Hello,
I have Aprilaire 600 with Model 60 humdistat installed. Would like to add a Suncourt motorized damper (ZC106 Zone Master Motorized Zone Control Damper). I currently have the humidistat set-up to run humidifier with heat call only. I am not using a transformer, powering off of 24VAC HUM furnace terminal.
FurnaceHumidistat
RR
CC
WW
HUMH
COMMONsolenoid
H from humidistat to solenoid

Can I just attach the each wire from the damper to the each wire of the solenoid so that the damper opens when humidistat is calling for humidification?

Thanks for any assistance you can offer.

 

Yes, you could wire the damper onto the wire that feeds the solenoid. Make sure the damper is 24 volts.

Also, why are you adding the damper?

 

Thanks for the information. The damper and the humidifier are both 24v. Using the 24v HUM terminal off my Lennox G51.
Adding the damper for efficiency. Doesn't seem like a good use of heated air to be flowing through the humidifier if it is not in operation and has already reached/maintaining set humidity level. To me seems silly to heat air to then just bypass it through the return if the humidifier is currently not calling for water/humidification.

Was looking at the Suncourt ZC106. Any information/feedback you could offer? It seems to be a value priced product in comparison to others I have seen. Figure it won't be getting major use, only during heating season (OH) and house seems to maintain humidity level well.

Thanks again.

 

Personally I would use a separate transformer for the humidifier circuit instead of the furnace transformer. The reason for the separate transformer would be to lower the load on the furnace circuit and to keep a failure in the humidifier circuit from keeping your furnace from running. The damper would need to be closed with power off.

 

7474 - Thanks for the idea. I purchased a Honeywell TrueSteam humidifier because the application efficiency of a bypass humidifier didn't sit well with me... especially with a new state of the art, variable speed, modulating, super efficient, communicating... blah blah blah HVAC system. Long story short, the TrueSteam won't work properly with my communicating system and on top of that I read it's junk anyways, so I'm scrapping it. Anyways, I like your idea and will be implementing it with my bypass humidifier.

 

No problem. As I said earlier, just figured like a waste of conditioned air when the humdifier wasn't operating. I found myself frequently going down to check the humidistat and manually closing the damper. Thought there had to be a better way. In theory seems like it will work perfectly, have to see when I put it into practice.

 

Thanks for the information. My numbers for this thought process are as follows. Please correct me if I am wrong or with any additional insight.

From my furnace literature....
40VA transformer with a 120V primary and 24V secondary
24V circuit breaker rated at 3A at 32V

So, if my numbers/calculations are correct...
Humidifier .5A at 24V = 12VA
Damper .25A at 24V = 6VA
18 VA total, .75A total = below 40VA furnace transformer and 3A circuit breaker
According to Aprilaire rep, the humdistat is capable of handling 22-30 volts.

Thanks again for taking the time to answer my question.

 

Similarly speaking, I was thinking of using a normally open damper on my bathroom HVAC register that would close when I turn on the exhaust fan. I can just visualize the conditioned air coming out of the register and going straight out the exhaust fan.

 

Yes, the transformer should be enough to handle the added load. The circuit also contains the loads of the controls in the furnace that you did not account for. My point though was if the damper motor or solenoid shorted on the humidifier that if you wired it using the furnace 24V circuit that it would also cause your furnace to not run due to the breaker being tripped and both the furnace and the humidifier on the same circuit.

 

Wow seams like a lot of work for 100 cfm of air. BTW the air is not being wasted it's just not going past the heat exchanger not a big deal with a furnace.

 

 

Thanks again for your assistance.
I understand your point regarding the humdistat causing the furnace breaker to kick off.
I am trying to keep the wiring as simple as possible. My expertise is in anything but HVAC and wiring. Figured if the damper could be connected with the solenoid that would be easy enough for me. If you could make it close to idiot proof for me to use the transformer on the damper with it opening on call for humidification I would be all for doing things your way.
Thanks again for taking the time to help me with my question.

 

Does a 6" duct only take off 100 CFM? Didn't know it was that little.

The air is not being wasted but the energy to heat the air is being wasted. The conditioned air never reaches the rooms it is meant to heat. The hot supply air is mixed with the warm/cool return air. In my eyes seems like a waste of heated air if the humidifier isn't calling.

Thanks for the insight into it only being 100 CFM, like you said might be more work than it is worth.

 

 

Thanks a lot for the wiring diagram. You speak my level of idiot proof...pictures. Even went the extra mile for the G51 control board, nice.

Thanks again your assistance is greatly appreciated.

 

hvactechfw - Do you happen to have the control board diagram for a Trane XC95M?

 

what do you need from it?

 

I didn't see any HUM terminals on mine. I'm looking to do the same thing as 7474.

 

your HUM-H 120v HOT wire is prerun to the junction box in the furnace where your 120V power comes in from the house electrical. The wire is lableled on the wire and it has a cap on it. There is also another wire that is capped off and it is labeled EAC.

 

Found them, thanks. My XL950 stat has the option to humidify with or without call for heat. I assume the 120v HUM wire becomes hot only when the stat calls for humidity?

Also, my blower runs at 40% when there is no call for heat (could be wrong about that %). If I set the XL950 to humidify even when there is no call for heat, will it increase my blower speed during this condition?

 

Set it to humidity only during heating.