# Lennox SLP98 pressure switch issues



## becsnider (Nov 18, 2012)

Hi -

We have a two-year old SLP98 furnace that will not light. I have had HVAC techs out three days in a row (at $160/visit) and still they really don't know what is wrong with our furnace. Each time they come out, they try a bunch of different things (mostly the same things the other guy tried), read the error codes and after a bunch of trial and error, the furnace lights again and we have heat for approximately 12 hours.

After the furnace stops lighting, it keeps trying to calibrate when heat is called for by the thermostat. The inducer comes on and then the pressure switch clicks, then it keeps ramping up, the pressure switch(es) click a few more times, it keeps ramping up and then shuts down, giving error code 228.

All of the venting has been checked and is clear, all of the hoses leading into the pressure switch have been blown out and are clear. All the wiring is intact.

Seems like the furnace just happens to come back on once in a hundred or more tries by the service tech. Once they get it on, they leave and tell us to call again if it goes off. The latest senior service tech said he thought the pressure switch might be bad, so we are waiting for them to order us a new switch. Of course, they can't get one on the weekend.

Anyone else had this problem? The service tech said he thought that he remembered something about the pressure switches for this unit having a problem. Has there been a recall of them?

Thanks for all replies.

Becky Snider
Owner
Blue Dog Builders LLC


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## flashheatingand (May 3, 2008)

I did a quick internet research. I saw something about an issue with the control board, and, it could be an issue with a bad solder joint on the board. Don't want to get too technical, as this really could be a disservice. I would go to the link below, and look for a qualified Lennox dealer in your area.

I am surprised that you have to pay so much for a service call. Did you call the outfit that did the installation? 

Good luck
http://www.lennox.com/callcenter.asp


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## flashheatingand (May 3, 2008)

For those of us heater dogs, I suspect, the solder joints on the back side of the molex conector (pressure switch taps)on the board have a micro-crack. It's something to inspect when you suspect there may be a problem with the control board.


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