Automating a manual Humidistat with this relay? thoughts

I've got a manual humidistat that has percentage humidity and has low voltage power when the hvac is running.

I'm thinking of using this Remotec Zwave Fixture Switch Module so that I can automate based on current humidity and outside temperature.

New to this so wondering your thoughts on this approach. I will have to run 120 power to it, but that is not a problem for the location I'm looking at, and this will still provide the low voltage switching required to go to my hvac humidifier. I think. Thoughts?

I am assuming you are going to connect the dry contacts of the remotec in parallel with the humidistat?
What are you using to monitor humidity and outside temp?

I was going to use in parallel, but then was thinking I can just loose the humidistat altogether.
This switch module would turn on/off automatically based on zwave humidity sensors (yet to purchase) averaged around the house. For now outside temp would be supplied by an external provider (until/unless) I get my own weather station.

Since my humidistat is two wire, I would assume I would just put those two wires on the low voltage contacts.

That's correct. Connect the 2 existing wires to the dry contacts of the remotec.

Thanks. I just needed another set of eyes on my solution before I ordered and/or blew up my hvac :slight_smile:

The remotec seems a bit overpriced. The zooz zen16 has 3 contacts and costs about half of that. I believe it would do the same thing??

Is your HVAC system controlled by hubitat also? How will it know to "engage" only when the blower is running?

I've been wanting to do something with my system also...It's on the todo list.

The HVAC is not controlled by hubitat. But the HVAC signals when to engage. The humidistat (or this switch) would decide if conditions are right to turn on humidifier.

So it would not run if blower is not on, even if the zwave switch is on.
And it will not run if blower is on but my humidity sensors says not to run (controlling this switch).

The zen 16 is $55 on amazon.CA, and I'm consused on how to wire since I only have two wires connecting to my humidistat. My suggested solution I understand the wiring.

Thanks for the info. I'm afraid to mess with mine...Could you take some before and after photos of the process when you do it? :grinning:

Also, this app is very handy. I use the value for a rule that runs a stand alone humidifier in my guitar room in the winter.

Ya, I'm afraid to mess with mine, but I really want to! :slight_smile:

Pics won't be exciting, but yes I'll document it with pics.

Thanks for the Humidity Calculator link. I'll check it out. See if its valid for our cold Canadian winters. :slight_smile: :cold_face:

I think I was making this overly complicated in my head....It drove me crazy last winter having a "smart house" and yet having to go downstairs and adjust this thing everyday.

This is what mine looks like.

So i should be able to just put a dry contact relay here correct?

In the summer I could just leave the dial in the "off"position, and then in the winter I would turn it to "max" and then let my contact relay decide when to "engage"

Sorry I know I'm basically repeating what you posted, I just thought it was going to be way more involved than this.

Just reading this thread and thinking. I would be inclined to put the current manual/mechanical humistat in series with the Z-Wave controlled relay. Then set the mechanical to a %age that is just above what you would ever want.
This way if the Z-Wave goes off the reservation, the mechanical thermostat will stop the humidity from going really high.

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Yup, that sounds like a good backup just in case. I like it.

For most whole house humidifiers there is an even easier solution. Just plug the whole house thermostat into a zwave outlet. Then set the unit to 'aways on, or maximum humidity'.

That's what I did. I live in an ultra-humid coastal area, so the dehumidifier is likely to be running most of the time. I did want to be able to adjust the setting based on outside temps which are volatile --varying 30-40 degrees F all winter.

Using an old chart from Aprilaire, I set a global variable on a dashboard tile for the 'Forecast Outside Temp' then RM sets the humidity range on-off targets for the outlet.

The house is large and the dehumidifier struggles to keep up since most days are humid, even in winter, so I din't feel it necessary to add the complexity of pulling weather data and calculating indoor humidity settings on-the-fly. Though I do have @dylan.c 's post in my bookmarks and gave it serious consideration

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