# Lennox Don't Work In The Cold



## bwilson4web (Mar 4, 2019)

With temperatures below 10 F (-12 C), the house heater, a high efficiency Lennox SLP98UH110XV60C stopped working around 10 AM. Calls to the local Lennox dealers revealed they are booked up until after Christmas. A grim Christmas future.

The installation manual was with the unit and I soon found the error code, E228 meant the pressure sensor indicates a blocked flue or air intake pipe:









Since our pine trees have been shedding needles, I got on the roof but no problem found:








I have a fear of heights and did this solo.

The pressure sensor was failing. YouTube videos confirmed the diagnosis.









Using a jumper, the failure occurs during the "calibration" startup:

Calibration starts - pressure switch OPEN
Combustion and flue fan starts a stepped speed up - pressure switch eventually CLOSE during speed steps. So I applied a jumper to substitute for the failing switch
Flue fan backs off to initial speed - pressure switch OPEN, remove jumper
Flue fan speeds up to the step when jumper installed
Furnace continues to operate adding ~8 F per hour. The TV room measured 40 F at 8:00 PM and now shows 65 F at 11:30 PM and heater is still running.










At this lower fan speed, the heating is reduced. This allows the furnace to operate just a little faster than the heat loss from the outside cold. I've set the thermostat to a high temperature to extend the house warming. So far, it is working. But eventually the furnace will warm up the house enough to turn off heating.

After a time delay, the calibration cycle will restart but fail because of the static jumper. Calibration must start with the switch OPEN and then close during the combustion fan speed step. Disconnect when the fan goes to idle and back ON when it steps up.

*LATER THAT NIGHT*

At 5:30 AM, we just had a power outage. The automatic emergency generator came on 30-45 seconds later and I restarted the furnace.









Lights, power, and heat …. neat.

Bob Wilson


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## SalisburySam (Jun 6, 2018)

@bwilson4web good on you for the diagnosis and jerry-rigged solution to overcome the issue (no heat in home). And those whole house generators are really nice to have when/if you need it. Hope you can get a more permanent solution from Lennox soon. BTW, love the sink and counter standing on its side next to the ladder. Has to be an interesting story there as well.


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## bwilson4web (Mar 4, 2019)

SalisburySam said:


> the sink and counter


Wife frequented surplus stores and decided it would a perfect replacement for the existing, bathroom counter. She got it for $75 and then let me know I had to pick it up.

The wood cabinet and drawers are in the house but the counter and sink are 'water proof.'

Bob Wilson


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## android04 (Sep 20, 2017)

bwilson4web said:


> With temperatures below 10 F (-12 C), the house heater, a high efficiency Lennox SLP98UH110XV60C stopped working around 10 AM. Calls to the local Lennox dealers revealed they are booked up until after Christmas. A grim Christmas future.
> 
> The installation manual was with the unit and I soon found the error code, E228 meant the pressure sensor indicates a blocked flue or air intake pipe:
> 
> ...


If you are comfortable doing it (looks like you probably are), you can get the part # from the pressure switch and just go buy it from any local Lennox dealer that has it to install it yourself. Good job on the diagnosis and workaround. Good thing the combustion fan didn't go out because those are expensive ($1000).


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## bwilson4web (Mar 4, 2019)

I will try to get the replacement part early next week as a health and safety feature. It looks to be fairly straight forward. Then I'll schedule a complete furnace inspection and re-work when the Spring weather returns. 

Bob Wilson


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## JasonF (Oct 26, 2018)

That pressure switch is a _very_ common commodity part. You can probably get it from any appliance/HVAC parts supply outlet.

In the mean time, bypassing that switch is safe if you determined that there is no blockage. But remember the blockage might be in the vent fan or inside the cabinet, so it also would be smart to make sure your CO detector is working. Those are so sensitive that as long as it's not going off, you'll be perfectly safe until you can get the part.


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## bwilson4web (Mar 4, 2019)

JasonF said:


> That pressure switch is a _very_ common commodity part. You can probably get it from any appliance/HVAC parts supply outlet. . . .


On Christmas Eve I ordered a 'rebuild' kit, $75. I have no delivery expectations given the season. Regardless, I hope to have it working in a week. BTW, I went on the roof already and the pipes are clear.

Bob Wilson


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## JasonF (Oct 26, 2018)

bwilson4web said:


> On Christmas Eve I ordered a 'rebuild' kit, $75. I have no delivery expectations given the season. Regardless, I hope to have it working in a week. BTW, I went on the roof already and the pipes are clear.


I don't doubt that, but there is an inducer motor (basically a blower that pushes air out through the vent) and that can get clogged inside the blower wheel.


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## NR4P (Jul 14, 2018)

JasonF said:


> That pressure switch is a _very_ common commodity part. You can probably get it from any appliance/HVAC parts supply outlet.
> 
> In the mean time, bypassing that switch is safe if you determined that there is no blockage. But remember the blockage might be in the vent fan or inside the cabinet, *so it also would be smart to make sure your CO detector is working. * Those are so sensitive that as long as it's not going off, you'll be perfectly safe until you can get the part.


 This is THE best advice. Every home needs one or more. With a furnace and whole home generator, there is always a possibility of a CO leak into the house. These detectors are not expensive, last about 6 years and rarely false alarm. Look for the dates on your CO detector. I replace mine every 6 years when they alert me.

When they alarm, you leave the home and call 911. Do not try to reset them.


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## bwilson4web (Mar 4, 2019)

I created this YouTube to detail the furnace workaround:





Bob Wilson


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## danstockelman (7 mo ago)

android04 said:


> If you are comfortable doing it (looks like you probably are), you can get the part # from the pressure switch and just go buy it from any local Lennox dealer that has it to install it yourself. Good job on the diagnosis and workaround. Good thing the combustion fan didn't go out because those are expensive ($1000).


Service Expert shops are also Lennox and should have, or be able to get, parts.


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