Does my (light use) air compressor need a working pressure switch?

[pkpk]

Hi all, first post here but google searches have sent me here many times (a thread on Craftsman-branded worm drive Skilsaws is what convinced me to pick one up for super cheap a couple months ago) and I figured I should join the fun. I'm no pro, just a DIYer who does some woodworking and is now learning how to fix up tools, so I'm looking forward to soaking up knowledge and sharing photos of some of the neat vintage stuff in my collection.

Anyway, pardon another thread about air compressors...

I bought a used Senco pancake compressor (model PC1280) a while back and the pressure switch seems to be shot. It's rated 150psi max but when tested the motor labored as it got close to 170psi before I shut it off just to be safe.

I wanted something for air nailing (had to put in some new interior trim) along with tire inflation and cleaning off work surfaces etc, nothing heavy-duty, and to me it's already paid for itself. I'm fine running the motor for a minute or two, always being sure it doesn't go above 150psi, then turning it off until/if I need more air. I know the pressure switch is an easy replacement but I'd rather not pay the $20 for the part if I don't have to yet. Is there any problem or risk using the compressor in this way?

Bonus question: I recently won a 1995 Craftsman Industrial pancake compressor (model 919.153451) via online auction. I could see from the pictures that it'd been placed outside, and a rainstorm passed over the pickup site just before I arrived. I didn't think it was good for these to be left out in the elements...? Anyway when I got it home, I opened the drain valve, expecting the usual few spurts of dirty water, but this one probably put out around 8oz, maybe more. But aside from that, and a missing air filter, it seems to run totally fine. Given there may have been water sitting in this old thing for a long time, should I be worried about the integrity of the tank?

Thanks for any input!!

 

[The Cobbler]

the pressure switch is a safety device. it should be operational. if you choose to be lackluster with spending $20 on a repair, use at your own risk. to me a $20 repair for the convenience of not having to worry bout manually turning it on/off is pocket change.
a simple rainstorm will not hurt a compressor tank. the water in the tank wasn't from the rain, but condensation in the air as it compresses and it wasn't drained off for some lenght of time. I wouldn't worry about it either

 

[TuxThePenguin]

Risking my safety for the $20 part would be exceedingly stupid in my opinion.

Do you value yourself that little?

 

[MoonRise]

Pressure switch is an ESSENTIAL safety device.

Replace it ASAP. NO debate, no option, no choice. Replace it!!!!!!!!!!!!!!!!!!!!!!!!!!

Risks? Burning up the motor, burning up the wiring, tank catastrophic failure complete with property damage and injury and possible death. No joke.

Also check the condition and operation of the pressure relief valve. It is also an ESSENTIAL safety device.

The pressure switch turns the pump motor on and off. The pressure relief valve is there to release 'excess' pressure if the pressure switch fails so that the tank doesn't fail.

If the tank is 'rated' for a certain pressure (psi, and it should be on the tank label), then you do NOT use a pressure switch with a higher psi than that. EVER! You can certainly use a lower psi pressure switch if you want to.

 

[pkpk]

Thanks for the responses!

I was wondering if the pressure switch was actually considered a safety feature if, like I said, besides that initial test I would never allow it to stay on past 150 psi (and usually only ~140 psi) for my light use. I rarely even need to reload the tank for what I'm doing so I was thinking that pressure switch isn't being put into action anyway.

Safety is #1, I'm happy you guys are pushing that, but money is tight and I didn't think for my use I was risking any sort of motor or tank failure. I mean, wasn't there maybe a time before pressure switches were common, when someone using a compressor would need to be smart and aware, watch the psi gauge, and manually turn the motor on and off as necessary? Like, their brain was the main safety feature?

And I'm generally familiar with how air pressure works and definitely know to get the right/matching parts especially in terms of safety features. The pressure relief valve on this one actually says 170psi, do you think that's a mismatched replacement? Not that I wanna test it, but I figure these things are probably made to at least briefly withstand 200psi, and the 150 (or 170) ratings are to be on the very safe, lawsuit-avoiding side... should the relief valve rating exactly match the tank rating?

About the other compressor outside in the rain: I was wondering if the drainage could have been from some rainwater slipping in, besides any accumulated, unrelieved condensation. But if there was 8oz or more of water sitting in there for years, would that be cause for concern? And just to be clear, this one is 120psi max, and it has a 150psi relief valve, and YES it does cut out at 120psi!

