Compressor remote control and "standby"

So I just picked up a used quincy qt5 and managed to get some help moving it into the basement. My existing compressor is plumbed in in a corner, a 20 gallon harbor freight unit which has honestly been great.

Anyway I have the compressor plumbed to the garage and some accessible ports on my basement shop. About half of the air I use is outside and going up and down stairs is annoying, so it's the compressor kicking in in the middle of the night with 2 (soon to be 3) kids sleeping.

The compressor is a 5 🐎 with starter, but no off button. It was made to run in a factor ask the time and based on the hour counter I picked up with it that had 21429 hours on it, this is what it did...

I'm thinking that Id like the ability to start it from the garage, and perhaps have a 2 hour timeout or something on it cause I forget to turn my current one off half of the time. Maybe a remote tank pressure reading as well.

While we're at it, if like to be able to put out in a standby mode where the output is disabled so it doesn't drain down overnight. Probably some solenoid valve on the output, maybe with another switch.

Is there anything handy or there that may do this? Otherwise I could look into some arduino based thing. If I diy, are there some good low power options that won't be a substantial psu to run? The solenoids I have find are all quite power hungry at 20 or so watts.

At the moment I'm mostly concerned about interrupting the fill cycle and bypassing the unloader.

I have that same compressor on a dedicated breaker. Breaker off to shut it down. You can probably run 120 volt? wires from the contactor coil circuit out to a remote wall light switch. Use a twist on timer switch. I have been planing to do that for ten years or so.
Or use some sort of remote computerized remote wall switch at the compressor. I remember x10 switches.
Bill D

I have a smaller compressor connected to an inexpensive wifi plug that supports google home. I just say 'OK google turn on compressor for 1 hour' to my phone and it turns it on for an hour. In your case I would use the plug or switch to control a contactor with a 120V coil. I like the idea of the solenoid valve if that would alleviate the need to turn off the compressor but I don't have any experience with that.

I suspect that the existing starter is the bigger conundrum here. Killing the power with a contactor is easy, but that starter can get in the way of turning it back on remotely unless the starter itself can be used as a contactor. So that's one thing to investigate...the capabilities of the existing starter and, perhaps, replacing it with one that can be remotely controlled.

Thanks guys, I took a look at the control circuit, and I do like the wifi plug suggestion above. I could probably have a wifi plug control a relay in the pressure switch loop the control loop is low power so it should be OK. I considered this on my existing compressor but didn't get around to implementing it as I would have to switch the whole motor in that case.

I picked up a 30A safety switch for now, but I'm not certain if I'm going to keep it or get a beefier one as it's only listed as 3hp. The 7.5 listed one was not available.

This compressor has no neutral so everything is 240V.

How big of a concern is it switching it off without triggering the unloader if it isn't done frequently? I imagine it is a similar case with the switch as switching it while off should pose no problems.

Switching off under load is no problem. The problem is trying to restart if the head is still under pressure. The motor will overload before it spins at 125PSI. Do you have pressure gauge on the cylinder head? How long does it take to leak down. You could always add a solenoid head pressure dump valve that opens when power is lost. Maybe convert a automatic drain valve. Mine, and many more, Home ac pumps have a delay circuit. When power is applied they wait a minute or two to make sure the compressor pressure has equalized on the intake and output side. Simpler design then measuring pressure.
Bill D
Bill D

No gauge on the compressor had at the moment. There's a PRV that I suppose could be used for manual unloading but it's buried under the top plate. Also a PRV between stages but I would guess this doesn't help as much.

I guess I should finish getting it wired up and see how much of a problem this will be in reality. Starting with a 30a breaker on the circuit it will probably kick off before the starter gets to have a say.