Lennox lemon, always quitting - http://www.hvacmechanic.com/ Forums
Original message
| chicapet
 |  "Lennox lemon, always quitting"
, posted Wed 30 Apr 07:46  
Just wondering where Yuri is located? I have a 1999 installed Lennox 80UHG2-75a-3 #6399l-01470 that is serviced every year. In the past it has had high limits and flame sensor replaced, gas flow turned down to one inch and recently turned back up to 3.5 inches, Used up four ignitors this winter and circuit board, now has orginal board that service man still had and put back. Sometimes exhaust fan starts and quits, currently ignitor not glowing. If shut off long enough, eveything seems to reset, ignitor worked this morning, then flame quit, now ignitor not working. long reset worked on saturday. flame sensor was cleaned on friday the 18th of april.
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Replies:
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| chicapet
| "Re(1):Lennox lemon, always quitting" , posted Wed 30 Apr 19:56
I live in Toronto, I try to clean electronic filter monthly, have long haired dog, a/c coils were clogged once, now check yearly and vacuum. Latest tech. checked temperature difference. OK. Has hottest lennox high limit switch as i was told boxy discharge ducting was a fault. During ignitor problems, i was lighting furnace with bbq lighter(turned on before gas flow), tech. offered to leave exhaust fan jumpered on and blew fuse, looked for shorts everywhere, decided that the condensate a/c pump installed by lennox was shorting or something. It was plugged into a plug that was fed from furnace 120 supply. I looked at power supply today, it is old bx cable with aluminum ground strip to were old switch was and then a wire to furnace. i could put a seperate ground wire to a ground that i know is direct to panel. It came on on its own eventually this morning. Flashed every code going while tech was here two weeks ago.
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| | yuri
| "Re(2):Lennox lemon, always quitting" , posted Wed 30 Apr 20:12:
Check my latest post 6 above yours for grounding info and procedure, "Info for Marchvac and other techs". Sounds like yours may be the problem. Maybe it is that orange colored air TO has, just joking. Looks orange when the plane is landing.
Yuri
[this message was edited by yuri on Wed 30 Apr 20:14] |
| | chicapet
| "Re(3):Lennox lemon, always quitting" , posted Fri 2 May 14:19
Furnace quit again today at lunch time, code led 2 flashing slow, led 1off, primary or secondary limit switch open. reset and it started right up. took cover off to get Yuri voltages and it quit again. Tech coming tomorrow to replace exhaust fan tube and vacuum swtich. Results of neutral to C tests with analog meter, furnace idle needle barely moved, indoor blower operating 0.3 volts ac, CAI and ignitor couldn't do because it quit before i could get that far. Furnace voltage 120v ac. Where do i put my probe to test for ground resistance? do i discounect the ground wire that is attached to the sheet metal that the board is attached to? Thank you
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| | yuri
| "Re(4):Lennox lemon, always quitting" , posted Fri 2 May 17:04
On the board above the terminal strip there should be a white Molex connector with 12 wires coming out of it. One of them should be green/ground. With the power OFF to the furnace you may be able to put your meter probe into that socket and try running a wire from a copper water line and check for continuity with them. You can try putting a paper clip into that socket if your meter probe won't EASILY fit.
Yuri
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| | chicapet
| "Re(5):Lennox lemon, always quitting" , posted Sat 3 May 09:52
i was able to put probe into green wire. i got 0 ohms from there to where that wire grounds against a tranformer,0 to sheetmetal plate board attaches to,0 to 120 volt ground wire. and 0 to copper pipe at hot water heater using probes only. unit was off from 5am until 930am. when i turned it back on, ignitor turned on but no gas, no ignitor stays off.
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| | yuri
| "Re(6):Lennox lemon, always quitting" , posted Sat 3 May 13:36
Cannot be of more help without being there. With all the jumpering and board switching etc it is hard to imagine what has been going on. I would get Marchvac out to look at it as he is very good with Lennox units. You will have to pay him of course. Sounds like you may need some ductwork advice also.
Yuri
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| | marchvac
| "Re(7):Lennox lemon, always quitting" , posted Sun 4 May 00:29
Thanx Yuri. I think that there was a lot of parts changing going on. Another thing that I didn't like was that the one tech turned the gas down to one inch. I hope that the heat exchanger didn't get carboned up.
