Texasmark1
Well-known Member
Have a 4 (real hp), 60 gallon, 230V, air compressor that is roughly 20 years old. Was out of something to do yesterday so I decided to wade into
changing out the pressure control module....had numerous things to get out of the way so that the module could be unscrewed. While installing
my new one, both Square D slightly different Off-Auto lever but otherwise identical, I noticed on the box that it had a mfgr. date of 2004 and knew
that I had it for a long time as a backup.
Installed it and when pressure got to 140 I popped the ckt breakers and started backing the truck up. Spent a lot of time trying to understand
what was wrong and learning just how the mechanism works in sensing pressure, shutting off the power, and bleeding down the head pressure. I
wound up adjusting the larger of the two springs which is the cut off control. I did several iterations of more and less tension and comparing the
length of the spring adjustment to the original while checking the effect on the unit.
In the final analysis, I got it to function properly and the spring was set back where it was initially (1.49") for the cut off pressure specified (125
psig) and the only thing that changed was I lubricated the non electrical conducting metal parts and manually cycled the mechanism.
So, rule of thumb here (to me) is if you have one that has been sitting around for awhile, don't jump the gun and think you have a bad part.....what
you have just might need a little limbering up.
changing out the pressure control module....had numerous things to get out of the way so that the module could be unscrewed. While installing
my new one, both Square D slightly different Off-Auto lever but otherwise identical, I noticed on the box that it had a mfgr. date of 2004 and knew
that I had it for a long time as a backup.
Installed it and when pressure got to 140 I popped the ckt breakers and started backing the truck up. Spent a lot of time trying to understand
what was wrong and learning just how the mechanism works in sensing pressure, shutting off the power, and bleeding down the head pressure. I
wound up adjusting the larger of the two springs which is the cut off control. I did several iterations of more and less tension and comparing the
length of the spring adjustment to the original while checking the effect on the unit.
In the final analysis, I got it to function properly and the spring was set back where it was initially (1.49") for the cut off pressure specified (125
psig) and the only thing that changed was I lubricated the non electrical conducting metal parts and manually cycled the mechanism.
So, rule of thumb here (to me) is if you have one that has been sitting around for awhile, don't jump the gun and think you have a bad part.....what
you have just might need a little limbering up.