Anyone use a motion detecting switch to control air compressor?

[healing]

I want to avoid the air compressor running all night in case of a air line plumbing break by using a motion sensing switch that only allows current to the compressor if the shop is occupied. The motion sensing switch will switch a relay so current rating will not be an issue. I see they have adjustable programming from 5 minutes up to 2 hours. Are these motion sensing switches reliable?

I know I could just turn the compressor of when I leave but I would forget about it half the time. Thanks

 

[mayday0017]

Thought about doing the same thing, I just got in the habbit of turning the ball valve to the lines each time before I go in. Depending on what compressor you have you can do what you are wanting for as little as $5-10.

 

[icenfire01]

This seems like a GREAT idea. I always forget to switch off the compressor and was thinking of making a dedicated outlet to the light switch but this would be much simpler. I have used this type of switch in a laundry room before and it worked great.

 

[Davefr]

The only problem I see is if the relay happens to shut off power while the compressor is running. (maybe it didn't detect motion and timed out).

If that happens, upon restart the compressor will not have had the benefit of having head pressure bled down from the unloader valve which is triggered directly from the pressure switch. If the pressure switch doesn't toggle to off then the unloader valve on most compressors doesn't actuate to bleed off head pressure.

That could result in a failed start when motion is again detected. (possibly damaging the motor if it can't start due to excessive pressure). That could result in dangerous situation.

 

[JakeKohl]

The only problem I see is if the relay happens to shut off power while the compressor is running. (maybe it didn't detect motion and timed out).

If that happens, upon restart the compressor will not have had the benefit of having head pressure bled down from the unloader valve which is triggered directly from the pressure switch. If the pressure switch doesn't toggle to off then the unloader valve on most compressors doesn't actuate to bleed off head pressure.

That could result in a failed start when motion is again detected. (possibly damaging the motor if it can't start due to excessive pressure). That could result in dangerous situation.

I thought that the pressure switch would automatically relieve the pressure if the compressor was not energized? I'll unplug mine tonight and give it a whirl. I like the idea of a relay off the lights tho...I'll probably add that to my to-do list when I rewire my little/old shop that I enter my new shop through.

 

[Davefr]

I thought that the pressure switch would automatically relieve the pressure if the compressor was not energized? .

I don't think so (at least on mine). The pressure switch only actuates the unloader valve when the pressure switch breaks contact upon tank pressure reaching the cutout setting. (all mechanical based on pressure).

If tank cutout pressure hasn't been reached the unloader valve stays closed whether or not there's incoming power.

 

[readhead]

Mine works the same way. I would be concerned about breakage on restart.

 

[Playwme]

Do you turn the lights off when you leave? Hook a relay to the light circuit so that if lights are on, compressors on.

 

[Ross/Kzoo]

You are talking about less than 15 Amps on a 110 Volt circuit, right?

 

[paranoid56]

mine unloads anytime i flip the switch to off, infact the past 3 or 4 i have had all have done that.

 

[b-body-bob]

Yeah it'd be worthwhile to figure out what kind of unloader your compressor has. Both mine have centrifugal set ups so when the pump stops turning, the pressure is unloaded.

 

[Davefr]

mine unloads anytime i flip the switch to off, infact the past 3 or 4 i have had all have done that.

Yes, but if the motion detection circuit cuts power going to the compressor, the switch will still be on.

Yeah it'd be worthwhile to figure out what kind of unloader your compressor has.

^^^That's the right answer!!

 

[healing]

Both the saylor beall and the gardner denver unloaded when I pull the plug during a cycle. So it looks like in my case it will not be a problem.

 

[Ross/Kzoo]

Nobody has answered the question if the motion detector switch can handle the ampacity needed for the motor load. I don't think so for most compressors it's a moot point

 

[taumac]

The lighting idea works but what about fixing air leaks so compressor doesn't leak or run.

The 5 Stitches Garage part 1 http://www.garagejournal.com/forum/showthread.php?t=142100

The 5 Stitches Garage part2 http://www.garagejournal.com/forum/showthread.php?t=211899

 

[vhol5]

I want to avoid the air compressor running all night in case of a air line plumbing break by using a motion sensing switch that only allows current to the compressor if the shop is occupied. The motion sensing switch will switch a relay so current rating will not be an issue. I see they have adjustable programming from 5 minutes up to 2 hours. Are these motion sensing switches reliable?

I know I could just turn the compressor of when I leave but I would forget about it half the time. Thanks


Nobody has answered the question if the motion detector switch can handle the ampacity needed for the motor load. I don't think so for most compressors it's a moot point


I guess you missed that...

