Coleman 4023-5871 Furnace

RV Type: Motorhome
Model: Winnebago Indian
Year: 1974
Description of Problem: Can’t light the furnace pilot (Coleman 4023-5871, looks great otherwise and worked just a few month ago when it wasn’t needed; the blower works great). Opened it, apparently the thermocouple is broken. Would like to purchase a replacement – or maybe I should replace the entire valve assembly? Please advise.Thank you!

Our Answer

Hi: Well the gas valve is very likely no longer available. Does the pilot work as long as you hold the button in?

If so, the broken thermocouple is probably all you need to repair. If the pilot flame does not keep the t-couple hot of course the flame will go out, the power from the t-couple replaces your finger on the safety valve to keep the valve open, by passing a very small current through a solenoid coil in the valve to keep it open.

Any t-couple will work as long as it is long enough to sit in the flame and mechanically connect to the gas valve. They all provide the same voltage about 18 to 29 millivolts. The physical connection to the gas valve (most are very similar), should never be over-tightened in the threaded portion, a rule of thumb is finger tight plus a MAXIMUM of 1/4 turn. If the pilot stays lit then the gas valve should work OK, they rarely are the problem thankfully.

Hope this will help. Universal t-couple are usually available, but as I am closed for the season and do not have my catalogues I cannot tell you which one to purchase.

Bob Burnside
Stevenson RV

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8 Responses to Coleman 4023-5871 Furnace

  1. Grace says:

    Hello, Wanting to know if you were able to get your Coleman furnace pilot lit, and what part you replaced or repaired. Have a 1973 Silver Streak with a Coleman Furnace 4030 that the coil gets red, but pilot won’t light. Did replacing just the thermocouple work? Please advise. I am unable to locate the pilot to manually light per operating instructions.

  2. Bob says:

    Hi: The pilot burner is directly in front of the glow coil you see growing red, Your gas valve is electrically operated and should be releasing gas to the pilot burner when this coil is glowing. The pilot burner may be plugged and not allowing gas to escape, therefore no flame. The pilot can be cleaned but must be done by a person who knows how to remove and clean it, NOTHING SHOULD BE FORCED THROUGH A PILOT ORIFICE. It should be cleaned with compressed air and alcohol. If the pilot is clean and no gas comes the gas valve may be faulty. The thermocouple is only used to maintain the pilot flame once it lights, as I said before it replaces your finger on the safety valve button. The pilot will not light manually if no gas is present, so if the glow coil is working it must be a gas issue if it fails to light.

  3. chris says:

    Why when my colman 4023 5871 gets hot runs for about hour to 2. Hours then wont again pilot stays on just wont release lp again it cools down same then again.

  4. Bob says:

    Hi Chris. The gas valve is controlled by the wall thermostat, and of course the pilot being maintained. If the pilot stays on the gas valve is energized by the micro voltage applied by the therm-o-couple in the circuit. The only other thing should be the wall thermostat which could be faulty and staying in the off position until the room or surroundings get really cold before it activates again. This could be a sticky thermostat. One test to try is to disconnect the t’sat and use the wires as a temporary switch to turn the furnace on and off if this works every time, replace the t’stat.

  5. Chuck Coates says:

    Can’t light the Pilot light on a 4235AColeman R.V. Furnace, any help please????

  6. Bob says:

    Hi Chuck: If I am correct that model furnace has a glow coil for ignition, also called an igniter coil part #8616-1061 When you look through the sight glass do you see any sign the coil is working, it should have a fair glow to it, and if it is are you sure you are getting gas into and through the pilot itself. You only need two things for the pilot to work, gas and ignition source if either one is missing you have a problem. Make sure your pilot orifice is passing gas, but never pass anything through it but air and or alcohol to clean it. No wires of any sort, air pressure and alcohol work the best. Let me know

  7. Neil Waterman says:

    i have the same furnace the flame goes out when i release the red button.Sometimes the gas valve hammers when it tries to start up.The sail switch is broken e 22 written on the side.Can you suggest one that is compatable ,the switch is broken high limit .#2061f29-48c3v f14-3 4030 308. This is an older furnace and i cannot get any parts.Can please suggest some compatable parts.I think the thermostat is not working continuesly. Can you also suggest a compatable one. coleman rv furnace 4030 code # 889 serial # 47303852.

  8. Bob says:

    Hi Neil: Well I do not have all the parts you require but I do have the High limit which is Coleman part number 4023-3091 and is rated at 220-180 for temp rating.. The sail switch is a micro switch with a paddle, I do not have one but a lot of switches would work. They just depend on the air-flow to make up to allow the burner to start after the motor starts of course.The flame going out with the release of the red butt could be one o 2 or 3 things. Is the pilot flame large enough and enveloping the end of the thermocouple, there could be a blockage reducing your flame size in the pilot burner. NEVER CLEAN THE PILOT WITH ANYTHING OTHER THAN ALCOHOL AND AIR. If you do you could enlarge the orifice and then you would have problems. . If the flame seems large enough remove the thermocouple from the safety valve and measure the voltage produced by the thermoouple with a millivolt meter. The voltage should be between 017 to 030 milli-volts. If it is, clean the end of the t-couple with paper or a lint free cloth and put it back in-the safety valve. Again do not over-tighten the t-couple, turn it in finger tight plus a 1/4 turn with a small wrench the wiring in the bottom of that socket could be damaged if over-tightened. If after having done that the flame still does not stay lit it would mean a new safety valve, they are not repairable.. I do not know which valve you have they used several for operational but the gas valves were supposed to be the same on all. It should be a 4023A3211 valve.. It may be difficult to find, I do not have one. Insofar as your wall tstat is concerned any one , non electronic would work. It is only a switch turned off and on by a bi metal, or spring operated thermal sensor.

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