Will this smart switch work with a compressor pressure switch?

[Pontiac787]

Hi All,

I currently have a standard toggle switch in-line with the pressure switch on my compressor. I would like to be turn the compressor on/off from two different locations. I think the easiest way to accomplish that would be with a smart switch and a remote control. There is no neutral on the pressure switch so would a Lutron Pro switch do the trick? If so, is there anything additional needed? I've seen reference to a bridge or hub when using a no-neutral switch.

This is the switch I'm referring to - Lutron Pro Switch

Thanks!

 

[wyliesdiesels]

considering you didnt give us any info about your compressor its impossible to answer.

whats the HP rating on your compressor? standard toggle snap switches are not motor rated for more than maybe 1hp.

does your compressor have a starter or does the pressure switch the full load current of the motor?

need more info here

 

[The Cobbler]

it doesn't appear to be motor rated , other than 3 amp for a fan, and it has low wattage rating for lighting to . doubtful it will last for a heavier load . maybe if you add a relay to it

 

[LukeOresk]

You have a similar problem I had when I was looking at putting my oil furnace in my shop on a smart switch. I was able to get away with this because it’s 3/4 hp rated. With out knowing your hp it’s hard to say how and if it’s possible for you

Amazon.ca

 

[Pontiac787]

it doesn't appear to be motor rated , other than 3 amp for a fan, and it has low wattage rating for lighting to . doubtful it will last for a heavier load . maybe if you add a relay to it

The compressor has a mag starter on it and the pressure switch is acting as the relay, no? It’s been a while since I wired it but I think it is only 16 gauge wire (might be 18) going to the switch.

 

[Pontiac787]

considering you didnt give us any info about your compressor its impossible to answer.

whats the HP rating on your compressor? standard toggle snap switches are not motor rated for more than maybe 1hp.

does your compressor have a starter or does the pressure switch the full load current of the motor?

need more info here

Sorry. I was more interested in the function of this type of switch. 240v 5hp motor with a mag starter.

 

[The Cobbler]

you might be OK with a mag starter .

 

[Pontiac787]

You have a similar problem I had when I was looking at putting my oil furnace in my shop on a smart switch. I was able to get away with this because it’s 3/4 hp rated. With out knowing your hp it’s hard to say how and if it’s possible for you

Amazon.ca

I have one of those running the high bay lights in my garage. It does have a higher wattage rating than the Lutron but I think it requires a neutral.

 

[johnre]

The Lutron Pro is a dimmer, and it will not work as a motor starter - it has neither the rating for your compressor, nor is it the correct on/off function.

I solved a similar problem with my 240 V 1.5 HP dust collector system by building a wireless remote with the following key components. It is much more robust than the standard commercial remotes available from woodworking suppliers:

30 A 240 V contactor

Wireless remote

NEMA enclosure

Note that the wireless base unit can operate at either 120 V or 240 V input, and its contacts only drive the A/C starter relay, not the motor directly. It comes with two remotes, so you are covered for your application. I chose a relay that had a 240 V coil on the primary, so it's 240 V throughout the controller and the neutral isn't needed.

Here's what it all looks like finished; I wired it for NEMA 6-20 plug and receptacle - and yes, I do realize I need to wrap red tape around the incoming white 240 V supply cord wire, that's the way it was when I bought it:

 

[Walkers]

They say right on the box ‘Neutral wire Required’

 

[dave*99]

The Lutron Pro is a dimmer, and it will not work as a motor starter - it has neither the rating for your compressor, nor is it the correct on/off function.

I solved a similar problem with my 240 V 1.5 HP dust collector system by building a wireless remote with the following key components. It is much more robust than the standard commercial remotes available from woodworking suppliers:

Amazon.com

Amazon.com

Amazon.com

Note that the wireless base unit can operate at either 120 V or 240 V input, and its contacts only drive the A/C starter relay, not the motor directly. It comes with two remotes, so you are covered for your application. I chose a relay that had a 240 V coil on the primary, so it's 240 V throughout the controller and the neutral isn't needed.

Here's what it all looks like finished; I wired it for NEMA 6-20 plug and receptacle - and yes, I do realize I need to wrap red tape around the incoming white 240 V supply cord wire, that's the way it was when I bought it:

Is there an antenna sticking out of that NEMA box? Hard to tell in the photo.

 

[wyliesdiesels]

The compressor has a mag starter on it and the pressure switch is acting as the relay, no? It’s been a while since I wired it but I think it is only 16 gauge wire (might be 18) going to the switch.

