Monessen NB24 Log Set - Pilot will not light

  • Active since 1995, Hearth.com is THE place on the internet for free information and advice about wood stoves, pellet stoves and other energy saving equipment.

    We strive to provide opinions, articles, discussions and history related to Hearth Products and in a more general sense, energy issues.

    We promote the EFFICIENT, RESPONSIBLE, CLEAN and SAFE use of all fuels, whether renewable or fossil.

jkuhn

New Member
Mar 9, 2017
15
Blacksburg, VA
I have a Monessen NB24 logset and the pilot light will not light after trying to purge the air out of the line for a long time (We have tried doing it probably 10 times and each time for 10 minutes or more). After doing some reading I discovered that the pilot assembly may need to be replaced, I ordered this pilot light assembly and installed it. After this was installed we tried again multiple times to purge the air out of the line to light the pilot. We now get a small blue flame but it goes out almost immediately. I then researched and bought a can of compressed air and some pipe cleaners to clean all the necessary places, still no luck. This log set was in the house when I bought it in December 16', so I do not know if the previous owners had any issue out of it or not but it definitely has been used.

So my next areas to see about replacing are either the shut off valve on the side of the mantle or the regulator outside on the tank... Anyone have any ideas on this so I don't just keep throwing money at it?

Any help is appreciated!!

I have also attached the manual I found online for the log set for reference.

Edit: It is an LP unit.

Thanks!
Jennifer
 

Attachments

  • MONESSEN NB18 24.pdf
    5.8 MB · Views: 655
I have a Monessen NB24 logset and the pilot light will not light after trying to purge the air out of the line for a long time (We have tried doing it probably 10 times and each time for 10 minutes or more). After doing some reading I discovered that the pilot assembly may need to be replaced, I ordered this pilot light assembly and installed it. After this was installed we tried again multiple times to purge the air out of the line to light the pilot. We now get a small blue flame but it goes out almost immediately. I then researched and bought a can of compressed air and some pipe cleaners to clean all the necessary places, still no luck. This log set was in the house when I bought it in December 16', so I do not know if the previous owners had any issue out of it or not but it definitely has been used.

So my next areas to see about replacing are either the shut off valve on the side of the mantle or the regulator outside on the tank... Anyone have any ideas on this so I don't just keep throwing money at it?

Any help is appreciated!!

I have also attached the manual I found online for the log set for reference.

Edit: It is an LP unit.

Thanks!
Jennifer


Can you adjust the pilot flame? There may be a screw on the front of the gas valve to allow you to do this.
If the flame doesn't contact the thermocouple for a minimum of 30 seconds, the pilot won't stay lit.
 
Can you adjust the pilot flame? There may be a screw on the front of the gas valve to allow you to do this.
If the flame doesn't contact the thermocouple for a minimum of 30 seconds, the pilot won't stay lit.

I am not sure if there is a screw to adjust it, I will take a look tonight. The flame doesn't stay lit for more than a second, it is like a flash of a flame and that is it.
 
How to Inspect a Gas Furnace Pilot Light
https://www.thespruce.com/inspect-a-gas-furnace-pilot-light-1824774

The above appears to be a decent description to help guide you.

Are you holding down the button long enough? When lighting the pilot do you have a good flame? If not you can try to adjust the pilot or better first to clean your pilot tube first.


This appears to be a decent video for checking pilot tubes etc.
 
How to Inspect a Gas Furnace Pilot Light
https://www.thespruce.com/inspect-a-gas-furnace-pilot-light-1824774

The above appears to be a decent description to help guide you.

Are you holding down the button long enough? When lighting the pilot do you have a good flame? If not you can try to adjust the pilot or better first to clean your pilot tube first.


This appears to be a decent video for checking pilot tubes etc.


I have watched that video as well, the only bad part is it is on a pilot on a gas furnace, I do not know where the pilot orifice is at on my gas log set. I have held down the knob in the pilot position for 10+ minutes about 10 times already and no luck... We it lights it is like a flash of flame and then it goes out, which is telling me there just is not enough propane coming through which is why I was thinking it might be the regulator outside or the shut off valve inside. I will look for an adjustment screw when I get home this evening and see if there is one on the unit.
 
