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Mark Henley
Mark Henley, Journeyman Technician
Category: HVAC
Satisfied Customers: 3217
Experience:  UA Journeyman Pipefitter , HVAC, Refrigeration, DDC controls. 26 years.Commercial & residential
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I have just installed a Honeywell H46C Humidistat with my AC/Heating

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I have just installed a Honeywell H46C Humidistat with my AC/Heating system. I put the Humidistat in Series with the cooling control wire. I conected the Y wire to the Humidistat and put the second wire from the Humidistat to the Y connection on the Thermostat. I did not touch the G (fan relay) wire. Now the AC & fan work when the temp is above the set point and the humidity is above its set value. When the humidity is below its set point, the AC is off but the fan keeps running till I set the temp below the actual temp. I am tempted to move the G wire to the Y wire and therefore when either the humidity is low or the temp is low the AC and the Fan will be off. Is this a good solution?

Hi,

 

If you have an RC connection on your thermostat wire that in series with your humidistat. It accomplishes your cycle but doesn't interfere with the proper fan operation. So take the jumper off of RH and RC, run a wire form RH to one humidistat wire and put the other humidistat wire on RC. You made an enthalpy control the way you have it wired which is ideal especially if you are not home very much the only problem you have is the fan thing, so you're pretty close on it.

 

Do you have an RC and RH terminal on your stat ?

 

Thanks

 

Mark.

Customer: replied 7 years ago.

MarK,

I do not have either an RC or RH terminal on my stat. The only connections are R, C, W, Y and G. It is a non-(time) programable. Only temp setting on front along with Heat-Off-Coo, and Auto-On for the fan. My purpose in installing the Humidistat is for when we leave our Florida house duing the summer.

Hi,

 

OK, if this setup doesn't include the heating season then I would just run it in series with R and leave it at that.

 

But you have another option with the green wire, you can just run the wire that is leaving the humidifier and going to yellow on the stat and also tie it to the green wire but remove the green wire from the stat. Which is pretty close to your original intention.

 

Thanks

 

Mark.

Customer: replied 7 years ago.

Mark,

I think the second option (ie The green (Fan) and yellow (Cooling) control wires tied together and conected to one of the Humidistat wires will work and was my original approach. The second wire from the Humidistat goes to the Y connection on the Thermostat. In effect the thermostat Y connection controls both the Cooling and Fan together. I may have to do some rewiring on the few times we need heat.

 

If I put the Humidistat in the R (power) line, the Thermostat would not have power when the Humidistat is satisfied (ie Humidity less then setting).

 

Am I interpreting your input correctly?

Herm

HI,

 

Yes , either way you will need to do some rewiring for heat. If you ever decide to buy a different stat get one with RH and RC terminals and you can resolve that problem. What you want to do will work , just will take some wiring with the season with the stat you have.

 

Thanks

 

Mark.

 

 

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