How to Wire a Humidistat to a Thermostat
How to Wire a Humidistat to a Thermostat
(OP)
Any suggestions on connecting a humidistat to a thermostat?
Ranco J10 Humidistat to a White Rodgers Thermostat.
Thanks, Mike.
Ranco J10 Humidistat to a White Rodgers Thermostat.
Thanks, Mike.





RE: How to Wire a Humidistat to a Thermostat
RE: How to Wire a Humidistat to a Thermostat
RE: How to Wire a Humidistat to a Thermostat
What sort of equipment are you trying to control? Is it a dx unit and you're trying to achieve de-humidification? Or do you have a humidifier too? Is reheat a possibility? Do you have a separate de-humidifier?
Best to ya,
Old Dave
RE: How to Wire a Humidistat to a Thermostat
RE: How to Wire a Humidistat to a Thermostat
what do you want to accomplish?
RE: How to Wire a Humidistat to a Thermostat
RE: How to Wire a Humidistat to a Thermostat
I'm extrapolating from your description that you want to de-humidify using the latent capacity of your DX coil. This is kinda tricky because you need some sort of arbitration between the two controls. If your humidistat wants to dehumidify, it will need to run the compressor to do so. How low will you be willing to let the space temperature get? You need something in between the two that makes a decision, or else a controller specifically designed for humidity / temperature control using some sort of reheat....
Let me know if that makes sense or not. I'm in kind of a hurry at the moment, but I might be able to find a controller that you could use later in the day.
Best to ya,
Old Dave
RE: How to Wire a Humidistat to a Thermostat
I found a diagram for your humidistat. It's for a humidifier, not for de-humidification. Do you have a humidifier in the system? If so, you can follow what's in the jpg. Get your 24VAC from the RC terminal on the White-Rodgers t'stat. For the 24VAC common you'll have to go back to the control transformer unless there's a spare wire pulled down to the thermostat that you can use.
http:
Let us know how you work it out!!
Best to ya,
Old Dave
RE: How to Wire a Humidistat to a Thermostat
RE: How to Wire a Humidistat to a Thermostat
RE: How to Wire a Humidistat to a Thermostat
The one time I turned the humidistat to maximum was on another job. I'm sure the humidistat overrode the thermostat and kept the compressor going past the thermostat cut off. Don't know if that is a good thing. Seems like there should be an absolute lowest temperature allowable. That begs the question, is using the AC as a dehumdifier efficient or useful? Ultimately, isn't the whole arrangement designed for cooling?
Thanks, Mike.
RE: How to Wire a Humidistat to a Thermostat
Now that you have come out with more information on your system,I would like to offer my two cents worth!I have seen similar installations where the humidistat is meant only to limit space relative humidity to a certain value say 60%.It is not meant to turn a humidifier on as a lower limit on humidity level may not be required in a comfort air conditioning installation.In such installations the humidistat and thermostat are wired in parrallel so that either one of these can turn the reheaters on.
Adding reheat raises room temperature and brings down room relative humidity.This is certainly not an ideal control system.The reason is even after achieving the set room temperature the heater will be still on to achieve the required humidity level.This obviously means that temperature control will be on a rather 'wide' band.
RE: How to Wire a Humidistat to a Thermostat
What's a reheater?
Thanks, Mike.
RE: How to Wire a Humidistat to a Thermostat
Reheat is just a heating coil downstream of the cooling coil. With a reheat arrangement, you can use a humidity / temperature control algorithm to run the A/C compressor (taking moisture from the air) and control the reheat coil with a thermostat to maintain room temperature. It's common in commercial / institutional applications where excess humidity is a problem (you'll find reheat systems in a lot of hospital rooms).
Make sense? In other words, you do allow the cooling coil to be active more than it would just for temperature control but use the reheat coil to keep the space from becoming overcooled.
Old Dave
RE: How to Wire a Humidistat to a Thermostat