 

[er3456df]

Nobody has answered the question if the motion detector switch can handle the ampacity needed for the motor load. I don't think so for most compressors it's a moot point

HVAC contactors are cheap. Can get one with 120vac coil.

 

[Ross/Kzoo]

Yes, I did miss it. I've had a motion sensing switch for my shop lighting for about 15 years. It's about 99.99% effective. For some odd reason that .01% of the time it stays on and resets itself to a different mode. That's probably been about 5-10 times in the last 15 years.

 

[Regnar]

The only problem I see is if the relay happens to shut off power while the compressor is running. (maybe it didn't detect motion and timed out).

If that happens, upon restart the compressor will not have had the benefit of having head pressure bled down from the unloader valve which is triggered directly from the pressure switch. If the pressure switch doesn't toggle to off then the unloader valve on most compressors doesn't actuate to bleed off head pressure.

That could result in a failed start when motion is again detected. (possibly damaging the motor if it can't start due to excessive pressure). That could result in dangerous situation.

You could also wire the Relay to operate like a 3 way switch by running a wire from the pressure switch on the compressor. If the pressure switch on the compressor is energized then the relay/contactor coil is energized. Once pressure is meet the coil would de-energize until motion is detected again.

:This is assuming the pressure switch is 120v!

 

[b-body-bob]

^ that's using the old noggin

 

[b-body-bob]

The lighting idea works but what about fixing air leaks so compressor doesn't leak or run.

Fixing the leaks is just S.O.P. but the motion detector would prevent the compressor from running constantly due to some failure - like the time I had a HF filter/dryer blow apart. I don't know how long it had been running when I finally noticed it, but it was long enough the insulation paper (no sheetrock) right at the leak looked burned.

I learned at that time to ALWAYS turn it off, and the lesson stuck. Taking that to heart like I did gives me the same net result as the OP is looking for out of the motion detector setup.

 

[waggie]

it will probably take some programming, but, yes, it can be done. I used to install home alarm systems, which are, basically, just relays -- to the siren speaker and phone call to your monitoring station.

a better way would be to set up the relay to shut off your main air valve. that way, if your pipe burst, or leak, your compressor is still pressurized (assuming the main valve doesn't leak) and won't run at all.

 

[Regnar]

What would need programming? I thought we were talking about one of these
http://www.amazon.com/dp/B0007N72PG/?tag=atomicindus08-20

paired with one of these

http://www.amazon.com/dp/B001KGSJ74/?tag=atomicindus08-20

 

[Spinaker01]

Nobody has answered the question if the motion detector switch can handle the ampacity needed for the motor load. I don't think so for most compressors it's a moot point

It would need to be connected through a relay or contactor...

 

[bazzateer]

Or just plug the compressor in using a timer set to supply no power at night?

http://www.amazon.co.uk/s/?ie=UTF8&...vptwo=&hvqmt=b&hvdev=c&ref=pd_sl_1k5o6b70ah_b

 

[taumac]

Fixing the leaks is just S.O.P. but the motion detector would prevent the compressor from running constantly due to some failure - like the time I had a HF filter/dryer blow apart. I don't know how long it had been running when I finally noticed it, but it was long enough the insulation paper (no sheetrock) right at the leak looked burned.

I learned at that time to ALWAYS turn it off, and the lesson stuck. Taking that to heart like I did gives me the same net result as the OP is looking for out of the motion detector setup.

I used to have a oiless machine that was so loud that a hated it to run so fixed all leaks so run as least as possible. Now, with newer compressor its just a habit.

The 5 Stitches Garage part 1 http://www.garagejournal.com/forum/showthread.php?t=142100

The 5 Stitches Garage part2 http://www.garagejournal.com/forum/showthread.php?t=211899

 

[LS6 Tommy]

I had a posting here yesterday that seems to have gone missing. LOL.

You can remove the unloader from the pressure switch & install a combo check valve/unloader. They always bleed off after the pump stops, regardless of whether the pressure switch is made or not. Those Schrader style unloaders on the pressure switch invariable end up leaking anyway.

I also have an SOP that's burned into my head. I leave my compressor tank charged, but shut the lines down. Last thing I do before leaving the shop is where force of habit comes in. I've done it so many times now it's clockwork.

1. Turn regulator down to 0.
2. Turn compressor operator "off".
3. Drain condensate from tank.
4. Turn off lights.

I used to leave the stereo amp on all the time and my shop clock has a fluorescent light in it, so I plugged the light into the switched outlet on the amp. If I walk by the garage door & see the light on, I know I left the amp on.