Thanks again!

 

[pancho400cid]

Welcome to the forum.

I'll beat the dead hose some more.

Compressor tanks contain ENORMOUS amounts of energy. If a 2 HP motor runs five minutes to fill it before it shuts off then you have "about" 10 horsepower-minutes on tap... to do useful work or hurt people and break stuff.

Fix the switch ASAP. Don't run the compressor until you do.

Lastly - a recent thread:

https://www.garagejournal.com/forum/showthread.php?t=460702

 

[pkpk]

Welcome to the forum.

I'll beat the dead hose some more.

Compressor tanks contain ENORMOUS amounts of energy. If a 2 HP motor runs five minutes to fill it before it shuts off then you have "about" 10 horsepower-minutes on tap... to do useful work or hurt people and break stuff.

Fix the switch ASAP. Don't run the compressor until you do.

Lastly - a recent thread:

Haha, I don't mind any beating! I appreciate the responses, and I'll probably add the pressure switch to the cart next time I do an online order. And that story is scary (had to remove link from quote as new member). I remember once being with my dad as he was working on one to sell that might have been about that big - a very old green thing that looked almost like an A-bomb pointed down - and being a little nervous when he turned it on to test it.

But I'm still left asking why this is so essential in my case. The Cobbler kind of hit at my point by mentioning convenience...but I don't know how I'm entering the realm of "unsafe" by running an air compressor for a minute or two at most, to fill its tank once or twice, below its max psi. (And then using what I need, venting off the rest and draining out any condensation.) If the pressure switch's job is to cut off a motor at that max psi to prevent motor or tank failure, I don't see a job for it in this case since I'm there to prevent the motor and tank failure by manually keeping well within the limits.

I just sold a tool to someone in the trades tonight, I'm sure he was smarter than me on this stuff. I asked him this question about the pressure switch, and he didn't see any issue with not replacing (or fixing?) it given my light use...

 

[The Cobbler]

the issue may not be with you per say, but with someone that plugs your compressor in while you're sick in the hospital, to fill your wife's or kids tire , not aware that it needs to be manually shut off...
you can probably go thru life with no issues with it, but is it worth risking for $20?
Only you can answer that I guess

 

[pancho400cid]

Yeah.... it's the requirement for true and constant attention that makes it dangerous.

You never know when a buddy, spouse, kid etc. may turn it on and walk off.

You're gone.... your wife's tire is low. The son-in-law volunteers to air up the tire....

Etc. Etc. Etc.....


...

 

[pkpk]

Valid points and duly noted - but no wife or kids for me just yet, and not too many other friends, neighbors etc who'd go mess around with my tools.

I guess my reasoning is, to me the compressor has paid for itself and I'd be really happy if it lasts me as is until I move out of state within the next half-year or so, then I'd leave it behind. But maybe I'm underselling it (and Senco?) I bet this thing is at least ten years old, but do you guys think especially with a good pressure switch and just my usual light or at least not heavy professional use, it should last me a lot longer?

Last thing for now then, because this seems important: should the pressure relief valve rating exactly match the unit's max psi rating? I figured a little difference is normal, especially with the expectation of a working pressure switch to cut off the motor.

Thanks again, hopefully you're not too annoyed at the new guy!

 

[jonesg]

These guys are pussies, whats the worst that can happen.

 

[pkpk]

These guys are pussies, whats the worst that can happen.

Yeah, that video is scary but I'm not sure what your point is about those guys being "pussies" - fwiw this has never been a question of 'manliness' or pride for me - or how their situation applies to mine, with a small air compressor, that nobody else touches, that I *always* monitor for the minute or two the motor is on, then switch off before it hits max psi...?

In that video it seems they left their compressor running un-monitored and hadn't checked the relief valve was working beforehand, and the thing blew up because of over-pressurization, right? Unless it suddenly failed within its limits (ie factory defect), isn't that a clear case of user error, and not knowing their tools?

 

[Zebu Fellenz]

You still have a pressure relief valve even if the pressure switch is bypassed. The relief valve should be factory set to open at a lower pressure than will cause catastrophic failure of the tank/etc. This pressure may still be higher than the compressor is able to achieve before the motor stalls (which could lead to overheating or complete failure of the motor).

