The air compressor and a regulator are currently hard wired and we know that’s against regulations. How could I hook up the standard kop 90 viair air compressor into the computer? It says it’s 40amp and we only have 20amp spike relays. Is there a special relay?
I’m not too sure what you mean by hooking up to the computer, but a Spike relay, which comes in the KOP, would be the appropriate device to use to control the compressor.
Will 20 amps work for the Spike relay?
Yes, put the spike on a 20 A breaker to run the compressor and you are encouraged to replace the fuse in the spike with another auto-reset breaker.
Not sure where you got 40A from. The current draw listed on the VIAIR website is 10 Amps:
http://www.viaircorp.com/OnRoad/90C.html