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Heating, Air Conditioning, Fridge, HVAC/how to get morfe condensate from AC


Hi Jim,

If I understand correctly, avg AC condensate is 0.3 - 0.5 gal/hr/ton.  I'm on the low side at 0.3 and I'd like to know if and how I can get more toward the 0.5.

I have a 3-bedroom rambler on a slab stick-built in 1953. The 1997 Carrier AC/furnace unit is in the middle of the house and the air vents run under the slab.  The compressor is on the side of the house with a 45 foot run for the 3/8 HP and 3/4 LP tubing.  The compressor is 2.5 ton and the evap coil is 3.0 ton.

Ever since the AC was installed it has cooled very well set on 72 deg F, but the inside RH is almost always around 60 in the summer.

Yesterday and today I tried changing the blower speed but only with modest results.  Outside temp was 94 deg F with RH about 50.  Thermostat was set to 72 deg F but it didn't get much below 75 and inside RH hovered around 62 percent. The low and med hi speeds both resulted in about 0.3 gal/hr/ton and hi speed about 0.27 gal/hr/ton.  On all speeds the pre coil dry temp was about 75 deg F and the post coil temp was about 55 on low speed, 57.5 on med hi speed, and 58.5 on hi speed as read about 6 - 8 inches from the coil.  The air filter was clean and everything seemed to be functioning normally -- except for the low condensate.

I've read that units after the early 90's are more energy efficient and, by default, are less condensate-efficient, but, gee wiz, I'd like to think I could get more than 0.3.

I also thought of low Freon, but post coil temps seem to be in line and, besides, it's been no different since it was new.

Is there any hope other than a new unit?

Thank you so much for your help.  I really appreciate folks like you who take the time to help others!


You really have a lot of technical questions and information, you might be better served to talk to a HVAC Mechanical Engineer?
What I know is that air conditioning on average is designed for a twenty degree temperature differential between inside and outside, some people like a little more, some like a little less.
Condensation occurs more or less from the temperature difference of the air and the coil, when the ac is working properly it takes  humidity out of the air, less humidity less condensation.  

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Jim Barnhart


Fifty + years conditioning the air.


Answer questions about , residential and commercial. Answer questions about sheet metal fabrication. Fifty years plus experience. No answers for oil equipment, No answers for kitchen appliances, No answers for laundry appliances, I don't specialize in one particular area of the HVAC area, I'm more of a General Practitioner, Limited in refrigeration/

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