Odd problem with Luxaire (York) gas furnace.

stretch5881

Luxaire 98% modulating gas furnace installed in 2010. I get an intermittent code for "pressure switch closed", 2 red flashes. This only happens when the temp outside drops below 0. I have found that a bead of condensation blocks the hose to the lower pressure switch. I blow the water out of the hose and then it runs fine. When it's that cold out, I need to run the furnace with the front cover off to prevent the condensation. The hose in question is the square hose with the curl in it.

EBEBRATT-Ed

@stretch5881

That's good troubleshooting, not sure what the fix is. Somehow you have to keep water out of that tube

Ironman

It sounds like you may be getting some flue gas recirculating into the fresh air intake. Can you post some pics of the vent termination and piping?

stretch5881

stretch5881

In the first pic, the pipe on the left is the exhaust.
In the second pic, the pipe on the left is the intake.

stretch5881

Ironman said:

It sounds like you may be getting some flue gas recirculating into the fresh air intake. Can you post some pics of the vent termination and piping?

Thinking about it even further, the wind was out of the west at over 10mph yesterday and this morning when it coded.

Ironman

That actually looks pretty good. Some manufacturers are now recommending using a 45* Ell on the top of the exhaust termination, instead of a 90* Ell blowing straight out. There's less chance of exhaust gas recirculation with the 45.

I'd also see if you can get the pressure switch hose to have an upward curve in it (inverted trap) to help prevent moisture from going into it.

stretch5881

I'll try the upward curve and see what happens.

stretch5881

All good this morning, but may take a week or two to see the result.

HVACNUT

If it happens again, try removing all hoses. Clear them out and the bung holes they attach to. Also check/ clear the main drain, trap, condensate pump, etc.
I could be just periodic.
Combustion is not 100%. The little Gremlins find a way to haunt you.
I have to do it at my out-laws house every other year. And theirs is concentric out the roof.

stretch5881

Will do, thanks.

Henry

I have a York that had a similar problem. I modified the hoses to prevent any kinks. 6 months later, York had a recall as the hoses were too long.

stretch5881

Since following ironmans' suggestion on the upward curve of the hose, there have been no hiccups. It's running better than it ever has since installed 10 years ago.