Replies

1. 
   jackofalltrades777 | Aug 23, 2017 02:07pm | #1

   When I put it on dehumidification mode the interior temp drops 2-3 degrees which is weird since supposedly the AC is not in cooling mode, just pulling out moisture.

   Interior humidity dropped from 60% to 52% in a few hours and then the temp dropped from 70F to 67F.

   On cooling mode the temp is set to 72F so it's weird the temp drops in dehumidifcation mode.

   Any ideas as to what is going on power draw wise or function wise?

   It's a Mitsubishi ductless mini (23 SEER) (2016 model)

2. Expert Member
   Dana Dorsett | Aug 23, 2017 02:46pm | #2

   There is always going to be some sensible cooling during DEHUMIDIFY mode, since the heat of vaporization is being dumped outside rather than returned to the room, the way a room dehumidifer would. Daikin's Quaternity series mini-splits are the only mini-splits that can dehumidify without cooling, due to a clever (and patented) split coil & valving on the indoor unit.

   The instantaneous power draw during DEHUMIDIFY mode is probably spelled out somewhere in the manual for the thing, but it's well under the maximum possible draw, since it has to run the blower in the head at a lower speed, and still modulate the refrigerant volumes, compressor and outdoor blower low enough to ensure that the coil doesn't ice up.

   In terms of sensible cooling efficiency (rather than instantaneous power draw) it will be lower than the advertised SEER, since the DEHUMIDIFY mode algorithm is trying to maximize the ratio of latent/sensible cooling, not the efficiency. It's still pretty efficient, but not as efficient as running it in normal cooling mode.

   Some models will still operate to the cooling setpoint in DEHUMIDIFY mode, others just run forever no matter how low the room temperature goes. The description of which way it is supposed to on YOUR unit should be in the manual.

3. 
   Jon_R | Aug 23, 2017 03:11pm | #3

   Once you get into cooler temperatures, you want to use a dehumidifier, which will increase the interior temperature.

   The best answer to "how much power" is to measure it.