Be careful sometimes you don't get a second chance
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| | yuri
| "Re(8):Lennox lemon, always quitting" , posted Sun 4 May 10:22:
The ductwork is a major problem. Increasing the limit control rating is taboo. The heat exchanger may be overstressed and on its way out. May be cheaper and better to buy a new furnace and solve the ductwork problem as it is not going to work well in the long run. Apparently these ECM motors don`t like very undersized ductwork and may cut out. My co-worker has a house with small ducts and our tech guy from Lennox has run into this in some new Edmonton houses and was giving him advice. Will have to talk to Harry L. about it some more.
Cheers
Yuri
[this message was edited by yuri on Sun 4 May 10:23] |
| | marchvac
| "Re(9):Lennox lemon, always quitting" , posted Sun 4 May 11:37
Hey Yuri you are 100% correct. A lot of older homes in Toronto have old furnaces that are 125,000 btus with small ducts and the house is only 1000sq feet. When they are replaced by a lot of these guys (hacks) they replace them with the same btus. These guys throw them in and run. Most of these homes have had insulation added and new windows and don't require the same btus. By the way how is the weather, I had the pool open last weekend and the kids loved it.
Be careful sometimes you don't get a second chance
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| | chicapet
| "Re(10):Lennox lemon, always quitting" , posted Sun 4 May 19:03
House is 1100 sq ft plus same size basement, firnca is 80,000 btu and has square ducting coming out of furnace leading going square 90 degrees into rectangle duct
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| | marchvac
| "Re(2):Re(10):Lennox lemon, always quitting" , posted Sun 4 May 20:44
My house is 3000sq feet and has an 80,000btu not including basement. How is the furnace working. Hope you don't have any more problems.
Be careful sometimes you don't get a second chance
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| | yuri
| "Re(10):Lennox lemon, always quitting" , posted Sun 4 May 11:51
Pool? Must be nice, I'm just a poor workin class slob. LOL. Must be nice to own your own co. and be your own Boss. Would have done it yrs ago but saw all the BS my ex-boss went thru collecting $$ from the deadbeats. Weathers gettin better except for today, snowin slightly. Doin A/c startups in the afternoons. Usually after the May long weekend we are safe. Enjoy the pool.
Yuri
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| | chicapet
| "Re(7):Lennox lemon, always quitting" , posted Sat 3 May 16:33
Tech just installed a new pressure switch and tube, appears to be running fine now. Thanks to everyone for their help. I will contact marchvac if there are anymore problems
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| | chicapet
| "Re(5):Lennox lemon, always quitting" , posted Fri 2 May 19:27
Back to exhaust fan only
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| | marchvac
| "Re(6):Lennox lemon, always quitting" , posted Fri 2 May 20:41
Where in Toronto. Mabey I can help.
Be careful sometimes you don't get a second chance
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| | chicapet
| "Re(7):Lennox lemon, always quitting" , posted Fri 2 May 20:53
Lawerance and Mccowan scarborough
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| | marchvac
| "Re(8):Lennox lemon, always quitting" , posted Sat 3 May 09:55
I know the area very well I did all the hvac at Cedarbrae Mall a few years ago when they renovated. Give me a call on Monday and I will come out and see what I can do. Do you still have the manual for the furnace. 416 805 3121. Marc.
Be careful sometimes you don't get a second chance
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| | chicapet
| "Re(5):Lennox lemon, always quitting" , posted Fri 2 May 19:14
i will try that, currently not running, has rollout code error, flame also started but barely lasted a second, now only exhaust fan runs
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| ampulman
| "Re(1):Lennox lemon, always quitting" , posted Wed 30 Apr 16:10
I don't think you could afford the truck charge for Yuri. He's in Manitoba, CA (somewhere around Winnipeg or Churchill.
AM
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| | yuri
| "Re(2):Lennox lemon, always quitting" , posted Wed 30 Apr 18:51
Live in Winnipeg, have visited Churchill. Gets as cold as Churchill here, minus the polar bears. Sounds to me like you have a problem with the grounding of that furnace and board to the main power supply and possibly your house. If it is burning out igniters then it may not be grounded properly. Get the tech to check from the board to a copper water line. Should have no resistance. If not grounded properly get him to check the line to the furnace and any junction boxes etc. Lennox has a test procedure for how to test the grounding with a voltage differential from C to the neutral etc. The tech should educate himself about that and call tech support for a diagram. Those Surelight boards and all boards are ground sensitive.If it is blowing limit controls then you have an airflow problem. Dirty A/C coil, ducts too small, vents closed, too restrictive type of filter etc. The tech can do a temp rise check to check that out.
Good Luck
Yuri
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