Air handling unit shut down timer

[Chancelong]

I have an air handling unit that has 120 volt motor starter. The customer wants a button to press that will shut the unit off for 20 minutes then turn back on, but also once the button is pressed, the button needs to be deactivate for an hour to stop the air handler from being off for extended periods of time. What is the best way to go about this? A few time delay relays?

 

[LarryFine]

Yes, this can be done with two simple timer modules and a bit of control logic wiring.

 

[Eddie702]

If the ahu has an ac condenser or heat pump attached to it you need to make sure that shuts down as well. If The ahu has heat (like electric strip heater) they need to be shut down as well. You can't just kill the fan I guess is my point. Depends what other equipment is attached to it.

 

[qcroanoke]

If the ahu has an ac condenser or heat pump attached to it you need to make sure that shuts down as well. If The ahu has heat (like electric strip heater) they need to be shut down as well. You can't just kill the fan I guess is my point. Depends what other equipment is attached to it.

I would just break R from the secondary of the control xfmr. Through a N/C contact. Controlled by what ever you need to make and break the contact.