Compressor timer?

[cadunkle]

Searching I can find a lot of threads here where people mention wanting a compressor timer and a few where people mention installing one but with no details. I was at Depot today and saw the hotel and storage unit style turn knob mechanical timers typically used for lights. This got me thinking about putting a timer on my compressor again, since I finally had a failure that it ran for over 24 hours. Belt was slipping and melted into the pulley before failing, then motor spun for a great time at no load. No Lasting damage, but this recent failure got me thinking.

They make these timers in larger time intervals as well, either 12 or 24 hour maximum on duration and some have a hold on function to override the timer. For simplicity sake I'd think a 12 hour timer would work well for me as I'd tend to just turn the knob and I'd be good for the rest of the day. I do not use air every day, my system is still a bit leaky from recent additions. I'll eventually get to fixing the leaks but either way prefer an auto off functionality, particularly since my compressor is in another building above the ceiling, out of sight, out of mind, and you can't hear it from the garage. The problem with the timer switches I can find is they are rated at low amps and I have a 5hp compressor.

A couple years ago I followed the example in this post (https://www.garagejournal.com/forum...ntactor-with-a-thermostat.388491/post-7583900) to use a wifi thermostat to control 240v electric heat with a smart thermostat working a contactor. I'm thinknig I should be able to do the same thing for the compressor, but instead of a thermostat controlling the low voltage side of the contactor I'll use a machanical timer switch (https://www.intermatic.com/Catalog/...ValueIds=fcdaefa0-6844-4ff8-b148-ad3e00d90a79). Anything to be aware of for this? Is there an easier or better way than what I'm thinking of?

 

[Citation]

If you use a magnetic starter then this is a reasonably simple job. All you have to do is interrupt the pressure control line. If you have a more basic compressor (pressure switch directly controls the motor) then perhaps consider adding a magnetic starter.

 

[Junkman]

Most light timers will not handle the amperage of the compressor unless your compressor has a small motor. I would use a contactor for the compressor current, and the timer to turn the contactor on and off. At my wife's store, we have all the lighting on contactors, and a single throw of one light switch will turn them all on. I did this in every store in our chain originally and it kept people's hands out of the circuit breaker boxes and made mistakes like turning the refrigeration system off, etc.

 

[nadogail]

I use a 30 minute twist timer, a 24 plug in power supply and a 40 Amp rated relay to control the Electric Heat in the detached garage where my wife and her Housekeeper sometimes spend some time.

The Power Supply was repurposed from a Sprinkler Timer. The Relay and it's enclosure were ordered from Automation Direct (formerly known as PLC Direct)

 

[pcmeiners]

Rigged this for my Quincy 325, it is the ultimatic protection for the unit, look at the use of dual timer relays.......

Quincy 325 Control modification

Made modification to control my QR 325. Added one dual time delay relay to lock out the power contactor should the compressor run continuously for more the a specified amount of time, so at the moment ,if it runs continuously for more then 1 1/2 hours it shuts down, and locks out until a...

www.garagejournal.com

"Most light timers will not handle the amperage of the compressor unless..."

You run the relay coil of a contactor through the relays contacts, very small current draw.

Link may not work but search Ebay Dual timer relay ....

they look like this, they make them in different voltages

Time Delay Relay Timer Switch 220V Flexible Large Capacity Sensitive Double | eBay

Find many great new & used options and get the best deals for Time Delay Relay Timer Switch 220V Flexible Large Capacity Sensitive Double at the best online prices at eBay! Free shipping for many products!

www.ebay.com

 

[no704]

Use a pool timer.

 

[fourjeepin]

Use a pool timer.

That would work. If you only install the off switch and manually throw the switch to turn it on, it would work like the mechanical light timers the OP mentioned. You could set it to run for a max of 24 hours before it would shut itself down.

 

[CraigStu]

My current compressor is on a twist mechanical time. It is 120V and the timer is the best thing I have ever done. Because I also have a slow leak at one hose reel I also found an electrically operated air valve. So I agree you will really like it. A bit more relevent, in our previous house the previous owner had a second drive where he parked his RV and had run 240V out there into a box on a pole. He put the RV connector and regular 120V outlets in the box. So I ran a bunch of motion activated flood lights out of the box for walking our dog at night. Cars on the road or wind moving tree limbs would always turn on the lights. So in the house basement I cut into the 240 wire and installed a contactor which I controlled w/ a normal 120V wall switch near where we walked out w/ the dog. You could easily do the same thing but control it w/ a timer. The electrical supply house didn't like to help a regular person at all so finding the proper contactor took some research. Be sure to get enough contactor amp capacity to account for compressor startup load not just running load. Check the amps of the 120V control circuit just to be sure but I remember it was very little so nearly any timer will work. BTW my compressor timer is just 60 minutes because it is handy to get to in the garage. There are a few times I have had to turn it back on but not that many.

