Quote:
Originally Posted by Jarredsdad  Both. Assuming a top notch IAQ stat, the stat directs the Furnace control board to run the Furnace Fan and A/C in Cooling Mode or DEHUM Mode.
First thing the A/C works on is humidity before working on sensible temp.
When Jay had His system at 72 the unit worked so much to get to set point humidity wasn't a problem by the time the stat was satisfied.
These days, Jay's system is looking at a Cooling call and a DEHUM call. Cooling gets handled first so his system starts in cooling until that is satisfied.
When that happens and there is still a call for DEHUM the system slows the fan down (Trying not to over cool the house) with the A/C (outdoor unit) still running.
Slowing the fan down also allows the air to stay in contact with the now colder coil longer and condense more moisture faster.
Make sense? |
Yes and
thank you so much. This is a very important topic which is not well understood.
So let's see if I have this correct:
An air handler (furnace) with a veriable speed blower has two calls a thermostat can request:
* COOLING
* DEHUM (dehumidify)
Cooling request simply runs the furnace blower at full speed* (with outside condensor on) until the thermostat reaches the desired temperature. Humdity level is not considered and may be at any level when the desired temperature is reached.
Dehumidify request runs the furnace blower at a slower speed (with the outside condenser on) to freez-up the coil causing faster condensation and thus removing humidity but not cooling the house faster. The temperature may go lower than set point in order to achive correct humidity level thus the house may be colder then desired.
So a smart thermostat like the Honeywell Pro IAQ that has a humidity level control and obviously a temperature level, can make the proper call to cool or to dehumidify? When both the humidity level and temperature levels are set on the thermostat, does the thermostat always start with the humidity call first followed by the temperature call, or can these two be switched around?
*( I put an asterik above on the blower running full speed to keep it simple, but I undersand that the furnace can be set as Jay explained to ramp up at set points to help remove moisutre first, but the actual moisture level is not being considered)