compressor pressure reset

[Ruperto Mendiones]

I have a Ingersoll Rand ~ 2 hp hp 80 gal tank air compressor. The setpoints are 120 psi shutoff and 80 psi turn on. Unfortunately my motorhome tires need 100 psi. When I can't get air into a tire I have to bleed the system until the motor turns on and pumps up enough pressure to inflate the tire. (repeat x 6 tires) I think the compressor has an unloader valve allowing it to get to speed without load.

What adverse events would occur if I reset the cut-on pressure to 100? Also could I safely push the cutoff point to 125 psi?

[Mike Cutler]

You would be "short cycling" the compressor. Not a good thing to do on a continuous basis ,unless it is designed that way.
It could be that the 80/120 is the number(s) IR arrived at to just cut down on the duty cycle, and extends the life. It's your compressor, make it do what you need it to do.
I wouldn't increase the shutoff pressure though. 5psi, multliplied by the surface area of the tank, is a lot of extra energy. IR would have to tell you if the tank is rated for that. You may even run into the tank mechanical relief.
2HP for an 80 gallon tank seems a little "anemic" to me. I would have expected 5 HP??? That 2HP has to be running for quite awhile to initially bring that tank up to pressure.

[Ruperto Mendiones]

An alternate means would be to buy a tank of nitrogen to inflate the tires. Until I got the motorhome, the compressor serviced all my needs easily.

[Jeff Body]

Have you double checked the manual for the compressor specs? That seems really low to start at 80psi for an 80 gallon tank. Most tools are rated at 90psi. So for it to kick on at 80 seems low. Maybe the pressure switch is going bad.

[Jerome Stanek]

You should be able to adjust the switch to come on a little higher. most larger compressors come on at 100 PSI or higher. mine kicks on at 150 and off at 175 but it is a 2 stage unit

[Ron Selzer]

I have a Ingersoll Rand ~ 2 hp hp 80 gal tank air compressor. The setpoints are 120 psi shutoff and 80 psi turn on. Unfortunately my motorhome tires need 100 psi. When I can't get air into a tire I have to bleed the system until the motor turns on and pumps up enough pressure to inflate the tire. (repeat x 6 tires) I think the compressor has an unloader valve allowing it to get to speed without load.

What adverse events would occur if I reset the cut-on pressure to 100? Also could I safely push the cutoff point to 125 psi?

I would turn the low end up and put up with the short cycling, as to the high end good chance you will trigger the safety pop off valve

[Richard Coers]

I doubt if anyone on here can vouch for exceeding the safety factor designed in by the original engineers. They are the only ones that know the material and testing data. Exceeding a set point in a pressure vessel could result in a horrible result, even fatal result.

[Tom M King]

I did that for one of my compressors, to run nailguns, and it hasn't quit working yet. I have it set to come on at 105, and off at 125. That one did come with a 125 kick off point anyway, but it wouldn't scare me much if I turned it up a little.

[Bruce Page]

Adjusting the cut-in pressure is not difficult to do, Google it. For safety reasons I would not mess with the cut-off pressure side. My 2hp/30gal IR cycles on at 90psi and off at 130psi.

[Bill Dufour]

Most home owner swiches are a preset pressure differential. If you raise the low end pressure you raise the high end the same amount.
You could plumb in two switches and toggle the power through one or the other depending on needing higher output or not.
Bill D

[Rich Aldrich]

Typically the pressure relief valve is what protects the compressor and tank from over pressure and resulting rupture. The high set point isn’t what protects the compressor. Raising the set point might cause the relief valve to pop. Consult you manual but also check the name plate. It normally gives you the maximum pressure that the system can handle. You can raise the start pressure set point, short cycle the compressor for just this job and then lower the low pressure set point when you are done airing up these tires.

