Home Compressor guru's

Our home air compressor hasn't been working for about a year - procrastination at its best here.

I did my tire rotation today without the air tools .... So I thought it's about time to really start investigating this and get it fixed.

It's a 30 gallon Dayton Cast Iron series model # 4B234. If you want/need more info - I can look for it.

In a nutshell (from what I remember)- the pump doesn't stop pumping. The tank will have about 80psi in it (should be closer to 125psi). At that point - the pressure in the tank doesn't increase but it bleeds off instead. The copper tubing that carries the air into the tank gets scorching hot. The air that's bleeding off (or leaking) is around the backside/underside of the pump. We haven't been able to locate the exact location of the leak, it's hard to find (you can hear it ...).

My husband removed the head and inspected everything in there. Took it to work to have someone else (with more experience) look at it. They both agreed nothing looked wrong.

The head is still off the compressor - my husband needs to put that back on before we can crank it up again and do further troubleshooting. I called and talked to Grainger and got some neat info - but, it was all kinda 'overwhelming' without having someone point to where all these things were on the compressor itself. I wish I had some diagrams too....

Any thoughts?

 

Put it back together and run it. When it starts to leak, spray soapy water in the area. Bubbles where tell you exactly where the leak it. A repair plan can be figured out from that.

Good luck

 

It's more than just a slight leak.... It's blowing pretty hard that you can hear it. It's a matter of finding it and 'feeling' the leak.

But yeah, need to get it put back together first to do some further troubleshooting. <poking my husband >

 

Is it leaking when the motor isn't running AND when the motor is running or is it one not the other? My guess is that it's the check valve not closing when it should.

 

It sounds like my compressor! !! I don't have the same brand that you do but sometimes (especially when the weather is cold) when I start it up it will get to about 80 psi and the safety valve will pop open and the comperssor keeps running! ! !!!!

 

I used to actually sell compressors. My guess is that the pressure relief valve is bad or stuck, which tends to happen when they corrode. These are often located next to the pump with a ring for removing pressure manually or on the drain plug. Give the ring a couple of jerks and see if it moves. Otherwise, could simply be a leak in one of the fittings. If it is actually under the tank, then the pressure relief valve there could be corroded pretty bad from collected condensation. If there is in fact a rusted through spot, you might want to consider a new compressor because that means the tank must be rusted pretty bad, and you don't want one of these suckers exploding. Good luck!

 

Awesome gang!
I'll run downstairs tomorrow and look things over more closely (although, its still apart at the head).

 

The entire unit


The pistons (I have no idea where the head is...again, my husband has it somewhere). The pistons & walls looks pretty darn good - but whatta I know?


Here's where the valves & such are:


The gauge on the left is what we installed. I'm assuming that's to regulate the outgoing airflow.

If someone could school me on the other items ....
The silver looking component attached directly to the tank with a gauge hanging off of it.... The gauge measures tank pressure? What's inside the silver 'thing'?

The brass item attached to the black box. That looks like a pressure relief (I'm guessing). There's a plastic air line that goes from the top of that thing over to the bottom of the inlet (copper) tube. I'm not sure what it's supposed to look like - at the bottom of this brass thing, is a little nub that sticks downward (with what appears like a rubber o-ring on the bottom). I can push this up & down. Is this normal? or is this thing stuck OPEN or something? (the leaking air wasn't coming out from the bottom of this, so not sure if this has anything to do with it or not?)
Again, I'm guessing....
If anyone has any insite - that'd be great!!
Thanks soooo much!

 

The black box is a pressure switch. The regulator attached to it with the dial is what you set the pressure at. When the pressure in the tank reaches that setting, the motor shuts off. If this thing has a pressure relief valve, its either on the bottom of the tank. Its sometimes the drain plug itself. If you look at this url:
http://www.generalairproducts.com/accessories2.htm#Relief

click on the 4th image from the left, bottom. That's what these look like.

Some of them are located near the pressure switch. Check out this thread:

http://www.pirate4x4.com/forum/showthread.php?p=9349578

That shows you what other pressure relief valves look like.

Anyhow, I'd put it back together and find out for sure where it is actually leaking, pinpoint where the air is coming from, then go from there. As it is now, its impossible to do that since it is all apart. Anyway, be careful and good luck!

 

I need to buy one of these soon....

 

If you buy one, stay away from the units that are "oil-free", or have teflon cylinders. Those suckers burn out pretty quick. Also- get more capacity than you need. The more CFM's, the mower tools you can use. Air wrenches use a LOT of air. The higher the capacity, the less the motor and compressor have to work.

 

Thanks - and we definately have to put things back together.

The only other thing attached to the tank is at the bottom - looks like a drain cock


Do you have any idea what that brass thing (on black box) is or does? How does that work?

Another question - the gauge that's reading the tank pressure, could that be faulty? Where.... the gauge reads low and continually tells the compressor to keep pumping yet the actual pressure in the tank is enough to cause it to bleed off?
I guess installing a new gauge would be easy enough just to elminate that (or not).

 

I'm thinking of a 60 gallon vertical unit on wheels like my father has... that thing is nice...

 

Too long..maybe 4 months.

 

Thanks Gang!
It's finally working now and didn't cost us a penny.

The darn compressor has this huge hard plastic guard on it that inhibitied us from feeling where the leak was actually coming from originally. Stupid thing - we cut the damn thing off completely.

After doing that & getting the head back on - got it pumping and (embarrassing) found the leak almost immediately. The nylon hose that goes into the copper inlet was leaking at the quick disconnect. Pulled the hose out, cut about 1/2" off the end and .....fixed.

We were expecting to have to replace the entire regulator assembly or something more than that. Gotta love those easy fixes.

 

Good deal on the quick fix, and the copper tube being hot='s normal, compressing a gas is going to build up heat, just like on your Tacoma Motor(Exhaust) expanding gas ='s cold, think (refridgeration). Just make sure you drain the pet cock (he he) often to prevent rust in the tank. The little black box has adjustments (pressure switch) which tells the compressor motor to stop at a set P.S.I. I had to jack mine up to run an impact or sand blaster. My compressor is a Champion 60 gallon 2 cyl with a 2 hp motor, not good for air tools but one at a time it can deal with the demand. Just don't exceed the tanks recomended max psi.

 

I actually got this one from a Bakery, it was used to power their hopper which squirted the muffin mix into a muffin pan, three years old, for $50.00, new it was almost $950.00