Air Compressor Air Release

[bowhuntr311]

I purchased a new 60gallon C-Aire this past weekend and I got it temporarily hooked up until I decided its final place and get everything plumbed.

After the compressor completes its cycle it lets out some air? A friend has a 80gallon big red and his does the same thing so I called him and he claimed its an automatic tank drain. I purchased a separate automatic tank drain that actually attaches to the tank drain on the bottom?

Any imput

Below is a 20second video of it?

 

[akdiesel]

This is not a tank drain you are hearing. Compressors cannot start up under a load in other words the compressor has to be de-pressured every time it starts up. So what it is doing is venting the compressed air out of the compressor and the check valve that goes to your tank with holds the pressure in the tank.
The air you hear is coming from your pressure switch.

 

[4 FN 27]

This is not a tank drain you are hearing. Compressors cannot start up under a load in other words the compressor has to be de-pressured every time it starts up. So what it is doing is venting the compressed air out of the compressor and the check valve that goes to your tank with holds the pressure in the tank.
The air you hear is coming from your pressure switch.

This above is correct.

Did you "run the compressor in"? By that I mean did you run it for a while without letting the tank build pressure? This helps the rings come in and makes sure oil is everywhere it should be in the crank case prior to having a load.

 

[Milton Shaw]

Some of the check valves will have an air release when flow stops if the air release is not in the pressure switch. The ones in the pressure switch have a problem if the power is lost before the switch releases and then comes back on. The compressor in that case will usually trip a house breaker or trip the overload on the compressor as it is trying to start with full load. All compressor have a problem starting against full head pressure even refigs, a/c units and air compressors.

 

[bowhuntr311]

Thanks for the information. Every thing mentioned makes sense.

This above is correct.

Did you "run the compressor in"? By that I mean did you run it for a while without letting the tank build pressure? This helps the rings come in and makes sure oil is everywhere it should be in the crank case prior to having a load.

The owners manual says its not needed because each unit is filled and started at the factory. But I did what you mentioned totally by accident. I got it all hooked up and held down my blow gun nozzle on 1/4 in system just to see if it would build pressure while I was using the blow gun.

 

[4 FN 27]

Thanks for the information. Every thing mentioned makes sense.





The owners manual says its not needed because each unit is filled and started at the factory. But I did what you mentioned totally by accident. I got it all hooked up and held down my blow gun nozzle on 1/4 in system just to see if it would build pressure while I was using the blow gun.

Great. I run in every compressor that way. One of C'Aires techs told me to do that.

He also said a good thing to do is record the charge cycle time from 0 psi to full tank and write that time down on the backside of the compressor. Do the same for the recharge time from the psi where the compressor starts making air to full tank and record that number. Then do this once a year and compare to the original numbers on the back of the tank. This way you can see a problem should one develop with the ring seal or valves. If there is a leaking valve or bad ring the recharge time will be longer.

I have done this with both of my Compressors, the 1997 C'Aire 10 Hp and my 1987 Ingersoll Cast Iron Series 5 HP. Helped me see a problem with the Ingersoll. Had to replace the Head Seal. Charge time from 0-175 took 3 1/2 minutes longer from the day it was new.

You have a nice compressor right there.

 

[Fixin'Stuff]

A friend has a 80gallon big red and his does the same thing so I called him and he claimed its an automatic tank drain.

Makes me wonder how many gallons of water are sitting at the bottom of his 80 gallon tank. Tank drains must be at the bottom of the tank, not up by the compressor.

 

[bowhuntr311]

Makes me wonder how many gallons of water are sitting at the bottom of his 80 gallon tank. Tank drains must be at the bottom of the tank, not up by the compressor.

Exactly what Ive been wondering all day...But I wanna be there so I dont wanna call him and say he is wrong. Maybe I'll stop for a beverage on my way home from work 1 evening this week and record it

 

[JerryB]

The technical name for the valve that relieves the pump pressure to allow easier starting is "unloader valve." Not fitted to all compressors: Just the heavier duty, better quality one. It has nothing to do with draining water from the tank.

 

[gungatim]

The technical name for the valve that relieves the pump pressure to allow easier starting is "unloader valve." Not fitted to all compressors: Just the heavier duty, better quality one. It has nothing to do with draining water from the tank.

What compressors don't use an unloader valve? even the $89 HF units have them. I've never seen a compressor without one...

 

[BearsFan315]

many times the unloader valve is part of the regulator
that is how it is on my condor regulator mounted on the Kobalt i have.

 

[Jim Johnstone]

What compressors don't use an unloader valve? even the $89 HF units have them. I've never seen a compressor without one...

The better compressors use a centrifugal unloader, which is integral into the pump. Other ones use an unloader built into the pressure switch, which drains everything before the check valve.

 

[Schurkey]

Record the charge cycle time from 0 psi to full tank and write that time down on the backside of the compressor. Do the same for the recharge time from the psi where the compressor starts making air to full tank and record that number. Then do this once a year and compare to the original numbers on the back of the tank. This way you can see a problem should one develop with the ring seal or valves. If there is a leaking valve or bad ring the recharge time will be longer.

I really wish I'd been smart enough to think of that.

My compressor is a decade old. I guess "no time like the present" to begin.

 

[redmondjp]

The better compressors use a centrifugal unloader, which is integral into the pump. Other ones use an unloader built into the pressure switch, which drains everything before the check valve.

Or, in the case of my Quincy 325, it uses oil pressure instead of a centrifugal unit to operate the unloader.

 

[Jim Johnstone]

Or, in the case of my Quincy 325, it uses oil pressure instead of a centrifugal unit to operate the unloader.

That's cool. I didn't know that about the quincy pumps.