New Amana HVAC Unit - Unit Runs Too Much And Too Humid?

KesslerDweller

I am the GC on a new house that we installed three Amana 16 SEER A/C variable speed units. One for the first floor (about 1,800 square feet) and two units for upstairs (about 2,200 square feet). The units have been checked out and have adequate coolant and the temp coming out of the units (not the vents but the mechanical unit) is 58 degrees

The upstairs units work great but the downstairs unit run constantly from 3 p.m. to 8 p.m. on an 85 degree day. The house is outfitted with commercial grade windows (some Western exposure) and foam insulation.

Question - am I crazy or should these units cycle on/off on a warm (not hot) day?

Is it typical for an A/C unit to run 4 hours straight or not? Seem like it to me.

The air seems humid in the house. Is there a standard humidity reading that is acceptable best practices?

I am meet with our A/C rep and engineer later this week and I want to have an unbiased opinion before they show up and tell me this is the way it is supposed to be.

Any help would be great!
Thanks!

flashheatingand

running constantly on a 85 outdoor temp day does seem like a lot. It sounds as if the downstairs unit is undersized, but it's not like we have all the facts. What is the t-stat setting? Is it possible that some ducts have fallen? You mention the temp coming out of the air handler is 58 degrees, what is the temp coming in the air handler. Living in Idaho, humidity isn't a big issue. Perhaps other a/c guys pay more attention to humidity levels, and that is a good question.

I believe, 55-60 percent humidity is what one should shoot for, but thats an "educated" guess. In summary, running constantly isn't normal on a 85 degree day unless the t-stat is set unreasonably low (25+ degrees different from the outdoor temp)

KesslerDweller

Flash - the thermostat is set at 76 to 78 during the day.

Today it got up to 95 and the thermostat was set to 77 and it ran for 5 hours straight. I will check the ducts to make sure they all are pushing air out.

Thanks!

westernhvac

I would like to know what region of the country you are in. I started working in Alabama and dealing with humidity was a big part of the design process on every home. The two speed compressors turned out to be a great system for dehumidification. It often helps to upsize the indoor coil by 1/2 ton and make sure that there is some sort of dehum control built in to the thermostat. From the runtimes and the temperature ranges it definitely sounds like something is wrong.

KesslerDweller

Thanks guys - I got the A/C guy out there to repair. Turns out the unit was not spinning down into variable speed mode. It is fixed and runs like a champ now.

Verbal

30% to 50% humidity is good. if the air is too humid, lower the fan speed one setting, its probably moving to fast over the coil to condense.



oooops nevermind, shoulda read the whole thread.