Himidifier and Zone Control

[hart2hart]

I have a Honeywell whole house humidifier that is part of a two zone HVAC system. The humidifier is controlled by a Vanstar thermostat with humidity control option. It signals the humidifier and turns on the HVAC fan as required for Zone 1. In order to have fan in zone 2 be "on" (damper open to both zones), I installed a relay hooked to an IOLinc that detects when the humidifer is called for so IOLinc sends singal to ISY program that sets fan to "ON" or "Auto" on zone 2s thermostat. Is that clear as mud?

 

The issue I noticed is that as the humidity nears the set point the humidifier cycles off and on in 3 or 4 minutes cycles and hence so does the HVAC fan. So to prevent short cycling, I changed the simple program that controls the fan to include a 20 minute wait before it sets Fan Mode to "Auto". Thoughts or suggestions?

 

Thanks

 

 

If

Status 'Crawl Space / Crawl Space:Humidifier Sensor' is On

 

Then

Set 'Master Suite / Master Bedroom:Thermostat' Fan On

 

Else

Wait 20 minutes

Set 'Master Suite / Master Bedroom:Thermostat' Fan Auto

[TJF1960]

So if I understand correctly, then based on your program the only time the tstat fan will switch back to Auto is 20 minutes after the Sensor is Off. If the sensor is cycling every 4-5 minutes for the next 6 hours then the tstat fan will not shut off for approx. 6 hours. If that is what you had in mind I think it should work perfectly.