Question:

Pro: I had a Coleman furnace in my old ‘74 Titan MH and I contacted Coleman (which is now RVP) and they sent me Xerox copies of the old manuals for my unit.  I’m sorry, but I no longer have their phone number but I suspect somebody here in the NG can help. Mike

– Hide quoted text — Show quoted text – It indicates Model 8628 on the data plate mounted on the blower housing…but I’ll check it again to be sure. Ooooooops. I checked the Mod number again and you’re right! It is a Model 8623. Thanks again, Dave (Thinking it’s time to make that appointment with the eye doctor)

Response:

<<.. Yes the burner was indeed heavily clogged with rust particles and packed with soot. It is cast iron and has very narrow (.040 and .015) slots cut into the top of it. They were all plugged up. The few times I tried to use it, it would light "violently". Not a smooth controlled ignition. When it blew a ball of fire out the external exhaust port one night…I knew it was time for a overhaul.

<<..         I’ll bet this is all that is needed (except, of course, a good inspection of the combustion chamber and gaskets- but these older furnaces were built pretty heavy, and didn’t rust out very often). A wiring diagram and parts list would be a good start and much appreciated! I can pretty well see how it comes apart and goes back together…though I’ll admit an "Exploded view" is one I hope I never see it in!

        I’ll e-mail them tomorrow, after U have a chance to convert them to e-mailable form. — Chris Bryant Bryant RV Services- http://www.bryantrv.com On RVing-RV TV about RVs, by RVers: http://www.onrving.com

Response:

   I’m afraid I don’t have anything other than a few really bad exploded diagrams for this

Um, Chris, if you don’t mind — when you’re talking about gas furnaces, can you try to find another term besides "really bad exploded" diagrams? <g Sorta conjures up — well, you know… GB in NC

Response:

It indicates Model 8628 on the data plate mounted on the blower housing…but I’ll check it again to be sure.

Ooooooops. I checked the Mod number again and you’re right! It is a Model 8623. Thanks again, Dave (Thinking it’s time to make that appointment with the eye doctor)

Response:

overly rich condition is nearly *always* due to a dirty/rusted/clogged burner.

<snip Thanks for your response Chris. It indicates Model 8628 on the data plate mounted on the blower housing…but I’ll check it again to be sure. Yes the burner was indeed heavily clogged with rust particles and packed with soot. It is cast iron and has very narrow (.040 and .015) slots cut into the top of it. They were all plugged up. The few times I tried to use it, it would light "violently". Not a smooth controlled ignition. When it blew a ball of fire out the external exhaust port one night…I knew it was time for a overhaul. The combustion fan works fine and the unit aknowledges that it is indeed on, by the sail switch closure that allows gas to flow to the burner compartment. It took some adjustment of the switch lever to get it right, which may explain why the unit was seldom used. I’ve cleaned the burner and heat exchanger (what a mess!) and am in process of reassembling. Also replaced both fan shock mounts as the originals were dryed out and deteriorated. Also both fan motors were disassembled, cleaned, lubricated and reassembled. When the time comes, I hope to "bench run" this unit and make whatever "tweaks" and adjustments I need before reinstalling it in the rig. A wiring diagram and parts list would be a good start and much appreciated! I can pretty well see how it comes apart and goes back together…though I’ll admit an "Exploded view" is one I hope I never see it in! Thanks for your interest. Dave

Response:

I’am overhauling a forced air L.P. furnace from a 1968 Winnebago 26′ class A. All the components test good and I’am in the process of disassembly, cleaning, inspection and repairs where necessary. My question is this. Does anyone have a lead on where I might locate a user’s/owners manual or perhaps a shop service manual for this unit? I have nothing to go on at this point however a local R.V. dealer parts dept says some parts are still available but he needs part numbers. He has no listing on a unit this old. The unit shows sign of operating in a very rich (fuel/air) condition but I cant seem to identify a point of adjustment to correct this condition. It all seems to be "automatic".