Tommy

 

[nehog]

Do not use an automatic switch like this on a compressor.

Say the switch triggers off while the compressor is running, almost at the shutoff point. The unloader won't trigger, leaving full tank pressure on the pump. Then the automatic switch triggers on, with full head pressure, and the motor won't have power enough to start. At that point something has got to give, and it probably will be the motor.

 

[Davefr]

a better way would be to set up the relay to shut off your main air valve. that way, if your pipe burst, or leak, your compressor is still pressurized (assuming the main valve doesn't leak) and won't run at all.

That doesn't address the scenario where the compressor itself fails, leaks down and then runs continuously until it throws a breaker or self destructs.

I'd venture a guess that this is far more likely then a downstream line rupturing.

 

[Ed ke6bnl]

Do you turn the lights off when you leave? Hook a relay to the light circuit so that if lights are on, compressors on.

I have a contactor going from the light outlet and works fine and has been up for abut 5 years.

 

[fteufert]

Have you considered a timer, like one used for a bathroom fan?

I am installing one on my compressor since my son always forgets to turn it off.

 

[pepi]

I think the BEST solution is to find and fix the air leak, or just put a sign up on the door you exit the room from reminding you to kill the power.

You're going to create a bigger problem trying to solve a simple problem, automation is a fine concept. I will assume this is a 220 machine and would suggest a timer, the same type used for pool pumps of course 220 rated.

My compressor and not bragging btw stays on 24 x 7,365, unless I am using it does not run period, it and supply piping are a 20 + year installation to be clear.

To continue there are some screwy statements above please read:

Air compressor unloader valve.
The output of the piston compressor is connected through a pipe to the air tank. When the compressor stops, the pressure in this pipe is blown off to 0 bar (atmosphere).

This is the ssssssshhh sound you will here when the ccompressor stops for whatever reason. At the same time, a check-valve makes sure only this small pipe is empty and allows the air receiver tank to remain pressurized

Why? When the compressor starts up again, and this pipe would still be under pressure, the electro motor will not be strong enough to turn the compressor.

In other words the unloader function has nothing to do with the power, strictly a mechanical function .

 

[Milton Shaw]

I would suggest using a relay off the light circuit. A lot more dependable and usable than any kind of motion detector. I would also suggest a solenoid on the outlet of the tank to cut air delivery from the tank when the light are off. If you got a relay with "NO" and "NC" connectors you could wire additional smoke detectors to turn on when the shop is empty and the lights off. Smoke detectors on all the time in a shop that has welding, running cars and other smoke producing jobs will be going off all the time.

 

[Spareparts]

The only problem with a holding circuit confrigation is the compressor will not build enough pressure with a major leak to shut off automatically so your back to step one. I just added another light switch above my light switch for my shop lights, when I leave for the day/night both switches get turned off.

 

[Davefr]

Air compressor unloader valve.
The output of the piston compressor is connected through a pipe to the air tank. When the compressor stops, the pressure in this pipe is blown off to 0 bar (atmosphere).
This is the ssssssshhh sound you will here when the ccompressor stops for whatever reason.

This is not necessarily true. At least with many compressors including mine.

What actuates the unloader valve to fart off pressure is the pressure switch toggling to off when the tank is full. (100% mechanical via cable linkage)

If you stop the compressor by killing power and the tank is not full then pressure will not be "unloaded". (ie there is no ssssssssh unless the pressure switch and only the pressure switch turn off the compressor.

 

[sberry]

I have 2 comps, finally figured I didn't need the breaker on to the second. I use all the tanks, about 200 gallons. I have a shady hose or 2 due for replacement and have a couple things isolated via valve.

Mine is on 24/7, never totally shut off. I had a regulator problem a while back and in a hurry to fix simply added a t and a hose as a jumper. Today I finally picked the pieces up and drilled out a broke ******, repaired it like its sposed to be.

I leave a lot of it live, never had it happen. Have always managed to pre empt finding a leak but have one outdoor that is decades behind its service life and I should replace the feed hose to my steamer.

A small garage doesn't need gobs of connected equipment. Keep it in good shape. I unplug tools from hoses to prevent leaks. So much of it is coupler related. If its not leaking its not running.

 

[willymakeit]

Hang a sign by door that says turn off compressor.:

 

[jcouch1]

why not use the timer to shut down compressor and close discharge line so that you never run the compressor and always have a full tank!

Good ideas.

I put a 120v solenoid valve on the line of a compressor to function as a bleed down. old centrifugal bleeder broke, so we took the parts out and used the electric valve to fix the problem. Been running good for several years now.