[Roger 1]

Has anyone check into max run time on a Thomson compressor. I am waiting on a new pressure switch and have been running my compressor with the switch inside just to keep air up.

[Richard]

Do you mean the longest you should run it before shutting it off? Or how many hours should the compressor last?

If you are just using the switch on the inside, then shut it off when the supply gauge reaches 100 psi.

Those switches can be bought at any Home Depot or Lowes. Seriously.

[Roger 1]

How much time between cycles. So not to over heat .my square D switch went bad so I buy passed it so when I turn the switch on inside it will stay running.

[Richard]

How much pressure will it build? If it will build pressure, turn it off at 100 psi on your supply gauge.

If it is not building pressure, then you may have misdiagnosed the well pump switch problem.

[Roger 1]

Builds pressure just did not want to over heat the pump. The well pump contacter came apart and was jamb

[Fulltiming]

If your air system is reasonably tight and you are starting from 0 pressure, you should build up to normal engine off system pressure (around 70-90 psi) within 5-7 minutes. I have run my 120 volt air compressor for 10-12 minutes without it overheating when I had a significant air leak. The larger issue is not letting the air compressor run longer than it takes to get the pressure back up to about 90-95 psi. I understand that an unregulated 120 volt compressor can over inflate your air bags.

[Rongripon]

My 115 vac compressor doesn't want to run because the pressure switch doesn't engage. its gotten down to 20 at night and taking a shot in the dark, I'm guessing its freezing. I have never had one do that before..

anyone experience that before. OKC, OK gets cold and of course the seals for the slides deflate be cause the little devil doesn't run unless I manually engage the regulator relay.

[Richard]

Do you have a 12v pump. On some coaches that pump supplies the slide seals also.

[jdkskyking]

This is interesting because I’m noticing the compressor can’t provide enough pressure when the temp drops below 40. Just an observation, no scientific evidence yet. 

Is it possible a pressure switch could be leaking in the cold temperatures?

[Richard]

What is possible and frequently observed is that the push on tubing connections that Newell is fond of using, leak at a much higher rate in colder weather.

As far as the pressure switch leaking, anything is possible.

I would take a very close look at the Newell provided water separator/filter used with the aux compressor. They are prone to porosity.

And of course, the clearances in the pump will be much looser in cold temps, the pump may be approaching it's useful life.

Diagnostics in order. Deadhead the pump against a gauge and see what it's capability is at cold temp before you throw money at a new pump. Then soapy bubbles. Playing with water at freezing temps is always fun.