77 Boler Suburban furnace help

[Michael Collins]

Firstly, sorry for all the recent questions. I bought this Boler a few weeks back after it sat for a very long time. I've slowly gone through it and got to the furnace recently. The suburban furnace lights fine and holds the pilot fine, but it doesn't throw much heat at all. I ran it for 2 hours the other night and i went back into the trailer to find it kind of cold inside. The flame in the furnace is more of a yellow than a blue flame. If i turn the dial clockwise it will put the flame out after the dial is turned 3/4 way around. Is there a way to adjust the flame and get more heat out of this thing? I think it's a 6000 btu model, but i could be wrong. Thanks

[Bill K]

I would check the air intake and exhaust as it sounds like the combustion air is restricted. Look for a wasp nest or something like that.

Bill K

Firstly, sorry for all the recent questions. I bought this Boler a few weeks back after it sat for a very long time. I've slowly gone through it and got to the furnace recently. The suburban furnace lights fine and holds the pilot fine, but it doesn't throw much heat at all. I ran it for 2 hours the other night and i went back into the trailer to find it kind of cold inside. The flame in the furnace is more of a yellow than a blue flame. If i turn the dial clockwise it will put the flame out after the dial is turned 3/4 way around. Is there a way to adjust the flame and get more heat out of this thing? I think it's a 6000 btu model, but i could be wrong. Thanks

[Eddie Longest]

Are your range burners working properly. If those burners are also weak you may have a bad regulator. Is your propane tank full?
Eddie

[Michael Collins]

Range burners work fine so i don't think it's that, and the tank is at least 1/3 full. I'll check the air and exit routes from the outside. I was wondering if there was a way to adjust the air fuel mixture for the flame on the burner?

[kevin61]

I was having the same problem when I first purchased my Boler. It turns out that the jet for the main burner was blocked. I simply removed the assembly and gave it a good cleaning.

If you have the same model of furnace as my Boler it should operate as in this video.

http://www.youtube.com/profile?user=kevinh.../21/Oda6xdhXoo0

[Michael Collins]

Thanks Kevin, i'll try and figure out how to take the main burner out. If that's your vid, thank you very much.

I was having the same problem when I first purchased my Boler. It turns out that the jet for the main burner was blocked. I simply removed the assembly and gave it a good cleaning.

If you have the same model of furnace as my Boler it should operate as in this video.

http://www.youtube.com/profile?user=kevinh.../21/Oda6xdhXoo0

[Michael Collins]

Ok, so i used some compressed air and a vaccuum and cleaned out the main burner and the furnace gets very hot now. The flame is bright blue and sounds like a jet, so i'm happy about that. I still have one problem though, i can't dial down the flame, it just hits a point and goes out. I'd estimate it's when the dial is at about 1/4 from the low setting, then it makes a popping sound, and goes out. Do you guys think this dial is hooped? There are 4 screws where it appears i can take the valve out, but i'm scared i might wreck something. Any ideas?

[Michael Collins]

Ok, so i removed the 3 screws that holds the thermostat knob and took a look inside there. There is a little copper wire coiled up inside, with a spring and a rubber diaphram in behind. I degummed the copper coil insdie with some brake cleaner and put everything back together. The adjustment hasn't changed, i can't dial down the flame at all without it going out all together with a popping sound. The sound is coming from in behind the adjustment knob.

I have another question though, the copper coil wire that was inside the knob i removed runs down to below the furnace with a large solid copper tube "size of a pencil". I'm starting to think this might be a sensor for the thermostat?? If i set it to medium will this furnace sense the cold and kick in when required, or am i supposed to dial the flame down manually? Can anyone help? My furnace is similar to Kevin's in his video, except mine has a screw cap instead of a viewing window. Thanks

[E Dyck]

The copper tube usually mounted on the exterior is room temperature sensor. The furnace is either on or off, the flame does not get higher or lower. When the the sensor says it's too cold it turns on, when it get's hot enough it turns off.

[Michael Collins]

Thanks for the reply. If that's the case then i think my furnace is working correctly, because i can't dial down the flame. When i actually do use it i'll set it to medium when it's cold and see if it cuts in and out. Thanks again for all the help.

[Rick G]

Thanks for the reply. If that's the case then i think my furnace is working correctly, because i can't dial down the flame. When i actually do use it i'll set it to medium when it's cold and see if it cuts in and out. Thanks again for all the help.

I have been working on my furnace (an old Wagon Master gravity heat model) this winter, and it has a current Maxitrol control module. My brother, who is a commercial natural gas salesman, confirms that the furnace is either on or off, and its state is controlled by the pencil-type temperature sensor you described, which mine also has. I found that I could control somewhat the heat that the furnace gets to when running as well as the ultimate room temperature, by placement of the temperature sensor. Last year, when the temperature sensor was installed down near the trailer floor inside the cabin, the furnace would get insanely hot when running (I burned my arm while sleeping) and the temperature dial could only be set to about 1 1/2 out of 10 for the trailer to be nice and warm even when the outside temp was below freezing. When I reinstalled the furnace this winter, I put the temperature sensor above the furnace exhaust pipe, inside the cabinet out of the way, so that it would get warmer faster. I am not sure if that will be the final resting place, but now the furnace turns itself off and on much more frequently (so the furnace does not get as hot each time) and I need to put the temperature dial up to about 7 out of 10 to get the trailer comfortable. I haven't camped with it yet in this new position.

So, you can see that the placement of the temperature sensor may affect the performance of your furnace a lot.

Lots of fun,
Rick G in Alberta

[Michael Collins]

Thanks Rick. My temperature sensor is down low on the floor and i've noticed the copper line that runs to it from the thermostat knob is only maybe 6" long. I could put it inside the furnace cabinet a little higher, or maybe on the outside of the cabinet right beside it, but there's not enough copper line for me to extend it any further. Thanks for the help though because i really wasn't sure if it was a thermostat model or not.

Mike

I have been working on my furnace (an old Wagon Master gravity heat model) this winter, and it has a current Maxitrol control module. My brother, who is a commercial natural gas salesman, confirms that the furnace is either on or off, and its state is controlled by the pencil-type temperature sensor you described, which mine also has. I found that I could control somewhat the heat that the furnace gets to when running as well as the ultimate room temperature, by placement of the temperature sensor. Last year, when the temperature sensor was installed down near the trailer floor inside the cabin, the furnace would get insanely hot when running (I burned my arm while sleeping) and the temperature dial could only be set to about 1 1/2 out of 10 for the trailer to be nice and warm even when the outside temp was below freezing. When I reinstalled the furnace this winter, I put the temperature sensor above the furnace exhaust pipe, inside the cabinet out of the way, so that it would get warmer faster. I am not sure if that will be the final resting place, but now the furnace turns itself off and on much more frequently (so the furnace does not get as hot each time) and I need to put the temperature dial up to about 7 out of 10 to get the trailer comfortable. I haven't camped with it yet in this new position.

So, you can see that the placement of the temperature sensor may affect the performance of your furnace a lot.

Lots of fun,
Rick G in Alberta