Gas and Oil Home Heating Furnaces - Sick Lennox (PLEASE HELP)
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jhinferrmashun
12-23-06, 12:47 PM
I have a natural gas Whisperheat by Lennox furnace that is approximately 15 years old.
I previously had trouble with the pilot lighting and going out before ever lighting the main burners. I checked the flame sensor and found it to be corroded and the porcelain portion cracked, so i replaced that. The furnace ran fine for two to three weeks but now I am having a similar problem. Now, the pilot lights, the main burners light and burn for a little while (usually 4-10 seconds), and then go out.
The furnace doesn't attempt to relight on its own. For a while if I stood there and turned the power to the furnace off and back on it would again light the pilot then the main burners and go out. But, usually after a few tries it would take off and run fine for a day or two. Now though, I cannot get it to run. I looked again at the flame sensor and it looks fine, and the connections are clean and secure.
It is down to 57 degrees inside now and I can't afford to have a service guy out right now so any help would be GREATLY appreciated.
I previously had trouble with the pilot lighting and going out before ever lighting the main burners. I checked the flame sensor and found it to be corroded and the porcelain portion cracked, so i replaced that. The furnace ran fine for two to three weeks but now I am having a similar problem. Now, the pilot lights, the main burners light and burn for a little while (usually 4-10 seconds), and then go out.
The furnace doesn't attempt to relight on its own. For a while if I stood there and turned the power to the furnace off and back on it would again light the pilot then the main burners and go out. But, usually after a few tries it would take off and run fine for a day or two. Now though, I cannot get it to run. I looked again at the flame sensor and it looks fine, and the connections are clean and secure.
It is down to 57 degrees inside now and I can't afford to have a service guy out right now so any help would be GREATLY appreciated.
Jay11J
12-23-06, 06:48 PM
Did you check the wire from the flame sensor to the control to make sure it's ok, and no bad connections?
mbk3
12-23-06, 07:07 PM
Is it equipped with a Johnson module? They have been problamatic
Muggle
12-23-06, 08:26 PM
The Lennox whisperheat is prone to heat exchanger failures.
Cracks are potentially dangerous, as they can result in flame rollout and let combustion gasses into the air stream.
So I suggest that you call a qualified technician to inspect the unit and deal with the ignition issue instead of changing out parts until it works. Nobody can diagnose this problem over the Internet. Your safety is worth more than that of a service call.
Run space heaters temporarily, or turn on the oven if it's electric. (gas = CO risk)
Cracks are potentially dangerous, as they can result in flame rollout and let combustion gasses into the air stream.
So I suggest that you call a qualified technician to inspect the unit and deal with the ignition issue instead of changing out parts until it works. Nobody can diagnose this problem over the Internet. Your safety is worth more than that of a service call.
Run space heaters temporarily, or turn on the oven if it's electric. (gas = CO risk)
jhinferrmashun
12-23-06, 10:47 PM
I looked at the wire and the connections; all seem to be clean and secure
Did you check the wire from the flame sensor to the control to make sure it's ok, and no bad connections?
Did you check the wire from the flame sensor to the control to make sure it's ok, and no bad connections?
jhinferrmashun
12-23-06, 10:48 PM
The control thing says Robertshaw Controls Company on it
Is it equipped with a Johnson module? They have been problamatic
Is it equipped with a Johnson module? They have been problamatic
jhinferrmashun
12-23-06, 10:52 PM
Is it likely for a cracked heat exchanger to cause the symptoms I'm having? Also, thanks for the warning.
The Lennox whisperheat is prone to heat exchanger failures.
Cracks are potentially dangerous, as they can result in flame rollout and let combustion gasses into the air stream.
So I suggest that you call a qualified technician to inspect the unit and deal with the ignition issue instead of changing out parts until it works. Nobody can diagnose this problem over the Internet. Your safety is worth more than that of a service call.
Run space heaters temporarily, or turn on the oven if it's electric. (gas = CO risk)
The Lennox whisperheat is prone to heat exchanger failures.
Cracks are potentially dangerous, as they can result in flame rollout and let combustion gasses into the air stream.
So I suggest that you call a qualified technician to inspect the unit and deal with the ignition issue instead of changing out parts until it works. Nobody can diagnose this problem over the Internet. Your safety is worth more than that of a service call.
Run space heaters temporarily, or turn on the oven if it's electric. (gas = CO risk)
jim-connor
12-24-06, 10:34 AM
Agree with Muggle. You need a pro to look at it. There is a high probability your heat exchanger is cracked.
Muggle
12-24-06, 11:32 PM
A bad heat exchanger will not cause the problem you are experiencing.
The G20 (whisperheat) has a 20 year warranty on the heat exchanger if it's bad, but it doesn't cover labour.
I don't think it's uncommon to have to replace an ignition module on a 15 year old furnace. (it could be that) Either way, if the system hasn't been inspected for more than a year, it's due.
The G20 (whisperheat) has a 20 year warranty on the heat exchanger if it's bad, but it doesn't cover labour.
I don't think it's uncommon to have to replace an ignition module on a 15 year old furnace. (it could be that) Either way, if the system hasn't been inspected for more than a year, it's due.
jim-connor
12-25-06, 07:44 AM
IMO circuit boards become suspect after 8 years or so. The usual failure is caused by bad relays or capacitors (I'm not talking about the blower capacitor). These bad components, can produce constant or intermittant problems.
Anyway, a furnace with a cracked HX and bad electronics will cost a fair amount to fix. It may not be worth pouring lots of money into a 15 year old unit. You may want to compare the cost of a new furnace.
Anyway, a furnace with a cracked HX and bad electronics will cost a fair amount to fix. It may not be worth pouring lots of money into a 15 year old unit. You may want to compare the cost of a new furnace.
nomore9to5
12-25-06, 09:35 AM
chances are pretty slim that your gonna find a whisper heat hx, and its gonna cost an arm and a leg for someone to want to do it.
Muggle
12-25-06, 03:10 PM
chances are pretty slim that your gonna find a whisper heat hx, and its gonna cost an arm and a leg for someone to want to do it.
They have a 20 year warranty, so the only real cost is labour. (several hundred $ though)
I believe that they are still available.
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Call a Lennox dealer.
They have a 20 year warranty, so the only real cost is labour. (several hundred $ though)
I believe that they are still available.
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Call a Lennox dealer.
jhinferrmashun
01-05-07, 09:22 PM
Thanks to everyone for your suggestions and help. I finally broke down and got a guy in to look at it. SEVERAL cracks in the heat exchanger.