 

[shopnut]

I ended up installing a mechanical Intermatic 220V 7-day timer on my 60 gallon unit. Instead of using the "ON" triggers on the timer wheel to power up the compressor every day (I'm not out there every day), I rigged up an external lever (because the timer is hidden inside a larger enclosure) to switch the timer contacts on only when I need it and the timer is used to perform the "OFF" function only if I forget to turn it off in the evening.

This shows the external lever, which was just a push mower throttle control I had laying around. It has the same sharp snap action of the timer contacts.


And this shows the overall control panel with the main switch down at the lower right. The small 12-hour timer you see at the upper right controls a ball valve to open and provide air to the shop, and it is on a 120V circuit along with some other systems.


This link will drop you into my build thread in the appropriate spot:
https://www.garagejournal.com/forum...hday-to-me-est-2005.3148/page-71#post-4087895

 

[The Cobbler]

^^^ i kind of like that idea. but when do you have the off trippers set for shut off ?

 

[shopnut]

^^^ i kind of like that idea. but when do you have the off trippers set for shut off ?

Well, conceivably with my 7-day timer, I can set the OFF time different every day if I wanted to. In reality, I believe my weekday time is 9:00pm and weekends are set a few hours later. This is overkill, of course, and a cheaper 1-day timer would have been fine with an OFF setting of maybe midnight repeating every day. The 7-day timer was the only one I had on hand that would handle the current of my compressor, so I figured, why not?

 

[cadunkle]

My compressor does not have a magnetic starter, though from reading about them it seems like 5HP is about max to run direct through a pressure switch and can burn them up. It's the 5 HP HF compressor with a T29s pump, basically a cheaper Belaire 216v.

In any event, I'm inclined to add a magnetic starter, which I wasn't familiar with but is basically a contactor and thermal overload sized for the motor load. Should be simple enough to do once I figured out the wiring. The contactor is controlled by the pressure switch, and I can just use any twist style mechanical timer inline with the wiring from the pressure switch.

Any suggestions on what magnetic starter to get? I see a bunch of options from $50 China specials to $200+ for some from the models from name brands. Looking for a 5HP 240v single phase in a box ready to mount to the wall next to the compressor.

 

[Citation]

My compressor does not have a magnetic starter, though from reading about them it seems like 5HP is about max to run direct through a pressure switch and can burn them up. It's the 5 HP HF compressor with a T29s pump, basically a cheaper Belaire 216v.

In any event, I'm inclined to add a magnetic starter, which I wasn't familiar with but is basically a contactor and thermal overload sized for the motor load. Should be simple enough to do once I figured out the wiring. The contactor is controlled by the pressure switch, and I can just use any twist style mechanical timer inline with the wiring from the pressure switch.

Any suggestions on what magnetic starter to get? I see a bunch of options from $50 China specials to $200+ for some from the models from name brands. Looking for a 5HP 240v single phase in a box ready to mount to the wall next to the compressor.

Your motor should have a thermal overload built in (look for the reset button). Assuming it does then you can use a contactor without overload protection. I don't think there is an issue with using a motor with overload with a contactor that also has overload.

 

[Norcal]

A Intermatic T101 has a 40A rating, wired into the control circuit of a mag starter is best though, & the 40A rating would not be needed, most common models have 120V, or 208-277V, timer motors.

 

[BillK]

Sorry, I just cannot fathom leaving it on at all if I am not in the building. Even with the timer are you always going to be there when the timer is on ?? I have been in business since 1987 and its just part of my routine. I turn the compressor on in the morning when I walk in the door and off when I leave. At home the only time the compressor is on is if I am in the shop.

