Many times the furnace or airhandler can be used with different capacity condenser units.
It needs to be set according to the capacity of the condenser unit.
Most furnaces are set to run on high to cool, this may be too fast for the capacity of the air conditioner. The installer must set the speed of the furnace or airhandler to match the condenser. If he doesn't, it won't dehumidify well. He should measure the amount of static pressure in the ductwork to make sure it's set correctly. Ductwork that is too small or has problems will increase the static pressure and modify the required speed setting required by a multispeed motor. A variable speed (VS) motor will move enough air once it has be been set by the control board. A VS motor will have a shortened lifespan if used in a system with excessive static pressure.
Just slowing the blower speed down may correct the humidity problem but won't detect future problems created by undersized ductwork.
You paid someone to put it in, let them fix it. If it has ductwork issues, they can document them and you can budget to get them fixed in the near future. I
“I am for doing good to the poor, but...I think the best way of doing good to the poor, is not making them easy in poverty, but leading or driving them out of it. I observed...that the more public provisions were made for the poor, the less they provided for themselves, and of course became poorer. And, on the contrary, the less was done for them, the more they did for themselves, and became richer.”
― Benjamin Franklin
i don't get it. Ever since VS became such a high demand item I have never heard so many complaints about high humidity.
Both White Rodgers and Honywell and some stats available at HD and Lowes
have a selectable humidity level control as part of the configuration.
Ain't nobody smart enough to offer them at the time of sale?
I push the hell out of the W/R stats. And on top of that the equipment I sell has a fifteen minute dehumidy selection that slows the fan down.
Some body ain't doing their job.
I agree, hvaclover, I have a Carrier Thermidistat with seperate dehumidification and humidification set points with VS and I get terrific dehumidification. Last night it was 81 degrees F at 10PM inside my home and I fired up my heat pump in cooling mode and within 45 mins the RH dropped from 56% to 43% and sensible temp went from 81 to 73 in 4 hours. I have a selection called "super dehumidification" which slows the blower down further. I noticed last night the blower ran quite slow untill the RH was under control and then blower speed increased to tackle the sensible load.
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