Replacing the pressure switch is a good idea and would be well worth $20 (to me) for the peace of mind. But I also think the chances of catastrophic failure are pretty low if your pressure relief valve (the other safety system) is working correctly.

 

[pkpk]

You still have a pressure relief valve even if the pressure switch is bypassed. The relief valve should be factory set to open at a lower pressure than will cause catastrophic failure of the tank/etc. This pressure may still be higher than the compressor is able to achieve before the motor stalls (which could lead to overheating or complete failure of the motor).

Replacing the pressure switch is a good idea and would be well worth $20 (to me) for the peace of mind. But I also think the chances of catastrophic failure are pretty low if your pressure relief valve (the other safety system) is working correctly.

Thanks for the pressure relief valve info! Yup, I've tested them for both the Senco and the Craftsman, they each open smooth and fast under higher pressure and close fully.

Anyway I'll probably get a new pressure switch soon...

Last question for now: if you guys had to choose one compressor to keep, which would it be?

Craftsman Industrial 919.153451 from 1995: 4 gallon tank, 1.5hp, 120psi max, 3.3scfm at 90psi
Senco PC1280, unknown age: 6 gallon tank, 1.5hp, 150psi max, 2.8scfm at 90psi

The Senco is lighter and actually a little more compact, and newer I'm sure, and when I ran a test just shooting 90psi air out of a nailer, it definitely had more capacity, that 150 vs 120 max psi seems a big advantage. But especially if that accumulated water I drained off wasn't a big problem, the Craftsman just feels really sturdy to me and like many I've got a soft spot for old Craftsman tools. I actually have what was my dad's old 30 gallon Craftsman compressor that also has a 1995 sticker date, and I know it was a workhorse for him. (I haven't used in a year because no 220v outlet available where I'm at now... it might end up with someone else in the family who will use it more and has the space)

I think the brain says Senco, but the heart says Craftsman...

 

[pancho400cid]

There was a "relief valve" on the compressor that launched itself into the pool in the linked vid...

 

[American Locomotive]

Just get the pressure switch if it's only $20. It's not worth the hassle of baby sitting the compressor every time you want to use it for $20.

I think the Senco is probably the better compressor. It's certainly much newer. But I wouldn't say it's vastly better or anything.

 

[danski0224]

No pressure switch needed.

Just install a piece of PVC piping as a primary pressure release, and you should be good...






















That's a joke, for those who can't figure it out.

 

[mike93lx]

just replace the switch.

compressors are incredibly dangerous when something goes wrong. i would love to not even need one at all

 

[jonesg]

Yeah, that video is scary but I'm not sure what your point is about those guys being "pussies" - fwiw this has never been a question of 'manliness' or pride for me - or how their situation applies to mine, with a small air compressor, that nobody else touches, that I *always* monitor for the minute or two the motor is on, then switch off before it hits max psi...?

In that video it seems they left their compressor running un-monitored and hadn't checked the relief valve was working beforehand, and the thing blew up because of over-pressurization, right? Unless it suddenly failed within its limits (ie factory defect), isn't that a clear case of user error, and not knowing their tools?

ok, I'll explain ironic humor.

Irony (from Ancient Greek εἰρωνεία eirōneía, meaning 'dissimulation, feigned ignorance'[1]), in its broadest sense, is a rhetorical device, literary technique, or event in which what on the surface appears to be the case or to be expected differs radically from what is actually the case.

 

[Monza Harry]

Get an appropriate blow off valve, I feel 175# is way too high! I am presuming that is a single stage pump, so max efficient pressure will be closer to 125#'s not 150#'s the blow off should be a 150#'s not 175. As for the switch, the time to correct that is NOW not soon, remove the cord untill corrected! That switch will work even when you run out to help the child who was just hit by a car, the neighbors or your own place is on fire, or you suffer a medical problem ) heaven help us that none of these ever happen!.We just aren't able to predict the future with any real accuracy. You could remove a fitting and use a borescope and look at the tank bottom and decide if it is sound. Let's be as safe as we can! Harry

 

[70Mach1]

So $20 is too much on your tight budget, but you could afford to buy a second compressor off the auction site? I Right. . . .

