Truesteam wiring question

Bubbamill

Hello,



I just bought a house that has a Rheem gas furnace equipped with a HW Truesteam humidifier. It has a manual humidistat and a simple HW thermostat. The system is wired so that the humidifer will drive the fan even when there is no call for heat. This creates drafts as the cooler circulated air runs when no heat is present. Is there a way to change this to have the humidifier only run when there is a call for heat? I don't see this option in the Truesteam manual and the references online seem to indicate that I would need a more sophisticated thermostat like a HW IAQ model.



I am familiar with wiring and all things electrical so moving some wires around would not be an issue. But I was hoping that maybe this could be achieved through the dip switches on the Truesteam? Will this system easily support what I want?



I've been turning down the humidistat to prevent the humidifier from running when there is no call for heat, but then the humidifier only runs sometimes when there is a call for heat! Thanks for any assistance.



Bob

LarryC

Add a relay to enable the Humidistat when the fan runs

Home owner here, NOT a heating proffesional.

 

Since you have a forced air system, tap the control line for the fan, to drive a small NO relay to enanble the humidistat.

Bubbamill

TrueSteam wiring

Thanks Larry, I see how that could work. I was hoping there was a way to do it with the existing hardware given the "smarts" inside the humidifier. But I guess it would be easy enough to tuck a small 24 volt relay in the system somewhere to break the humidistat circuit when the heat is not running.....

Thanks again!

Ironman

Wiring

Find the "EAC" terminal on the furnace board. Connect a 120V to 24V transformer to it and one of the "Neutral" terminals. Use the 24V side to power the manual humidistat instead of the HVAC system 24V. Set dip switch 4 in the TrueSteam down.



You'll get less humidity this way, but the humidifier won't come on unless the blower is running.



If you connect the 120V side of the transformer to the "HUM" terminal, the humidifier will only run during a heating call. Again, less humidity.



Doing either of these is really defeating the purpose of the steam humidifier. You would be the same as a standard humidifier.