 <<.. The unit is… Coleman Forced Air Furnace Model: 8628  Code: 769 S/N: 12675272 BTU: 23,000

        I’m afraid I don’t have anything other than a few really bad exploded diagrams for this (which should be a model 8623- not 8629). But..         This is all from memory (the diagram is bad enough that I cannot make out much about it), but..For this type of furnace, an overly rich condition is nearly *always* due to a dirty/rusted/clogged burner. I would be willing to bet that a thorough cleaning- especially of the burner- will be all that is needed. Make sure that the small combustion fan is working. If the gas valve has a capillary tube (rather than a regular thermocouple) going to the pilot, be very careful with it- as these parts are no longer available. About the only thing of any use I might have is a wiring diagram (though I do have a parts list). — Chris Bryant Bryant RV Services- http://www.bryantrv.com On RVing-RV TV about RVs, by RVers: http://www.onrving.com

Response:

I’am overhauling a forced air L.P. furnace from a 1968 Winnebago 26′ class A. All the components test good and I’am in the process of disassembly, cleaning, inspection and repairs where necessary. My question is this. Does anyone have a lead on where I might locate a user’s/owners manual or perhaps a shop service manual for this unit? I have nothing to go on at this point however a local R.V. dealer parts dept says some parts are still available but he needs part numbers. He has no listing on a unit this old. The unit shows sign of operating in a very rich (fuel/air) condition but I cant seem to identify a point of adjustment to correct this condition. It all seems to be "automatic". The gas controller (regulator) is a somewhat "sealed" unit and shows no adjustment points. I’am suspecting possible diaphram problems within the unit but fear dissassembling it and not being able to located the parts for proper reassembly. I feel this unit has a lot of good service life left in it if I can return it to servicable (safe) condition. If I can locate some service and operating specifications for the safe operation of this unit I would be very pleased and greatful for any help anyone may be able to offer. The unit is… Coleman Forced Air Furnace Model: 8628  Code: 769 S/N: 12675272 BTU: 23,000 Thanks for any input regarding this unit. Dave Jacksonville, Florida

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Question:

My old (‘78 rig but don’t know the age of the unit) Coleman furnace ignites just fine but dies after about a minute of burning. I blew out the dust and cleaned the contact points near the blower switch with no improvement. I assume the problem is in the sending unit at the pilot light. (The pilot light stays lit with no problem.)

        Because the pilot stays lit- the thermocouple is O.K. I would look at the high temp limit switch, and the sail switch (if it has one.).         A model number for the furnace would greatly help. — Chris Bryant Bryant RV Services

Response:

My old (‘78 rig but don’t know the age of the unit) Coleman furnace ignites just fine but dies after about a minute of burning. I blew out the dust and cleaned the contact points near the blower switch with no improvement. I assume the problem is in the sending unit at the pilot light. (The pilot light stays lit with no problem.) I assume I can R&R the sensor unit for about the cost of a bench charge by a technician, who would replace the item anyway. I doubt is there is any adjustment that can be made to the unit. Has anyone had a similar problem with their Coleman?

Response:

My furnace woud fire then quit.  Teh problem was a bad regulator at the gas tank.  When replaced it worked fine.  A dealer can check the pressure easily.  Be sure you have at least two other usede of your gas supply on when you try to test it.  Use the water heater, frig and a burner on the stove. If teh pressure drops below the recommended pressure, get a new regulator.   Good luck. – Hide quoted text — Show quoted text – I recently bought a Class C motorhome and it has a 1988 Hydroflame furnace Model DC8232- ( Direct Spark Ignition). The furnace fan starts and runs for 10-15 seconds then the ignitor starts by sparking in the cumbustion chamber, but it doesn’t light or even poof. That tells me that there is probably no gas getting in there. I know that the furnace was cleaned recently and was rarely  used. I can see into the chamber when I took the ignitor out to clean it and the burner looks black, but it appears not to be covered with carbon deposits. The gas line is free of bends or kinks that would stop or inhibit the gas flow. The connections and grounds all look good and clean. I know that it is rare but I believe that the gas valve is bad/faulty. There are two selonids on the top and was wondering how to test ? Could the ignitor board be bad for just the control of  the valve ? Is there a way to test for this ? Is there any electrical components before the gas valve that would tell the valve not to open the gas supply if the fan and ignitor are running ? If bad do I need to replace the entire valve or can I just replace the bad electrical parts ? Is ther a way to test the mechanical parts of the valve. Thanks for your info. and help. Jim Martin Phoenix, AZ 1988 26′ Marathon

