Dehumidity on Demand

[Hobie5x5]

So my zoned system. The other day the HZ432 was set to command stage 2 with Timer. RH was down around 45%. Now the HZ432 is set to command stage 2 by %Zones. RH now sitting around 51%. System is running more(Stage 1 as I expected) and should be using much less electric. So to deal with the humidity, would you recommend Comfort R or DOD with the Prestige IAQ 2.0?

[beenthere]

DOD. Comfort r is a waste when the outdoor temps are at around 75% of design temp.

[Hobie5x5]

Thanks. I will have the installer set it up with DOD. Thanks

[catmanacman]

I not sure that you can use dod with the zone system

[beenthere]

I not sure that you can use dod with the zone system

Only the zone with the HD stat will DOD. But all zones will benefit from it, since all zones should have a return in them. Humidity/moisture doesn't stratify like heat does. Plus anytime the HD stat zone is in a DOD call and a cooling all from another zone as runs, the HD will keep the blower slowed.

[Hobie5x5]

so my installer is somewhat confused. U1 on the EIQ should be wired to what terminal on the HZ432? I will tell him to cut the BK jumper on the AFC and to wire BK on the Air handler to BK on HZ432. IS there any other jumpers that need to be installed?

[Hobie5x5]

Any advice?

[beenthere]

Generally don't give out wiring advice in the AOP forums.

[teddy bear]

Thanks. I will have the installer set it up with DOD. Thanks

Adjust your a/c to max out its ability to control %RH when there is a cooling load.
A healthy home should have an air fresh change in four hours to purge indoor pollutants and renew oxygen. During windy, cold weather, natural infiltration usually provides enough fresh air. During calm weather, mechanical ventilation is needed to get 60-80 cfm of fresh air when occupied.
Homes are healthy and comfortable with <50%RH which is about a 55^F dew point at 75^F. Keep in mind there are many days when the outdoor air contains more moisture than you want inside your home. Outdoor dew points are upto 80^F in green grass climates. Also two occupants add about 1 lb. of moisture per hour to air in their home.
During peak moisture loads, your a/c removes 3 lbs. of moisture per hour per ton.
When the outside temps decline below inside temps, there is no cooling load, yet the outside dew points are +60-70^F. As the infiltrating outside fresh air replaces the dry inside air, the dew point of the inside air rises to the outside dew point plus the moisture from the occupants. 1 lb. of moisture per hour added to the 60-80 cfm of 65^F dew point infiltrating air. expect a +70^F inside dew point. The a/c is not operating enough to maintain <50%RH. Yet a dehumidifier removing 2-3 lbs. of moisture per will maintain <50%RH. I am attaching a PDF showing data from a WI home a couple days last.
The mainfloor and basement are <50%RH without any a/c cooling and a dehu removing 1-2 lbs. per hour depending on the outside dew point and 12 hour/day occupancy. 80 cfm of fresh air ventilation 24/7.
Very comfortable and healthy
Regards TBWI Home dehumidifier 50RH.pdf