Question for the AC guys

[Marco]

I hear you.... Been in the AC Commercial business for over 30 years and there is something new just about everyday.

[critter69]

Ductboard is crap.

Yea I wouldn’t ever use duct board. I can’t image breathing all that fiberglass, and then the dust and dirt sticking to it, and it’s far from durable. Metal duct is the way to go. If you must insulate ( here we don’t) use the silver bubble wrap stuff around the out side of it. That way it is smooth inside and far easier to clean. And has to be soooo much healthier.

[critter69]

If you mounted your air handler horizontal, most have a defector shield you place downstream of the coil, to keep the water from getting blowen out of the drain pan, with out the need of turning your blower speed down. If you don’t have enough air across your coil you may have issues with it freezing up.Did you check your sub cooling , charge ?

[kmitchl]

Look several post up. The duct work is a 20x23” rectangle 32’ long with registers spaced toward the end. I think the issue is the duct doesn’t provide any backpressure on the blower. So the blower is way out at the end of it’s curve. Reducing the blower speed or closing the registers to back the blower up the capacity curve reduces the air velocity over the coil and condensate carryover. Charge was set with 10 degrees of subcooling.