Compressor Pressure Switch w/ time delay (to use with a dryer)?

[Stroonzo]

I have a decent air compressor that serves my needs just fine. I am considering buying the Harbor Freight Air Dryer and adding it on.

According to the user manual of the HF Dryer, one must turn the dryer on and let it run for a bit to build up pressure, then start the compressor. Once the compressor cycles off, you’re supposed to then shut down the dryer.

My friend has a completely pro air setup and from looking at his I am curious if there is some sort of cost effective way to add a controller / pressure switch.

What I imagine is the following:

Air pressure is low, pressure switch activates to start up the dryer, dryer runs for 30 sec, compressor starts, pressure switch deactivates, compressor stops, dryer runs for 30 sec, dryer shuts off.

Replacing the pressure switch with a unit already designed to accommodate this would be ideal (if there such a thing). If not, and if nothing exists that is on the frugal side (I guess I could spend a lot of money on a real controller), I have been wondering about maybe repurposing an HVAC controller in an attempt to make my own dryer controller.

Any thoughts?

 

[dmoore]

It isn't that you want to start the air dryer early it is that you want to delay the start of the motor. So you end up with:

Low Pressure SW closes > Power to > Air Dryer & Motor Starter Relay > Air dryer starts right away > Motor Starter Relay starts 30 seconds later > Lower pressure switch opens > both relays off

http://ecmweb.com/training/basics-time-delay-relays