My compressor cut on tonight which it does most evenings. About twenty seconds into the cycle a new terribly loud noise was emanating. It's so loud in the garage I can't stand it. Anyhow, flipped the dedicated breaker and will leave it off until it can be repaired. Any ideas what this could be would be appreciated. It sounds like a huge air leak. (FWD to the thirteen second mark for it to cut on)
My shop compressor making a loud noise
- Thread starter Chaznsc
- Start date
matt_i
Well-known member
My guess is the unloader valve is leaking thru to ambient/outside and not checking when the compressor restarts.
Cyberbear
Well-known member
That's a bad noise! Try turning the flywheel by hand to determine if it may be a mechanical problem. Make sure there is plenty of oil in the crankcase. Without any possible chance of danger, try wrapping a rag around the unloader valve and see if the noise volume changes, then you'll have a better idea of what the problem may be.
matt_i
Well-known member
It looks to me from the video that the air leak is next to the pressure switch (likely also the unloader valve is a part of this) on the top end-bell of the tank. Something starts blowing around there when the motor starts. Maybe put your hand there to confirm.
JRC3
Well-known member
Is it oil-less? If so, the noise is normal.
LOLOLOL
LOLOLOL
Cyberbear
Well-known member
Judging from the photo, it appears to be a safety pop-off valve with the pull ring missing.
These pressure safety valves are cheap, and if one is needed and doesn't fix the noise problem, it's time to find out why.
These pressure safety valves are cheap, and if one is needed and doesn't fix the noise problem, it's time to find out why.
ishiboo
Well-known member
Definitely looks like the pressure relief. Did the preassure gauge show it was over pressure when it blew? If so, you'll need a new pressure switch or have to adjust the existing one. If not, reset the pressure switch if it hasn't done it itself (it's just a spring, so it should go back on its own) and see if it does it again.
JRC3
Well-known member
^
Replace it...And be thankful it was something so cheap and easy.
Replace it...And be thankful it was something so cheap and easy.
JRC3
Well-known member
I replaced mine a year or two ago when it crapped out. There's a tag on my tank that rates the tank at 165 psi and switch cuts off at 135. As I recall I bought a 145 psi pop-off. Do you have a Rural King in the area? http://www.ruralking.com/catalogsearch/result/?q=safety+valve
My 60g is identical ta the one on my pancake compressor. In fact, I used the one from the pancake until I had time to replace it.
My 60g is identical ta the one on my pancake compressor. In fact, I used the one from the pancake until I had time to replace it.
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Zeke
Well-known member
Check and see that the large pulley hasn't walked out on the shaft and is rubbing on the guard.
redmondjp
Well-known member
Now everybody just hold on a minute here! Everybody is jumping the gun on this one.
You see the gray line that the pressure relief valve is mounted on? That is the interstage pressure pipe which connects the primary and secondary stage cylinders. If that relief valve is blowing, it means that the input reed valve for the secondary cylinder has failed and it's blowing back from that cylinder. There is nothing wrong with the relief valve - it is doing its job and it likely doesn't need replacing.
That pump I'm pretty sure is an ABAC/American IMC pump (as used by Belaire, Rol-Air, Harbor Freight, and a number of other compressor brands), possibly a model B4900:
http://www.i90enter.com/b4900-pump-parts/
Pull the head and inspect the reed valves, after using a gauge and verifying that the pressure in the interstage is over what the relief valve pops off at [edit - after reading above, it sounds like you have already done this, so pull the head].
You see the gray line that the pressure relief valve is mounted on? That is the interstage pressure pipe which connects the primary and secondary stage cylinders. If that relief valve is blowing, it means that the input reed valve for the secondary cylinder has failed and it's blowing back from that cylinder. There is nothing wrong with the relief valve - it is doing its job and it likely doesn't need replacing.
That pump I'm pretty sure is an ABAC/American IMC pump (as used by Belaire, Rol-Air, Harbor Freight, and a number of other compressor brands), possibly a model B4900:
http://www.i90enter.com/b4900-pump-parts/
Pull the head and inspect the reed valves, after using a gauge and verifying that the pressure in the interstage is over what the relief valve pops off at [edit - after reading above, it sounds like you have already done this, so pull the head].
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redmondjp
Well-known member
Time for a replacement pump then, or start hunting for a used industrial-grade unit on the list of Craig.I think mines a B5900 - $300 part
Can the reed valves be repaired?
redmondjp
Well-known member
If you can get the parts, absolutely. Typically you will get a valve plate and gaskets. Some people have improvised and used a feeler gauge to replace a reed valve that they couldn't obtain. If yours is a B5900, the parts list is here:
http://www.i90enter.com/b5900-pump-parts/
They show item 6 as the valve assembly, p/n 5940051. Googling that part number and wowee, you are right! $343 just for that, holy carp!
I don't know if you can separate the two halves of that valve assembly and replace individual reed valves, but at that price, I'd certainly take yours apart and see if it's possible.
