Air compressor problem

Reply

  #1  
Old 04-28-07, 10:14 PM
C
Member
Thread Starter
Join Date: Nov 2006
Location: San Francisco, CA
Posts: 146
Received 1 Vote on 1 Post
Air compressor problem

I just bought a 2 gallon air compressor that is rated at 2.4SCFM@90psi/3.7SCFM@40psi. It seems to be having trouble inflating a car tire above around 25-30psi.

Example: The compressor indicates that it has pumped itself up to 120 psi. The car tire already has about 25psi and I'd like to pump it up to 32psi. When I press the tire chuck against the tire valve firmly I can hear air hissing inside the tire quickly for about a few seconds, then it slows to zero air transfer in another few seconds. The air gauge on the compressor has dropped by about 20-30psi, and the tire has gained about 3-4psi. I'm sure almost no air was leaked during the process...

As long as the pressure on the air compressor gauge is higher than the pressure in the tire I'm pumping into shouldn't air be traveling into the tire, even if very slowly?

I feel really stupid...
 
  #2  
Old 04-28-07, 11:05 PM
GregH's Avatar
Super Moderator
Join Date: Jan 2001
Location: Manitoba
Posts: 10,181
Received 49 Votes on 46 Posts
Check to make sure that if there is a pressure regulator on the compressor where the air line connects that it is turned to maximum.
 
  #3  
Old 04-28-07, 11:24 PM
C
Member
Thread Starter
Join Date: Nov 2006
Location: San Francisco, CA
Posts: 146
Received 1 Vote on 1 Post
Thanks for the quick response. The regulator valve was twised to the maximum position... How quickly should I expect a compressor like this to pump a car tire from 25 to 35 psi?

Is it possile that a higher quality tire chuck or air hose would help? (I'm currently using the flimsy accessory versions of each that came with the compressor).
 
  #4  
Old 04-29-07, 12:56 AM
M
Member
Join Date: Oct 2003
Location: PA, USA
Posts: 748
Received 0 Votes on 0 Posts
Cruiser, where are you reading the 120 from - is the gauge on the tank or on the regulator? If it's on the tank, then I suspect that the reg is busted. Yours being new, most likely is a manufacturing defect, but it's a common problem on small compressors where the reg is connected right to the tank without a filter. All the dirt and water from the tank end up in the reg and soon you don't have a reg anymore. You may think it's cranked up for full flow, but it may only be letting 30# through. An easy way to check this would be to install a gauge past the reg for a true reading.
 
  #5  
Old 04-29-07, 10:14 AM
Pendragon's Avatar
Member
Join Date: Jul 2002
Location: USA
Posts: 1,851
Received 2 Votes on 2 Posts
Actually, there should already be two gauges, one tells you the tank pressure, the other tells you the regulated pressure.

Perhaps if you gave the make/model or posted a picture?
 
  #6  
Old 04-29-07, 11:15 AM
C
Member
Thread Starter
Join Date: Nov 2006
Location: San Francisco, CA
Posts: 146
Received 1 Vote on 1 Post
It's a Craftsman model 15312. It has two valves, one coming straight off the tank, and another after that for the regulator. The tank indicates 125 when it's charged up, and I can get the regulator to indicate anything up to 125 when it's turned all the way up.

I don't currently have a gauge that I can use to test the pressure coming out of the ports after being regulated, that would tell me if the regulator is flakey.

Also the air hose that comes with it is 1/4", would switching to a 3/8" hose make any difference pressure output-wise?
 
  #7  
Old 04-29-07, 11:34 PM
Pendragon's Avatar
Member
Join Date: Jul 2002
Location: USA
Posts: 1,851
Received 2 Votes on 2 Posts
If you get one of the air chucks that has a built in gauge, that will quickly and easily tell you what your line pressure is. Just press the lever on the chuck without a tire being attached, the gauge should pop out to whatever pressure you have available.

Like this one.. http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=41891

Switching hose sizes will help flow rate for high use devices on long hoses (such as air nailers and die grinders), it won't make a difference for inflating tires and your compressor doesn't put out enough CFM to utilize the larger hose anyway.
 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description: