Furnace Issues

[mr2mike]

Lennox mid efficiency here.
I've got spare sensors. Anything else I should be hoarding?
Have only had to change the ignitor and flame sensors once.
I also clean it seasonally and spend too much time doing so according to @ThePenIsMightier and his "skin cell tin duct sweep method".

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How much was labor? Labor has always been the significantly cheaper part of the bill any time I've been too lazy or busy to do something myself.

Not that I call services too often but I find they bury the labour in with part cost and travel time and round up on hours. Little bit here and there.

[ZenOps]

Lennox high efficiency. 10 years but in the last few years had to clean the flame sensor twice annually. Pre-purchased spare flame sensor.

Although finicky at extremely low temps, still holding on.

[redblack]

Woke up to a cold house this morning
Circuit board flashed a code 31. Checked all the hoses to pressure switch and inducer. Ended up finding that my condensate trap was clogged. Pulled the hose off and was greeted to about a gallon of water trapped upstream of the trap.
Spent 10 minutes washing and blowing out the trap, a bunch of gross nasties came out of it.
Buttoned her up and furnace fired up again. Pretty happy I was able to fix it with minimal diagnostics.

Just some info for you guys if you ever get the same code.

[ThePenIsMightier]

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Woke up to a cold house this morning
Circuit board flashed a code 31. Checked all the hoses to pressure switch and inducer. Ended up finding that my condensate trap was clogged. Pulled the hose off and was greeted to about a gallon of water trapped upstream of the trap.
Spent 10 minutes washing and blowing out the trap, a bunch of gross nasties came out of it.
Buttoned her up and furnace fired up again. Pretty happy I was able to fix it with minimal diagnostics.

Just some info for you guys if you ever get the same code.

Do you just mean the hose and PVC piping that leads to the floor drain was clogged?
I haven't heard of a condensate trap before.

[redblack]

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Do you just mean the hose and PVC piping that leads to the floor drain was clogged?
I haven't heard of a condensate trap before.

It’s the hose circled in red. The white box is the condensate trap, this is a carrier furnace

[Darell_n]

That’s how high efficiency furnaces save energy is by not providing heat at all for a few days per winter.

[littledan]

Heat inside your home causes climate assault. You should be living in an igloo using seal fat for survival. #freenotley

[roopi]

Woke up to error code E250 open limit switch (Lennox EL296UH070XV36B-05) the other day. Power cycled furnace and it operated fine for 2 days. Getting the same error code again and won't start now. Fan turns on and I can see it ignite and then it goes into soft lock out. Flame sensor has been cleaned. Any suggestions on what to check? Can't find much online regarding this and getting a tech to take a look is a week away.

[killramos]

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Heat inside your home causes climate assault. You should be living in an igloo using seal fat for survival. #freenotley

Don’t forget to ensure you have vegan no animal cruelty seal fat you bigot. Unless you are exercising your treaty rights, in which case consult the second set of laws in this country based on your race and carry on.

[littledan]

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Woke up to error code E250 open limit switch (Lennox EL296UH070XV36B-05) the other day. Power cycled furnace and it operated fine for 2 days. Getting the same error code again and won't start now. Fan turns on and I can see it ignite and then it goes into soft lock out. Flame sensor has been cleaned. Any suggestions on what to check? Can't find much online regarding this and getting a tech to take a look is a week away.

Did you check your air intake and exhaust for ice or snow clog?

[roopi]

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Did you check your air intake and exhaust for ice or snow clog?

Yes sorry forget to mention that was also checked.

[littledan]

Do you have a fresh filter in there? could be a bad limit switch or something causing the temp rise to be too high like bad airflow.

*not an HVAC tech

[asp integra]

If its just blowing air and not heat, its probably because the furnace is overheating (happens when its -30 and literally needs to run constantly) I know because it happens at my house every year. Best thing to do is just hit the main power switch for the furnace for a few seconds then turn it on again. Have to do this every once in a while durring really cold snaps

[2020]

Open limit switch means it’s running too hot. Could be as easy as a bad switch or worse case a cracked heat exchanger $$$

[schurchill39]

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Do you have a fresh filter in there? could be a bad limit switch or something causing the temp rise to be too high like bad airflow.

*not an HVAC tech

This would happen to mine and I would take the filter out for half a day so there was no restriction at all and it would cool down a bit. Once it got back into the groove of working I'd replace the filter with a new one.

[roopi]

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Do you have a fresh filter in there? could be a bad limit switch or something causing the temp rise to be too high like bad airflow.

*not an HVAC tech

Yes I changed the filter even though the one in there was recently changed.

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If its just blowing air and not heat, its probably because the furnace is overheating (happens when its -30 and literally needs to run constantly) I know because it happens at my house every year. Best thing to do is just hit the main power switch for the furnace for a few seconds then turn it on again. Have to do this every once in a while durring really cold snaps

It doesn't get to blowing air at all. Seems like the blower doesn't start so it overheats. Main power switch worked once to get it running again but no longer works.

- - - Updated - - -

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Open limit switch means it’s running too hot. Could be as easy as a bad switch or worse case a cracked heat exchanger $$$

I've been looking online for the switch location for this model but can't seem to find much info on it. I'll keep searching.

[littledan]

Does your blower motor run at all? Can you set it to continuous run?

If your blower motor is bad your furnace won't run because it will overheat. If your inducer fan is good and gas valve is good and flame proving sensor is good then maybe its as simple as the blower??

[16hypen3sp]

I agree with littledan. Set to "FAN" or whatever to see if blower runs?

[littledan]

Quick hypothetical question on lennox high efficiency furnace. If the inducer/burner exhuast gets iced up and the furnace goes into lockout mode, does a constant tstat call for heat cause the blower fan to run continuously? Also, the eac pin in the manual says that it is 120vac when "blower fan is running" and it also says it is 120vac when there is a "call for heat, cool, or fan" . So im not sure when the control board actually turns on the eac, if its when the blower is running, if there is a call for heat, and how that applies to a lockout mode. I.e. if lockout will fan run continuosoly and eac stay live?

[R-Audi]

Seems like a lot of people have Lennox furnaces.
Recently had mine replaced and the plumber went off about them... particularly the 10-15yr old models. Went on about parts being too expensive and wondering why so many people would buy a furnace that was made in the southern US. Think Texas to be exact. He said the really old ones are excellent, but for some reason the newer generation wasnt, and every part I needed was at least a few hundred more then the competitors. Also went on about not using upgraded filters as it just causes the fan and blower to work harder.. cheapest 3 pack or whatever that home depot sells.
We ended up with a Napolean furnace.. apparently made in Canada. Only time will tell if it holds up.