Here is an article I ran across researching part numbers. Exactly my symptoms.
http://www.about-air-compressors.com/b5900-air-compressor-pump-issues-and-repair-steps.html
http://www.about-air-compressors.com/b5900-air-compressor-pump-issues-and-repair-steps.html
redmondjp
Well-known member
That's a great link! If you're lucky, you may just have a blown-out head gasket and not a valve failure. I'm completely in favor of dropping the pressure range on this unit as well so it doesn't have to work so hard - I'd probably go something like 120 psi on and 140 off or thereabouts.
The failure happened all at once, I was here when it happened. Perhaps that was the HG giving way?
Do you do that by getting a new pressure switch?
redmondjp
Well-known member
Either that, or in some cases, your existing pressure switch may have a range adjustment screw inside of it (have to remove its cover to see it probably) and you can adjust that to see what effect it has.
If it's indeed the head gasket, would this be all I need?
http://www.ebay.com/itm/like/231718...7290-0%26rvr_id%3D1135611755437&ul_noapp=true
http://www.ebay.com/itm/like/231718...7290-0%26rvr_id%3D1135611755437&ul_noapp=true
redmondjp
Well-known member
Likely so, but I have never taken one of those pumps apart, so I can't know for sure. The best thing is for you to pull the head and see what's wrong before you order any parts. There are usually at least two gaskets - one between the head and the valve assembly, and one between that and the cylinder block - not sure if they are identical or not.
JRC3
Well-known member
Interesting point, I know knowthing about.
I did rebuild a 23g 120v some years ago that was given to me...Needed a check calve and that caused it to run too much. I wound up replacing the check valve. Then replacing the reed valves and head gaskets for like $20 in parts. This was 10 years ago and oil-less and smaller so I'm sure the parts were cheaper.
I used that thing for like 6 years till the tank crapped out and I bought something bigger.
I did rebuild a 23g 120v some years ago that was given to me...Needed a check calve and that caused it to run too much. I wound up replacing the check valve. Then replacing the reed valves and head gaskets for like $20 in parts. This was 10 years ago and oil-less and smaller so I'm sure the parts were cheaper.
I used that thing for like 6 years till the tank crapped out and I bought something bigger.
James-W
Well-known member
You can buy new pumps at harbor Freight. They are relatively inexpensive, (well under $200 when on sale) only thing is, I have no idea who builds them or how good they are. But in any case it is an option available to you.
redmondjp
Well-known member
Some of the ones they have sold in the past (not sure about today) are made by the same Italian factory as the ABAC pump that the OP has.
James-W
Well-known member
I am not sure if they do or they don't take coupons when it comes to pumps, but I have heard somewhere that you can't use coupons on certain items. It may be that pumps are one of the items that you can't use a coupon for, but even if you can't use a coupon the price they are selling the pumps for when they are on sale is really decent. I doubt you will find a better price on a new pump anywhere else.
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Sharpest
Well-known member
I have the same compressor I got off craigslist for $200. (Ignore the electrical "issues")
Mine is LOUD. An app on my phone says it runs at around 90 dB. Definitely not pleasant to have indoors. I don't know if this is how it is supposed to sound;
But it will still pump up to 175, though it takes around 15 minutes to do so on an empty 80 gallon tank. I have since added a pair of franzinators and a magnetic motor starter to it. I used it to sand blast a truck headache rack awhile back and it kept up no problem while running for a couple hours continuously. I would like to take the head off to inspect the reed valves but as indicated above, the parts are way more expensive than the unit is worth so I'll probably just run it until it wont work at all anymore Mine leaks from between the head and cylinder jug and is missing one of the flange bolts on the tube between the high and low pressure cylinders but again, it doesn't seem to be worth the trouble...
I missed an IR type 30 on the list awhile back and have been hoping another one pops up. My tank and motor are good so a new compressor unit would be just fine with me.
Mine is LOUD. An app on my phone says it runs at around 90 dB. Definitely not pleasant to have indoors. I don't know if this is how it is supposed to sound;But it will still pump up to 175, though it takes around 15 minutes to do so on an empty 80 gallon tank. I have since added a pair of franzinators and a magnetic motor starter to it. I used it to sand blast a truck headache rack awhile back and it kept up no problem while running for a couple hours continuously. I would like to take the head off to inspect the reed valves but as indicated above, the parts are way more expensive than the unit is worth so I'll probably just run it until it wont work at all anymore
Mine leaks from between the head and cylinder jug and is missing one of the flange bolts on the tube between the high and low pressure cylinders but again, it doesn't seem to be worth the trouble...I missed an IR type 30 on the list awhile back and have been hoping another one pops up. My tank and motor are good so a new compressor unit would be just fine with me.
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WWheeler
Well-known member
Not sure if a new pump is one of the exempt items or not (it does say 'compressors' but not pumps specificially), but there's currently a 25% coupon out.
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