Nope

The mag starter is the relay. The pressure switch is what turns the relay on and off.

Whatever switch you use will need to be rated for 240v.

The lutron is not gonna work.

 

[Pontiac787]

The Lutron Pro is a dimmer, and it will not work as a motor starter - it has neither the rating for your compressor, nor is it the correct on/off function.

I solved a similar problem with my 240 V 1.5 HP dust collector system by building a wireless remote with the following key components. It is much more robust than the standard commercial remotes available from woodworking suppliers:

Amazon.com

Amazon.com

Amazon.com

Note that the wireless base unit can operate at either 120 V or 240 V input, and its contacts only drive the A/C starter relay, not the motor directly. It comes with two remotes, so you are covered for your application. I chose a relay that had a 240 V coil on the primary, so it's 240 V throughout the controller and the neutral isn't needed.

Here's what it all looks like finished; I wired it for NEMA 6-20 plug and receptacle - and yes, I do realize I need to wrap red tape around the incoming white 240 V supply cord wire, that's the way it was when I bought it:

Thanks! I didn’t realize the switch was a dimmer. I was going by the photo that just showed the on/off buttons.

 

[fitter30]

Move it to the y wire for the thermostat. Want to kill both the indoor fan second relay if fan switch is on position wire the g wire in series

 

[johnre]

They say right on the [remote device] box ‘Neutral wire Required’

I am aware. That's because it's not switched on the neutral side, only H1, so with 240 V H1 / H2 at the input of the device it would have a switched H1 and an always-hot H2 at the output of the device.

In my case this output only drives the coil in the relay, not the motor, which is fully switched on both H1 and H2 by the relay contacts.

If that's bothersome to anyone, you could instead get a relay with a 120 V coil and bring neutral into the enclosure, so that the circuit for this device and the relay coil are operating on 120 V only.

Is there an antenna sticking out of that NEMA box? Hard to tell in the photo.

No, I tested it and it does OK for range even with that pigtail totally contained within the metal enclosure. I need to go only about 30 feet away with my remote, but that's partly through a concrete foundation wall. It advertises a 328 foot range (100 meters), so there's apparently plenty of signal even with the wire not brought out.

 

[Pontiac787]

The more I think about it the simplest method may be to just use 2 3-way toggle switches. The switches are will be less than 10’ apart on different levels with no issue running a wire between. I’m only breaking one leg of the wires running to the starter.

 

[johnre]

The more I think about it the simplest method may be to just use 2 3-way toggle switches. The switches are will be less than 10’ apart on different levels with no issue running a wire between. I’m only breaking one leg of the wires running to the starter.

The issue is that a 3-way switch function is not normally available on a 240 V motor starter switch.

There's a already a lengthy discussion thread on the type of switch needed, here:

Compressor safety, it always bears repeating

found a twist it for 10-60 minutes run time switch that could handle the amp load. I just had a thread on here, using a spring wound timer for a small compressor at the Volunteer warehouse , so the little pancake compressor to run our carton stapler can't get left on .

www.garagejournal.com

 

[Pontiac787]

Is a motor rated switch required if it is only switching power to the relay coil?

The compressor in the linked thread wasn’t running a mag starter, just a pressure switch.

 

[dave*99]

Is a motor rated switch required if it is only switching power to the relay coil?

The compressor in the linked thread wasn’t running a mag starter, just a pressure switch.

If you post a wiring diagram of your compressor and plan to wire in your switch, other folks will converge on a solution. Without that, GJ is the ultimate speculation machine.

 

[wyliesdiesels]

Is a motor rated switch required if it is only switching power to the relay coil?

The compressor in the linked thread wasn’t running a mag starter, just a pressure switch.

no but you dp need a 240v rated 3-way switch. i dont usually see those at the big box stores.

 

[Pontiac787]

Agreed. HD has them for $6 with free shipping.

 

[TRWham]

Is a motor rated switch required if it is only switching power to the relay coil?

The compressor in the linked thread wasn’t running a mag starter, just a pressure switch.

No, but it needs to be rated for the voltage, and your control wiring needs to comply with Table 430.72(B)(2) which it may not in your case unless your 16 or 18 gage wire has a separate fuse (7A for 18 and 10A for 16)..

 

[wyliesdiesels]

Agreed. HD has them for $6 with free shipping.

link to switch?

 

[Pontiac787]

This is the switch. The wiring is currently 16 gauge. I’m planning on moving up to 14 gauge when I wire the 3-way switches.