[Mib2nd]

While searching for air leaks I found that my 120V compressor is hot to the touch. I understand it may get warm if running frequently, but it runs about once every half hour and I have found the leaks and in the process of fixing them. The top of the manifold is just over 120 and the housing near the coils is over 200 consistently.

I do hear a humming prior to the pump coming on for a few seconds and an occasional humming and the compressor not coming on. I did order a new capacitor thinking maybe it may be the cause. For $12 its worth a shot.

Any one have any ideas or experience with this? These pumps are not cheap.

[Richard]

I think you are on the right track. Some voltmeters have the ability to test the caps.

The second thing you want to confirm is that there is a pressure relief system of some sort to relieve pressure on the pump when it starts. If you don’t have such a system, the pump tries to start against head pressure and that is no bueno. Many owners have removed the original system because it is/was a notorious leak.

[Mib2nd]

I think you are on the right track. Some voltmeters have the ability to test the caps.

The second thing you want to confirm is that there is a pressure relief system of some sort to relieve pressure on the pump when it starts. If you don’t have such a system, the pump tries to start against head pressure and that is no bueno. Many owners have removed the original system because it is/was a notorious leak.

It does not appear to have any kind of pressure relief on it.

[Richard]

You really need one. I use a very simple approach as outlined in post 45. http://newellgurus.com/showthread.php?tid=3609&page=5

[HoosierDaddy]

   
This is what I used

[Mib2nd]

This is what I used

It does have a pressure regulator. I thought you were referring to something else that was a pressure relief valve.

[HoosierDaddy]

This is what I used

My illustration is not a pressure regulator. It is an on/off switch for the air compressor. It also bleeds the air pressure from the compressor head at shut down . This model starts compressor at 95 psi and shuts off at 125 psi. Eliminating that head pressure greatly aids the compressor when it starts the next time. 

It does have a pressure regulator. I thought you were referring to something else that was a pressure relief valve.

[HoosierDaddy]

   
I’ve circled the pressure relief valve that resides inside of the pressure switch.

[Richard]

Jim, those devices are BOTH pressure regulator and pressure relief. They are extremely common on air compressors. In your case, if you decide to go this direction, the device would replace your pressure switch.

When the pressure reaches cutoff, the relays mechanically open, and at the same time an arm attached to the relays activates a simple valve that opens the line attached to it to atmosphere.

Newell used a system with an electrically actuated solenoid that drained the bottom of a water separator bowl. Fantastic in theory. The problem is the bowl on the separator is made of polycarbonate and eventually cracks and leaks badly.