 

[JRC3]

I didn't read all the replies here, but I'm just gonna drop this. With tax we're talking $16. https://www.ruralking.com/powermate-pres-switch-105-135psi-4-port-034-0226rp There is no way in Hell I would let that switch go. I probably would to get me through a day of very light work, and then it would get replaced that very night.

I have the same switch on my 60G. I also replaced the pop off valve at the same time, $5.

 

[JRC3]

So I just looked up that model of compressor. I've never seen one use a switch like that, my 6G Porter Cable has a full size switch on it.

Senco part number 9063227 and I come up with this on ebay. for $16.15 to the door. https://www.ebay.com/i/391553970748...9TdMwRAZTwHZFuIgA6t5QymIMQUMLYaBoCFGwQAvD_BwE

That little thing looks like it's for a dummy oil light, kinda scary IMHO.

 

[pkpk]

So $20 is too much on your tight budget, but you could afford to buy a second compressor off the auction site? I Right. . . .

I didn't mind the financial gamble and I've had great luck through this auction service.... so for about $15 I ended up with what looks like a fully functional compressor vs ~$20 for a single part. Not a bad deal for this amateur/DIYer, I'd say!

I can see like a lot of you run your compressors a lot more than me, and have family, friends, neighbors etc around your shop/garage/tools, and I'm pretty much a lone wolf at the moment... but I get it! Safety first.

Anyway, I see one vote for the Senco over the Craftsman, any others wanna chime in? (To be clear this comparison is with the Senco having a working pressures switch)

And then there's the question of the relief valve, seems there's some differing opinions here about what they should be rated at vs the compressor's max psi... The Senco looks like its relief valve was replaced since I see some excess thread tape vs the Craftsman's which looks pretty clean and untouched. But both have that 20-30psi difference with the relief valve.

Thanks again everyone, I like asking questions and I know this is a pretty basic one but appreciate you all taking the time to speak up.

 

[Citation]

Hi all, first post here but google searches have sent me here many times (a thread on Craftsman-branded worm drive Skilsaws is what convinced me to pick one up for super cheap a couple months ago) and I figured I should join the fun. I'm no pro, just a DIYer who does some woodworking and is now learning how to fix up tools, so I'm looking forward to soaking up knowledge and sharing photos of some of the neat vintage stuff in my collection.

Anyway, pardon another thread about air compressors...

I bought a used Senco pancake compressor (model PC1280) a while back and the pressure switch seems to be shot. It's rated 150psi max but when tested the motor labored as it got close to 170psi before I shut it off just to be safe.

I wanted something for air nailing (had to put in some new interior trim) along with tire inflation and cleaning off work surfaces etc, nothing heavy-duty, and to me it's already paid for itself. I'm fine running the motor for a minute or two, always being sure it doesn't go above 150psi, then turning it off until/if I need more air. I know the pressure switch is an easy replacement but I'd rather not pay the $20 for the part if I don't have to yet. Is there any problem or risk using the compressor in this way?

Bonus question: I recently won a 1995 Craftsman Industrial pancake compressor (model 919.153451) via online auction. I could see from the pictures that it'd been placed outside, and a rainstorm passed over the pickup site just before I arrived. I didn't think it was good for these to be left out in the elements...? Anyway when I got it home, I opened the drain valve, expecting the usual few spurts of dirty water, but this one probably put out around 8oz, maybe more. But aside from that, and a missing air filter, it seems to run totally fine. Given there may have been water sitting in this old thing for a long time, should I be worried about the integrity of the tank?

Thanks for any input!!

 

[pkpk]

So I just looked up that model of compressor. I've never seen one use a switch like that, my 6G Porter Cable has a full size switch on it.

Senco part number 9063227 and I come up with this on ebay. for $16.15 to the door. https://www.ebay.com/i/391553970748...9TdMwRAZTwHZFuIgA6t5QymIMQUMLYaBoCFGwQAvD_BwE

That little thing looks like it's for a dummy oil light, kinda scary IMHO.

Thanks for looking, I actually found it at https://www.ereplacementparts.com/pressure-switch-p-1837147.html ....it'd be about $7 more to ship alone but it's in my cart along with some other stuff.

And yeah, I'd noticed the different size/type too, but does yours also work as the power switch?

 

[pkpk]

I'm also a Hoosier but more importantly a huge fan of old Simpsons, so with that clip I understand and value your point more than anyone else here! LOL

 

[JRC3]

but does yours also work as the power switch?

