Gas and Oil Home Heating Furnaces - pilot light won't stay lit
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01-12-02, 05:23 PM
I have a Rheem forced air central heat-A/C unit. Two of them, actually, 1 upstairs, 1 downstairs. About 10 years old. The one upstairs, her pilot light has had to be relit several times over past several weeks. Sometimes it'll go a few days without having to be relit. Tonight, I can't get the pilot light to stay lit. As soon as I let go of the pilot button, the flame goes out. I sat there for 20-30 minutes tonight, and it will not stay lit. Went thru half a pack of matches. I held the button in as long as 5 minutes once or twice, too. Any idea what's wrong?
Thanks.
Thanks.
Sharp Advice
01-13-02, 02:00 AM
Hello Doug and Welcome to the Heating and Cooling Appliance forum and our Do-It-Yourself Web Site.
Most likely the thermocouple needs replacing. However, a ten year old furnace should have an electronic spark or a glow bar ignition. Thermocouple and or Pilot Generator furnaces are usually much older then 10 years.
If your furnace has a constant {always on} burning pilot flame, one of the two parts {T Couple or Pilot Generator} is defective.
The thermocouple is the part the pilot flame heats.
A thermocouple can be identified as having an element type tube at one end and a threaded nut on the other end.
One end of the thermocouple will be directly in the flame of the pilot. The thermocouples other end screws directly into the body of the gas valve or in some cases another part.
Another type of safety device used on heating appliances is a pilot generator. The element end on this part looks similar to that of a thermocouple, except the element end is larger.
A pilot generator can be identified as, usually but not always, having two wire leads. These wires leads, are usually attached directly to the body of the gas valve with small screws. The pilot generators wires can also be attached to a reset device not directly located on the gas valves main body part.
Replacing whichever of the above described parts in a first attempt at correcting the heating appliances problem, is both the easiest and often least expensive option which often solves the problem.
Mentioned below are several other possibilities that may apply.
The pilot flame must be all blue in color. There should not be any yellow color in the pilots flame. The flame should be the correct size to both provide enough heat to the thermocouple or pilot generator and also provide a positive source of ignition for the gas.
It's also possible the magneto head contained within the body of the gas valve or other reset device is defective. The magneto head is the part the thermocouple threads into. The magneto part may or may not be individually removable and replaceable on all types of gas valves or remotely located safety devices.
Keeping in mind the reason the heating appliance may not operate as described and or mentioned above, consider the possibility there may be a short or grounding in any part or section of the wiring system or thermostat.
Most likely but not always, simply replacing the safety element {Thermocouple or Pilot Generator} resolves the problem. Try replacing one of these parts first, depending on which part applies to the heating appliance you have.
Suggestions:
Read the manufacturers online web site for product information, problem possibilities, causes and solving methods, part locations, disassembly, reassembly methods, repair proceedures and instructions, pictorials and schematics, which may be available online.
Other professionals replying within this forum, may have alternate solutions, suggestions, advice and or opinions and or test and repair methods and proceedures. Check back several times.
Read the RECENT postings & ARCHIVES, within this forum, for other postings on this topic and the replies offered.
Regards & Good Luck
Forum Moderator
TCB4U2B2B Company Enterprises.
Fast, Fair, Friendly & Efficient.....:D
Energy Conservation Consultants & Gas Appliance Diagnostics Technician.
Most likely the thermocouple needs replacing. However, a ten year old furnace should have an electronic spark or a glow bar ignition. Thermocouple and or Pilot Generator furnaces are usually much older then 10 years.
If your furnace has a constant {always on} burning pilot flame, one of the two parts {T Couple or Pilot Generator} is defective.
The thermocouple is the part the pilot flame heats.
A thermocouple can be identified as having an element type tube at one end and a threaded nut on the other end.
One end of the thermocouple will be directly in the flame of the pilot. The thermocouples other end screws directly into the body of the gas valve or in some cases another part.
Another type of safety device used on heating appliances is a pilot generator. The element end on this part looks similar to that of a thermocouple, except the element end is larger.
A pilot generator can be identified as, usually but not always, having two wire leads. These wires leads, are usually attached directly to the body of the gas valve with small screws. The pilot generators wires can also be attached to a reset device not directly located on the gas valves main body part.
Replacing whichever of the above described parts in a first attempt at correcting the heating appliances problem, is both the easiest and often least expensive option which often solves the problem.
Mentioned below are several other possibilities that may apply.
The pilot flame must be all blue in color. There should not be any yellow color in the pilots flame. The flame should be the correct size to both provide enough heat to the thermocouple or pilot generator and also provide a positive source of ignition for the gas.
It's also possible the magneto head contained within the body of the gas valve or other reset device is defective. The magneto head is the part the thermocouple threads into. The magneto part may or may not be individually removable and replaceable on all types of gas valves or remotely located safety devices.
Keeping in mind the reason the heating appliance may not operate as described and or mentioned above, consider the possibility there may be a short or grounding in any part or section of the wiring system or thermostat.
Most likely but not always, simply replacing the safety element {Thermocouple or Pilot Generator} resolves the problem. Try replacing one of these parts first, depending on which part applies to the heating appliance you have.
Suggestions:
Read the manufacturers online web site for product information, problem possibilities, causes and solving methods, part locations, disassembly, reassembly methods, repair proceedures and instructions, pictorials and schematics, which may be available online.
Other professionals replying within this forum, may have alternate solutions, suggestions, advice and or opinions and or test and repair methods and proceedures. Check back several times.
Read the RECENT postings & ARCHIVES, within this forum, for other postings on this topic and the replies offered.
Regards & Good Luck
Forum Moderator
TCB4U2B2B Company Enterprises.
Fast, Fair, Friendly & Efficient.....:D
Energy Conservation Consultants & Gas Appliance Diagnostics Technician.
fjrachel
01-13-02, 04:40 AM
Change the themocouple and clean the pilot orifice......
01-13-02, 05:45 PM
A new thermocouple worked! It fired up in just 20 seconds... Flame is all blue. Thank you two very much. I had to buy one that was 24" long instead of 18", but it works just fine. By the way, the information label says 1985, so this unit is 16 years old, going on 17, not the 10 years that I originally stated. Thanks again!