 

[NeubCont]

I installed this in my garage from Amazon
Works great for me! Is Wi-Fi Compatible- Set timer schedule to go on/off when you want
If I have a minute I will post pix tomorrow

Suraielec WiFi Pool Timer, Outdoor Indoor Smart Switch, 40 AMP, 2HP, 120, 240, 277 VAC, Heavy Duty Pool Controller Light Timer Box for Pool Pump, Water Heater, Spa, Powerful Electrical Appliances​

 

[Firebrick43]

Why not just use a mini PLC ? All you would need is the PLC and its power supply, a contactor, and a switch(or multiple switches). By going that route you can control it the compressor however you want, limited by your imagination. Want it to start only if you push one button 5 times and another 3? You can do that. Want timer to run, timer to stop, timer that shuts off a 9 pm no matter what, you can do that. Want to turn the compressor on while your on a business trip to spain, if its got an ethernet connection you can do that to. It can monitor your hours and flash a light when the oil needs changed.

 

[Norcal]

I installed this in my garage from Amazon
Works great for me! Is Wi-Fi Compatible- Set timer schedule to go on/off when you want
If I have a minute I will post pix tomorrow

Suraielec WiFi Pool Timer, Outdoor Indoor Smart Switch, 40 AMP, 2HP, 120, 240, 277 VAC, Heavy Duty Pool Controller Light Timer Box for Pool Pump, Water Heater, Spa, Powerful Electrical Appliances​

Your much better off with a old skool mechanical timer, much more reliable & also avoid off breed brands too.

 

[CraigStu]

Sorry, I just cannot fathom leaving it on at all if I am not in the building. Even with the timer are you always going to be there when the timer is on ?? I have been in business since 1987 and its just part of my routine. I turn the compressor on in the morning when I walk in the door and off when I leave. At home the only time the compressor is on is if I am in the shop.

Bill your use case is different due to your relatively regular schedule. Yesterday I was working on a project that had me in the garage using an air cutoff grinder. Several trips to the garage over 3 hours. I cranked up my compressor w/ the 60 min timer. Later I had to add another 30 min. Later our SIL stopped by and we spent an hour chatting etc. At that point I decided my project could wait til tomorrow. 50 some years of having a garage compressor caused me to think, as he was leaving, I better shut it off. I actually started to the garage but by my second step, oh wait my timer will turn it off, looked at a clock, hey in fact it already has. Best compressor related thing I have ever done.

 

[cadunkle]

Sorry, I just cannot fathom leaving it on at all if I am not in the building. Even with the timer are you always going to be there when the timer is on ?? I have been in business since 1987 and its just part of my routine. I turn the compressor on in the morning when I walk in the door and off when I leave. At home the only time the compressor is on is if I am in the shop.

Very different use case for your livelihood that you do more or less every day, as compared to home use which could be every day for a week and not used again for another couple weeks. I may be in the garage every day, or not for several days. I only need air sometimes. If you are working in the building every day and need air every day it's super easy to get into a routine of things to turn on and off every day. That is not my use case.

I ordered a Square D 8911DPSG32V09 and Intermatic FF12HC 12 hour timer switch. If I'm only airing up tires it'll be on for the two hour minimum and only cycle once if there's not enough air still in the tank to start. I've forgotten to turn compressors off before and they have been left to cycle on/off for days on end due to leaks been fine. It took about 17 years of having a compressor to get unlucky and burn up a belt... Not a big deal in the scheme of things but may not have happened with a timer. Anecdotally I think any sort of unattended compressor failure is fairly uncommon in general, more so if limiting potential compressor run time with a timer.

 

[CraigStu]

It happens that my compressor is in the right rear corner of the garage. The door to the house in in the left front corner. I tried adding big yellow flags to the switch and the manual outlet valve so I could look from anywhere in the garage and be able to see if it is on or the valve is open. Horizontal = on or open. But you still have to remember to look at them. Now I don't have to remember squat.

 

[niget2002]

I like the idea of the Intermedic pool timer for shutting off the compressor at the end of the day. It's not a bad price.

I don't even turn the air compressor on every time I go out to the shop, so I'm not always in the habit of turning it back off. I usually do pretty good as I turn off the ball valve to the rest of the piping when I turn it off, but every so often I'll hear the AC kick on late at night after I'm back in the house. My piping has a small leak that will air down over time if I don't turn the ball valve off that triggers the AC to kick on.

 

[cabranch47]

I wired my compressor power cord to a 240V, 40 amp relay with 120V Coil controlled by my shop lights. Lights on, compressor on. Lights off, compressor off. Works great for me and no worries of compressor running due to leaking down or major plumbing failure.

