me confidence to continue troubleshooting and thus final resolution.


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## warmup777 (Mar 9, 2022)

Kapinossa said:


> Finally success, after almost two months of trying numerous fixes to enable my main burner to light even though I had a solid pilot flame. All of these recommendations attempted were solid thoughts based on normal issues but my situation was unique and required major dissassembly to uncover.
> 
> I previosly posted a picture of my valve assembly plate with an area under the burner feed tube to collect water and rust the plate. The picture had a large orange rust area at the nozzle exit line to the burner. It appears water entered the lowest plate of the fireplace and collected in this tub with a height over two inches of water that then entered the gas nozzle and then to the lowest point into the gas valve exit port.
> 
> ...


Congrats! That was quite the saga. Now I'm looking for the satisfying photo of the roaring fire...


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## Lennox65 (Mar 10, 2022)

Kapinossa said:


> Finally success, after almost two months of trying numerous fixes to enable my main burner to light even though I had a solid pilot flame. All of these recommendations attempted were solid thoughts based on normal issues but my situation was unique and required major dissassembly to uncover.
> 
> I previosly posted a picture of my valve assembly plate with an area under the burner feed tube to collect water and rust the plate. The picture had a large orange rust area at the nozzle exit line to the burner. It appears water entered the lowest plate of the fireplace and collected in this tub with a height over two inches of water that then entered the gas nozzle and then to the lowest point into the gas valve exit port.
> 
> ...


Water could definitely be running off that roof and getting back into the fireplace. That shield that you are missing would probably help keep most of the water from dropping straight onto the termination cap, although it's primary function is a heat shield.
You should put a gutter or diverter above the termination cap.


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## Kapinossa (Mar 10, 2022)

Appreciate the suggestion and I have been thinking about it.

One item that comes to mine is that I had the fireplace disassembled for over a month without the added heat shield and have not seen one drop of water inside the fireplace. However, since the collection point is hidden under the floor plate and allot of dissassembly is required to ensure there is no water collection, I have not reassembled yet and will be watching the two days of rain this week for any indications. Of course, there is a potential of wind impact which can be a major variable.  Bottom line, a gutter type collection would definitely add additional margin.

Forgot to include a photo of success, taken of the partial assembled fireplace!

Appreciate everyone's thoughts in trying to resolve my situation. Every comment had merit and was part of the solution.


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