Furnace pressure switch error

[capttrip55]

House built 3 and 1/2 years ago with XR95 furnace installed when built. Won’t put out any heat today. Light shows 3 flashes the pauses. Manual says this is a pressure switch error. Any tips on what I can check at home before calling for service on Monday?

 

[Guzzle]

"All models are equipped with a manual resetting roll- out switch located near the burners."
No harm in trying this button.

If you can find how many inches of water column actuates the switch you can test it with a length of tubing, some fittings, and a VOM. The spec might be marked on the switch or an online parts depot may post the specs. Possibly similar switches are used in many 95% AFUE gas furnaces.

 

[capttrip55]

I’ve reset it a couple times

Condensate lines are clear. Power is getting to the switch. Don’t have a manometer to check pressure. Raining too much to try and get on roof today. Looks like I have a concentric vent where the exhaust and intake combine before exiting the roof. Any tips on how to check it for clogs if I make it to the roof?

 

[Guzzle]

Any tips on how to check it for clogs if I make it to the roof?

A visual check with a light at the other end, using a small mirror if necessary.

 

[billshack]

Condensate lines are clear?, is this a stream furnace ? hot air what ?