 

[ez-duzit]

Sorry, I just cannot fathom leaving it on at all if I am not in the building...the only time the compressor is on is if I am in the shop.

This.
Adding a friggin timer because you can't remember that you turned the compressor on? WTF is wrong with turning the compressor on when you need it, and turning it off when you finish?

 

[Citation]

This.
Adding a friggin timer because you can't remember that you turned the compressor on? WTF is wrong with turning the compressor on when you need it, and turning it off when you finish?

Easy, most of the time the compressor is not running so it's easy to miss that it's in automatic mode. I don't think anyone fails to notice when the pump is actually turning but it is easy to forget to switch it from auto to off, especially if you don't have a set routine when leaving the garage/shop. I have some things I do every day so it's easy to follow a routine to make sure they happen. I don't work in my garage all the time and when I use the compressor I might power it on to use it during the first hour then not use air for the next three. Now it's late at night and the compressor isn't running or I start talking with family/neighbor etc. It's easy to forget the compressor is on since it's not making any noise and, in my case, it takes at least a few hours for the pressure to drop from "full" to "refill" if leave the hose connected with the blow gun or air chuck and I forget to close the air valve at the tank.

I wouldn't mind adding a timer to my setup. I've never had the compressor damaged because I left it on but if I don't close the valve it will leak down and perhaps cycle once a day. With a lot of the timers I have some concern that the switches aren't rated to disconnect electric motors but odds are most of the time the motor would be off when the timer switches the power off. Occasionally it wouldn't but since the timer isn't the primary switch for the compressor that wouldn't be too big a concern. Not something I would do in a professional shop (in that case I would use a starter and tie in a relay controlled by the timer/lights/etc). For a home shop the timer should be fine since it's a secondary switch to a system that in theory can handle being left on.

 

[PoorUB]

I wired my compressor power cord to a 240V, 40 amp relay with 120V Coil controlled by my shop lights. Lights on, compressor on. Lights off, compressor off. Works great for me and no worries of compressor running due to leaking down or major plumbing failure.

I did a similar deal, only I have a motor starter and added a relay controlled by the shop lights in the pressure switch circuit.

 

[like2wheel]

Before I built my pole barn, I worked out of the attached garage with stairs to the basement. Tools & equipment in the basement. Compressor was downstairs located directly under my bed.
After a few 3:00am 'reminders' that I forgot to turn off the compressor, I wired it thru a water heater timer & removed the "on" pegs. Installed one "off" peg at 11:00pm. Push the button for on.
Wife was much happier.

 

[cadunkle]

I got this wired up today. A concern that may be more suited for the electrical section is that I used 14ga wire for the contactor/timer/pressure switch. The Square D 8911DPSG32V09 uses a 240v contactor. These 14ga wires are in the same enclosure as the larger wires and protected by the same breaker, but in event of a fault they could get super hot and melty. Granted the factory wiring in the starter is also way to small to be protected by a 35a breaker, and there is what looks like a reset button on the contactor though it is not labeled for purpose or amps. Presumably this is a breaker sized for the control wiring? Thoughts?

For other compressor projects I'd like to add an aftercooler, maybe an intercooler, and extend the drain to a more convenient location, since this is in a second story with only pull down stair access.

 

[Citation]

The current going from the contactor to the pressure switch should be low current. If you are really worried about it you could install something like a 5A f in line fuse.

 

[CraigStu]

This.
Adding a friggin timer because you can't remember that you turned the compressor on? WTF is wrong with turning the compressor on when you need it, and turning it off when you finish?

Jeez, I guess it is nice having a perfect memory.

 

[ez-duzit]

Jeez, I guess it is nice having a perfect memory.

That's why table saws come with all kinds of guards--for you guys that can't remember not to put your hands in the spinning blades.

We all have probably forgotten to turn off our compressors when leaving the shop. But don't you think that hanging a sign "Compressor?" on the exit door is simpler than adding a timer whose malfunction might burn down your shop/house? Jeez!

 

[racecougar]

I can get behind the "lights on, compressor on / lights off, compressor off" relay method, but relying on a timer allows for the very possible scenario that a hose, fitting, line, etc. fails and causes the compressor motor to burn up (hopefully not taking your building with it).

Personally, I just remember to turn my compressor off before leaving my shop. I drain any condensate out of the tank, too.

 

[PoorUB]

That's why table saws come with all kinds of guards--for you guys that can't remember not to put your hands in the spinning blades.

