Should I Call For Service?

PipeGuy

I have a Whirlpool (Heil / Quaker) "high efficiency" gas furnace rated at 100K BTU/HR. The model is NUGK100AH01. It's the kind that exhausts out the side of the house through a 1-1/2" or 2" PVC-40 pipe. It keeps the house warm just fine, even on very cold days. This time of year I always see steam coming out of the exhaust. It also constantly discharges water into a floor drain. Lately I've noticed that the thing inside the front of the furnace that looks like a turbo-charger is cycling on and off - even when the blower runs continually. Does this neccesarily indicate a need for service? Burners are good and blue and there's never any ignition problem.

HVAC Doc

Check out side and make sure you do not have a build of ice that might be causing it to trip the pressure switch off then back on again. Has it been extremely windy where you might also be getting a good gust of wind down the pipe tripping the switch as well?

PipeGuy

Thanks Doc - I'll take your advice. The exhaust pipe comes out of the wall, sweeps horizontal (along the siding) and then terminates with a 90 down. There's a screen over the end. Maybe something got in there? I'll look.
Don't think wind has been too much an issue though I may have noticed it more the other day when it was gusty. I'll be more conscious of the outside conditions when I hear it cycling. Thanks again. If it keeps it up I'll be sure to
CALL A PRO.

PipeGuy

Hey, I just thought of something else. There's some kind of funky looking PVC-40 type of canister assembly down on the floor alongside the furnace. It has various small pipes and tubing running in and out of it and ultimately goes to the floor drain. Does that thing require servicing? I've never touched it.

HVAC Doc

That is your condensate pump. You might pop the top off and make sure no mold or goop is growing in it. Normally, those do not hamper a furnace from operating unless the dump straight outside and the outlet is frozen