[Doug Dawson]

I have a Ingersoll Rand ~ 2 hp hp 80 gal tank air compressor. The setpoints are 120 psi shutoff and 80 psi turn on. Unfortunately my motorhome tires need 100 psi. When I can't get air into a tire I have to bleed the system until the motor turns on and pumps up enough pressure to inflate the tire. (repeat x 6 tires) I think the compressor has an unloader valve allowing it to get to speed without load.

What adverse events would occur if I reset the cut-on pressure to 100? Also could I safely push the cutoff point to 125 psi?

I don't understand some of the subleties that you are referring to, but if it were me, I'd just pump up those tires and call it a day. I have that compressor too, la la la. What is the actual issue?

[Bruce Page]

I don't understand some of the subleties that you are referring to, but if it were me, I'd just pump up those tires and call it a day. I have that compressor too, la la la. What is the actual issue?

Doug, if he fills one tire to the required 100 psi and the pressure in his tank drops to 95 psi, he can’t fill the next tire unless he bleeds the tank back down to 80 psi and compressor pumps back up. Essentially, he’s wasting 15 psi and the energy it took to generate it, each time.

[Steve Fish]

Doug, if he fills one tire to the required 100 psi and the pressure in his tank drops to 95 psi, he can’t fill the next tire unless he bleeds the tank back down to 80 psi and compressor pumps back up. Essentially, he’s wasting 15 psi and the energy it took to generate it, each time.

So either way he’s going to cycle the compressor a little more to get the tires filled. I’d just up the cut-in as already mentioned. If it’s a Square D switch or similar it probably has adjustment instructions on the back of the cover.

Sometimes it’s easier to get the tires inflated if you get the weight off em with a jack

[Jason Roehl]

Sometimes it’s easier to get the tires inflated if you get the weight off em with a jack

Absolutely false. The air pressure in the tire does not change whether it's loaded or unloaded. The weight that a wheel is bearing only affects the size of the contact patch of that wheel, due to tire deformation. If one of his motorhome wheels is bearing 2000 lbs, and it's at 80 PSI, then there's 25 sq. in. of tire on the ground. If he bumps that pressure up to 100 PSI, then there's 20 sq. in. of tire on the ground. The air pressure doesn't care what the loading of the tire is, nor what shape it is. The only thing that would make a tire easier to fill is a much higher supply pressure than what's in the tire.

[Steve Fish]

I stand corrected sir. I got distracted the middle of my response and when I came back to finish I was thinking about a different situation for some reason. Something about the tire not being set on the rim Apologies for my misinformation

[Doug Dawson]

Doug, if he fills one tire to the required 100 psi and the pressure in his tank drops to 95 psi, he can’t fill the next tire unless he bleeds the tank back down to 80 psi and compressor pumps back up. Essentially, he’s wasting 15 psi and the energy it took to generate it, each time.

I was spraying all day yesterday and the fumes must have been getting to me. :^) Back 20 years ago when I got my IR compressor, all the 80 gallon tanks were two-stage, and they sat at 175 psi. It sounds like things have changed.

[Tom M King]

No shortage of 2-stage's these days.

[John K Jordan]

An alternate means would be to buy a tank of nitrogen to inflate the tires. Until I got the motorhome, the compressor serviced all my needs easily.

You might need a pretty big nitrogen tank. Typical pressure in a tank is 2000 psi but the volume is not huge - just about 80 cu ft in a "Q" tank, the largest you can own AFAIK. You can lease larger tanks. But the pressure will go down quickly with use. Maybe OK for topping off? But if you buy a tank you need to buy a regulator and hose and fittings too, can get expensive.

I have truck and trailer tires that need 90 psi and sometimes I also wish the turn-on pressure were a bit higher - I think mine is set to come on at about 85 psi. I use an IR 5hp two stage 60 gal compressor.

What about one like this for topping off tires: https://www.amazon.com/GSPSCN-Portable-Cylinders-Compressor-Inflatables/dp/B07VVC1JHD I've used a smaller one on a truck tire and it worked OK but wasn't real fast.

JKJ