Need help wiring in new Humidifier

[dgold]

Hello all,
I am installing a new whole-house humifier and am looking to do so in a way where two conditions must be met for the humidifier to turn on:

The fan on the air handler is running
The humidistat is closed (ie, provides electrical continuity)

Please see the two pictures below:
One shows the basic layout of my York air handler including the existing humidstat mounted on the return duct, the old (to be removed) steam humidifier, and the new humidifier.

The new humidifier has the option of being triggered by either 24vac or by simple continuity across the wires intended to be hooked up to a mechanical humidistat. However both pairs are not to be hooked up.

My thought is to use the 24vac trigger, but then to run the 24vac in series, sending the hot to the humidistat, and then to the humidifier. Hopefully this makes sense. This board has been an invaluable resource over the last few years, hopefully someone can guide me.

Thanks in advance,
David

[Chris75]

You can use a sail switch or a current sensing relay in series with your humidistat to turn on the humidifier.

http://www.ntsupply.com/images/products/50_relay_lg.300x184.gif

http://www.ntsupply.com/images/products/50Closeup100.300x225.gif

Current sensing switch made by Aprilaire by the way...


So what I would do is come off "W" terminal hit the current sensing relay, then hit the humidistat, then the humidifier. and bring a common from the transformer to the humidifier.

[nhmaster]

I usually wire the humidistat in paralell so that when the air handler runs the thermostat controlls the humidifyer. No point in complicating it.

[Chris75]

I usually wire the humidistat in paralell so that when the air handler runs the thermostat controlls the humidifyer. No point in complicating it.

Depends on the setup, sometimes you would not want the humidifier running without the fan on.

[dgold]

Never heard of a current sensing relay before. That should work just great! This community never fails. Thanks again!