Testmark Air Compressor Not Building Pressure

Reply

  #1  
Old 10-16-18, 05:27 PM
Member
Thread Starter
Join Date: Nov 2010
Location: USA
Posts: 105
Testmark Air Compressor Not Building Pressure

I bought a Testmark 10g air compressor several years ago. The compressor has seen sporadic use through the years, mainly airing up a tire or blowing dust off something occassionally.

I used it to fill my air tank the other day and it wouldn't build above 90psi. I filled it best I could and then turned it off.

I went to use it a couple days later and it wouldn't build pressure at all. It just runs and runs. I have attached a couple photos of the compressor itself and also of a fitting on the side that air is blowing out of. The fitting has a small hole in it and air is coming out of it. (it is pic #3)

Name:  ac1.jpg
Views: 136
Size:  68.3 KB

Name:  ac2.jpg
Views: 85
Size:  60.3 KB

Name:  ac3.jpg
Views: 119
Size:  42.6 KB
 

Last edited by PJmax; 10-16-18 at 05:57 PM. Reason: reoriented pics and labeled part
Sponsored Links
  #2  
Old 10-16-18, 06:16 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 50,954
Likes Received: 154
It's definitely a check valve. I can't tell if it's a combination check valve/pressure relief valve. They are usually separate. I looked thru stacks of check valves and couldn't find that one.

I see many copycat compressors that look just like that one. One is a Craftsman. I left a link for it but that line setup looks a little different.

Craftsman compressor breakdown
 
  #3  
Old 10-16-18, 07:10 PM
Member
Thread Starter
Join Date: Nov 2010
Location: USA
Posts: 105
Thanks for the link. There is a separate pressure relief valve next to the regulators. Iím debating putting a plug where that check valve is long enough to see if it builds pressure. If so, then Iíll know what Part I need to try to find. I noticed on the Craftsman it simply had an elbow at that spot.
 
  #4  
Old 10-17-18, 03:17 PM
Member
Thread Starter
Join Date: Nov 2010
Location: USA
Posts: 105
I did some more looking today.

The part in pic 3 above I suspect is a compression release to let the motor start easier. I took it out and there is a small metal plate that would close the valve when air pressure builds up. (see photos below)

I put in a plug to see whether it would build pressure and it still doesn't. Is there something in the pump that has gone bad? Not sure whether it's worth pursuing trying to repair this compressor or just buy a new one.
 
Attached Images   
  #5  
Old 10-17-18, 06:29 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 50,954
Likes Received: 154
You can't plug off the check valve.
It works by allowing the compressed air to pass thru into the tank but to not come back.

It doesn't just work to keep the air in the tank. The compressor puts out little bursts of air
that pass thru the valve into the tank. Any air coming back will negate any gain.
 
  #6  
Old 10-17-18, 06:44 PM
Member
Thread Starter
Join Date: Nov 2010
Location: USA
Posts: 105
The piece I took out and plugged vents to the outside air. It is not a one way valve into the tank. If you look at pic 3 above you can see the hole where air comes out. It unscrews as can be seen in the fourth and fifth pics. It looks like it should close when the compressor starts pushing air. Seems to be a compression release valve, ie opens when compressor stops allowing the compressor to start up easier and then closes when it starts pushing air. But itís not closing and just leaks air out thus why I put in a plug, to see if it would build pressure. It built up about 10lbs but wouldnít go any higher. Iím thinking something is wrong with the compressor, ie not compressing air properly. Am I off in my thinking?
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
Display Modes