Yep.

 

[Lassen Forge]

Ever seen a compressor blow up? Or been in the same area where one goes off?

Compare the size of a hand grenade to a compressor tank of any size without a pressure relief.

What fun. Yeah. May as well plumb in some Sch40 PVC for air lines, too.

So yeah, sorry for the sarcasm, but what's your life worth?

 

[Gotcha640]

I'm in the replace it camp. I'm super tight with money, agonize even over maintenance items, but my approach would be to leave it off until the switch is replaced. What if you get distracted? What if the switch gives up and you have to go pull the plug? What if you get stuck under a car/tree/etc etc etc and can't shut it off?

I'll also say that if you're willing to maintain it, an air compressor should last a long time. New pressure switch now, new start capacitor next year, oil change every so often, drain the tank once a month or so.

The alternative is not to use air tools. You got along fine without it before, I rebuilt engines and most of a 68 bronco and built furniture without a compressor. It's really nice to have one now, but if I couldn't keep it running safely, I'd be back to hand tools.

 

[pkpk]

I almost feel like your guys' compressors live more exciting lives than mine right now! Point taken, I'll get a new pressure switch.

I'll also say that if you're willing to maintain it, an air compressor should last a long time. New pressure switch now, new start capacitor next year, oil change every so often, drain the tank once a month or so.

Both of these are oil-less, but yeah, maybe I underestimate how long these can last with a little maintenance.

Anyway if anyone has advice, here's the Craftsman, which needs a new air filter. With the mud and dirt gone, I think it looks pretty good for 25 years old. I can't find any info on this specific compressor (919.153451 ....there's a wheeled one with a similar model number that shows up on google), so can't look up the exact air filter. But I have these - https://www.amazon.com/dp/B008JVLYU2/?tag=atomicindus08-20 - could I just cut one down to size and jam it in there?

 

[Citation]

I almost feel like your guys' compressors live more exciting lives than mine right now! Point taken, I'll get a new pressure switch.


Both of these are oil-less, but yeah, maybe I underestimate how long these can last with a little maintenance.

Anyway if anyone has advice, here's the Craftsman, which needs a new air filter. With the mud and dirt gone, I think it looks pretty good for 25 years old. I can't find any info on this specific compressor (919.153451 ....there's a wheeled one with a similar model number that shows up on google), so can't look up the exact air filter. But I have these - https://www.amazon.com/dp/B008JVLYU2/?tag=atomicindus08-20 - could I just cut one down to size and jam it in there?

Don't jam anything into that intake tube. You will reduce the air intake too much. You might be able to thread or glue something like this into that intake
https://www.amazon.com/dp/B07MJC5689/?tag=atomicindus08-20
You could also slip some brass or other tube into that intake, glue it in, then attach a threaded filter housing. Here is a copper pipe to NPT adapter. No idea if this and the filter above are compatible but with a bit of epoxy this sort of trick would let you use a screw on filter
https://www.lowes.com/pd/NIBCO-1-2-in-Copper-Threaded-Adapter-Fittings/3505168
BTW, from personal experinence, this sort of filter
https://www.amazon.com/dp/B008JVM0F0/?tag=atomicindus08-20
plus about 18" of rubber or vinyl tube slipped over the intake snout of the filter housing makes for a very effective intake muffler. When compared to your open intake you can do quite a bit to reduce compressor noise.

As for the pressure switch, these are largely generic but there are a number of different versions of the same things out there.
https://www.amazon.com/dp/B00QI34K5E/?tag=atomicindus08-20
That one looks similar to the one in the picture (look for a brand name inside/on the part and search for that, not the Cman number). The differences are often things like does it have an unloader valve or not, does the power cord come from the bottom or side, what are the preset pressure limits (cut off at 135, vs 150 etc), is the base a single inlet or a 3-way T (in from tank, out to pressure regulator, out to blow off valve). Those preset limits can all be adjusted so if every thing else is right, by the switch.

 

[Gotcha640]

I have a very similar craftsman compressor, it's just the compressor and the pressure switch, for tires and such. It's been great for that use, and kids inflatable pools and slip n slides and such.

It's been good for filling a bunch of kids bike tires at the school bike day, family and friends cars that come by for dinner, no problems. Clean it up, and it should be great for another 20 years.