The parts will look similar.

Do you have a good pilot flame? Does the flame cover the thermocouple-thermopile? Is it lazy or is it too strong where it flies past the T-couple?

It is never a bad idea especially with propane to know the regulator pressure.
 
The parts will look similar.

Do you have a good pilot flame? Does the flame cover the thermocouple-thermopile? Is it lazy or is it too strong where it flies past the T-couple?

It is never a bad idea especially with propane to know the regulator pressure.

I know the parts will look similar, I just do not know where to find it. Where the log set connects to the propane line it has a right angle connection, do I need to remove that to see if that is where the orifice is at?

I do not have a flame, it will not stay lit at all, it goes out in less then a second once it lights.
 
When lighting it while holding the button do you have a good flame as I described?
 
I am asking you the questions as simply as I can for reasons. You can have a good flame and it goes out right away also.

What is your gas pressure going to valve, is your pilot tube and orifice clean and can you adjust the pilot flame? That is where imo you need to go next.
 
I am asking you the questions as simply as I can for reasons. You can have a good flame and it goes out right away also.

What is your gas pressure going to valve, is your pilot tube and orifice clean and can you adjust the pilot flame? That is where imo you need to go next.

I am sorry for any misunderstanding, I just felt like I had already answered regarding the flame.

I do not know what the pressure is going to the valve, how would I figure that out?

I replaced the whole Pilot/ODS Assembly so I know it is not clogged. I will have to see tonight when I go home if the tube can be removed to blow it out with compressed air and also if there is an adjustment screw on the logset for the pilot light.
 
As the Youtube video showed the orifice may be clogged. There probably is a pilot adjustment on the valve. You need a manometer to check gas pressure. They can be inexpensive and can be made at home for even less. Many good videos etc to check on these also. Is this your only propane appliance? Good luck!
 
As the Youtube video showed the orifice may be clogged. There probably is a pilot adjustment on the valve. You need a manometer to check gas pressure. They can be inexpensive and can be made at home for even less. Many good videos etc to check on these also. Is this your only propane appliance? Good luck!

Ok, I will check all of those things again tonight. This is my only propane device, I would like to get it running for a secondary heat source incase we lose power again with the threat of winter weather this weekend.

Thank you for your suggestions! I will report back tomorrow :)
 
I was asking if it was the only propane device to ask if you were having problems with the other ones. Problems with propane pressure is a common problem.
 
I was asking if it was the only propane device to ask if you were having problems with the other ones. Problems with propane pressure is a common problem.

Yeah, I figured that. It would be easier to troubleshoot if I did have another device that was working. That is good to know it is a common problem, I might end up just having to have someone come take a look at it if I can't figure anything out. I was really trying to avoid the service call cost though.
 
This is going to seem like a stupid question, but just to confirm. Have you checked the gauge on the tank to be sure it has gas in it?
 
Darn, you're to fast for me. I was going to edit my reply to add (and the valve is open)?

Yes, the valve is open on the tank and on the side of the mantle when trying to light the pilot.

Here is a picture of what I think it's the pilot light screw (adjustment). Can anyone confirm if it is?
 

Attachments

  • IMG_6247.JPG
    IMG_6247.JPG
    86 KB · Views: 298
Yes, the valve is open on the tank and on the side of the mantle when trying to light the pilot.

Here is a picture of what I think it's the pilot light screw (adjustment). Can anyone confirm if it is?
That's the pilot adjustment. Right next to "pilot". Remove the screw and CCW will probably increase pilot if it is able to.
 
So in your picture where you are trying to show the pilot adjustment what is that directly to the right of it? Is that the thermo couple? It looks like a nova 820 valve but ussually the thermo couple goes into the hole on the back of the valve. A tc not connected properly would account for the pilot shuting down immediately. Other than that we need pressures and valve resistance readings.