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I don’t think that it is the gas regulator valve, because I can easily run all of the other LP appliances at once without a problem.- (4 stove burners the oven the water heater and the refrigerator) When I test the furnace I am trying it with out anything else running and if it were some gas but not enough gas ( which would be a symptom of a bad gas regulator valve) I would think that it would poof  when the ignitor sparks and that would tell me that there is at least some gas getting into the furnace combustion chamber. Let me know if you see a problem with my logic   ? Thanks any way – Hide quoted text — Show quoted text – My furnace woud fire then quit.  Teh problem was a bad regulator at the gas tank.  When replaced it worked fine.  A dealer can check the pressure easily.  Be sure you have at least two other usede of your gas supply on when you try to test it.  Use the water heater, frig and a burner on the stove. If teh pressure drops below the recommended pressure, get a new regulator.   Good luck. I recently bought a Class C motorhome and it has a 1988 Hydroflame furnace Model DC8232- ( Direct Spark Ignition). The furnace fan starts and runs for 10-15 seconds then the ignitor starts by sparking in the cumbustion chamber, but it doesn’t light or even poof. That tells me that there is probably no gas getting in there. I know that the furnace was cleaned recently and was rarely  used. I can see into the chamber when I took the ignitor out to clean it and the burner looks black, but it appears not to be covered with carbon deposits. The gas line is free of bends or kinks that would stop or inhibit the gas flow. The connections and grounds all look good and clean. I know that it is rare but I believe that the gas valve is bad/faulty. There are two selonids on the top and was wondering how to test ? Could the ignitor board be bad for just the control of  the valve ? Is there a way to test for this ? Is there any electrical components before the gas valve that would tell the valve not to open the gas supply if the fan and ignitor are running ? If bad do I need to replace the entire valve or can I just replace the bad electrical parts ? Is ther a way to test the mechanical parts of the valve. Thanks for your info. and help. Jim Martin Phoenix, AZ 1988 26′ Marathon

Response:

It may or may not be the gas regulator, but fortunately making and using a home-made manometer to test it is easy. You simply need about 10 ft. of clear poly flexible tubing with an I.D. to snug-fit over a gas stove burner valve when the burner is removed. The poly tube should be routed from there and fixed in a vertical ‘U’ down and back up the edges of a yardstick (all fixed to a wood plank, or whatever), and left open at the other end. water should be poured into the ‘U’ until it goes at least 8" up each leg, but not under 16" from the top of each leg. When the burner valve is turned on, the gas pressure is read as the difference between the heights of the two water columns. It has been awhile, but 11.5" sounds right. BTW, a high gas pressure DID cause burner blowout in MY furnace that adjusting the regulator corrected. No other appliances had had problems, but once the pressure was correct, the stove burners were easier to adjust at the low end too. Steve – Hide quoted text — Show quoted text – I don’t think that it is the gas regulator valve, because I can easily run all of the other LP appliances at once without a problem.- (4 stove burners the oven the water heater and the refrigerator) When I test the furnace I am trying it with out anything else running and if it were some gas but not enough gas ( which would be a symptom of a bad gas regulator valve) I would think that it would poof  when the ignitor sparks and that would tell me that there is at least some gas getting into the furnace combustion chamber. Let me know if you see a problem with my logic   ? Thanks any way

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Question:

We tried to light our Coleman Furnace this weekend. The pilot lights just fine but the furnace only lit once when we tapped on the switch that controls the gas flow valve (I know there’s a name for this part, but don’t know what it’s called). Now the blower won’t come on either. Help!! B Simpson Camping 101

Response:

Barbara,   It sounds as if you have a blockage in the burner tube (spiders and the such love to make nests in the tube over the winter). Make sure the tube is clean, and if you still have the problem, check the burner orifice, as it can become clogged from sitting around. Don’t clean it by sticking anything in the hole, as you’ll ruin it. Soak it in alcohol (any kind) for a few hours and blow it dry (hair dryer or your breath). Let me know if you need further help. Your friendly RVIA-certified RV Service Tech

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