We all have probably forgotten to turn off our compressors when leaving the shop. But don't you think that hanging a sign "Compressor?" on the exit door is simpler than adding a timer whose malfunction might burn down your shop/house? Jeez!

Do you have a toaster in your kitchen? Have you heard they cause house fires?
How about a TV? A house down the street burned down. They figured the TV shorted out and caught on fire.
Furnace? Well hell, they have caused fires too! Geez, you can't have anything in your house any more, everything might cause a fire!

A timer cause a fire? That has to be a fairly rare occurrence!

I am happy to hear you have never been working in the shop and had something come up that made you drop everything, leave in a hurry and forget to shut off the air compressor.

One thing about putting up a sign as a reminder, before long you brain doesn't see it and it gets ignored.

Have you heard of Saw Stop? They build them because people get distracted and stick a finger in the blade.

And one more thing, why does what someone wants to do in their own shop bother you so much? I know guys that spend the time to wire up all kinds of automation to run lights and even an air compressor. Some people like to mess with things and have little gadgets to run things and make the day to day easier.

 

[Imatk]

I put on one of these. Been on for a bit and works great as far as I can tell.

NKTech Vibration Timer

 

[racecougar]

I put on one of these. Been on for a bit and works great as far as I can tell.

NKTech Vibration Timer

The OP is looking for a means to turn off his compressor via a timer. That is an hour meter.

 

[cadunkle]

Quite the can of worms between the distracted types like myself and the strict routine types. The starter has a Square D type DPA contactor, which has a button in the middle. I've tried reading what I can find from Square D but nothing mentions this button, whether it is a reset button or has a lower amp breaker for the coil circuit. I'm inclined to put a fuse or breaker in this circuit to protect the smaller gauge wire and prevent any catastrophic failures. Something like a panel mount breaker (https://www.grainger.com/product/CARLING-TECHNOLOGIES-Panel-Mount-Circuit-Breaker-4VA62) or fuse (https://www.mscdirect.com/product/details/54014428) could easily be mounted in the starter enclosure on a knockout hole.

An hour meter would be nice from a curiosity perspective but I don't think is necessary for my use. They are available in 240v (https://www.grainger.com/product/TRUMETER-Hour-Meter-120-to-240V-AC-3AB99) that would be easy to wire in to the control circuit and could be placed either upstairs on the compressor or starter enclosure, or downstairs next to the timer switch where I can easily see it. Maybe if I get bored one day, as mounting might require some creativity.

 

[ez-duzit]

...One thing about putting up a sign as a reminder, before long you brain doesn't see it and it gets ignored...Have you heard of Saw Stop?

One thing about Saw Stop, once you've given up responsibility for your own safety, bad things can happen.

 

[cadunkle]

One thing about Saw Stop, once you've given up responsibility for your own safety, bad things can happen.

I don't consider such safety devices to be giving up responsibility for safety. It another layer of safeguard. Plenty of guys missing digits who were always conscious and careful except that one time something different happened. Everyone is not perfect at all times. Avoiding additional layers of safety solely because people should act perfect at all times doesn't save lives or prevent injury.

Similar for other things, like commuting... I use a full full face helmet, pants with hips and knee inserts, jacket with back/shoulder/elbow inserts, quality gloves, ECE rated boots, etc. I only drive four wheeled vehicles built prior to safety reducing mandates from the DOT and EPA that reduce visibility with massive pillars, steeply slanted windshields, mirrors that reduce visibility, and so forth. I keep fire extinguishers in the house, garage, and boat. Plenty of PFDs in the boat. I consider all of these an increase in safety, to avoid accidents and reduce damage if an accident occurs.

With my compressor I can still flip the breaker off when I'm done using it as I've (mostly) done before installing the timer. Plenty of compressors come with these and similar magnetic starters which are all rated and listed for various safety standards and installed in countless homes and businesses where power is not regularly cut to them. There is no epidemic of control circuit wiring in magnetic starters (or any contactor wiring for other devices such as air conditioners or lights) burning down buildings and killing people. I just questioned whether there was protection for the control circuit wiring out of the box and if I'm unable to confirm there is, I'll add it for an extra layer of safety to protect from an unlikely fault in that wiring. For $10 it's cheap insurance against costly or dangerous but unlikely events, same as a timer, or proper motorcycle gear.

 

[Imatk]

The OP is looking for a means to turn off his compressor via a timer. That is an hour meter.

Oh sorry... my bad