150 psi shut off on 175 compressor okay?

[orf]

I want to swap out the stock petcock drain valve with a lever style and found a 1/4 150psi water valve on the shelf. Will it work with my 175 IR Compressor? I see other folks doing this, but maybe there is a higher psi lever valve out there???

 

[DannyG]

Turn the switch down to the 125 psi range. No need to go that high for most common tools. Plus it helps on longevity and on the regulators too.

 

[DannyG]

I think the pressure switch is underneath the auto switch.

 

[usa#1]

Check the exact wording on the valve and do a google search on it. Typically valves are classified according to Class. The amount of pressure they are rated for is based on service temperature and fluid in use. If the valve turns out to be rated for 150psi max design pressure for air, I wouldn't use it as it would be the under the max design pressure of your compressor. Lowes and HD should have a brass ball valve that exceeds the 175 psi compressor for air for under $10 .

 

[orf]

I'lll find a 175. My pressure switch is preset and not adjustable (unless I removed the silicone and dialed it down - anyone done that?). Thought the valve might be rated like tires and be able to handle 25 more PSI. Heard tires that are rated at their max psi by half of what the tested tires blow at. Probably not worth experimenting with though with the valve though

 

[Zrexxer]

Turn the switch down to the 125 psi range. No need to go that high for most common tools.

You don't understand the relationship between pressure and volume. There is no reason whatsoever to disable the advantage of a two stage compressor to accommodate the wrong drain valve.

 

[z28snksknr]

I would continue with your search for a higher rated valve, but I'll offer this piece of info regarding pressure ratings of pipe fittings:

Standard pipe flanges are rated for a "design pressure at a design temperature". For instance, a ANSI 150psi rated pipe flange (the flange is usually the weakest point, not the pipe), is rated for 150 psig AT the pipe material design temperature (>450 °F for most common materials and up over 1200 or so for some alloys) This means that at that high "design" temperature, the pipe and flanges are designed to sustain 150 psig. Consequently, at lower temperatures, the material will be able to withstand higher pressures.

Using 300# class C. Steel flanges as an example, there are industry standards (ASME, ANSI, and ASTM) that state that at 0°C, that class flange can safely withstand (as in normally operate at) up to 740 psig.

Having said all that, a 150# "rated" valve can withstand higher pressures than 150 psig, depending on what the limiting design aspect of the valve is. Again, the design pressure of the valve is AT THE DESIGN TEMPERATURE which usually corresponds to the material's temp vs. yeild strength tendencies.

 

[z28snksknr]

Here is a table for C. Steel flange ratings vs. temp.:

C. Steel Pressure-Temperature Flange Ratings

1000 kPa = 145 psi BTW.


Here is a similar table for pipe for comparison:

C. Steel Pipe Pressure - Temp Ratings

Notice that the pipe is good for over 2800 psig at 100°F while the flanges are rated to roughly 265 psig at 120 °F (for a 150# flange rating) and the pressure rating does not go below 150 psig (1034 kPa) until above 480°F (which is why the 150 psig rating AT 450°F exists to be conservative.)

 

[Charles (in GA)]

Turn the switch down to the 125 psi range. No need to go that high for most common tools. Plus it helps on longevity and on the regulators too.

You don't understand the relationship between pressure and volume. There is no reason whatsoever to disable the advantage of a two stage compressor to accommodate the wrong drain valve.

Agree with Zrexxer 100%. I have a neighbor who (four or five years ago) bought a real nice 2 stage, Quincy I think it was. Poured a pad for it outside, built a nice shed around it, then proceeded to turn the pressure switch down to about 120 psi. He then installed a regulator on the main line coming thru the wall from the compressor. Never could explain to me why he did this other than he felt the compressor would "last longer" and he felt "safer". This is coming from a man in his 70's (retired airline and military pilot, quite intelligent) who has PVC plumbing throughout his shop, he installed in the latter '80s.

Charles

 

[Major Ramifications]

Definitely don't adjust the shutoff pressure. Enjoy the extra capacity that you have paid for. I wouldn't sweat the valve rating at all. There is always a factor of safety built into those ratings.

 

[z28snksknr]

Definitely don't adjust the shutoff pressure. Enjoy the extra capacity that you have paid for. I wouldn't sweat the valve rating at all. There is always a factor of safety built into those ratings.

See my above posts.

 

[DannyG]

I use to think the same, that more psi is better. 175 psi vs 125 psi doesn't change the CFM at 90 psi where regs are set at the end of the pipes. Ever looked at the max psi the of the filters/regulator. They say they're at 150 psi max. Why put more than that in your air lines? Seems theres no choice in this situtation.

I've got a 2 stage IR and theres a nice switch on it thats doesn't affect the volume but offers the option of 2 levels. And I use the 150 psi ball valve for a drain on it too thats anchored to the floor.

175 psi vs setting the compressor switch it at 125 psi is not going to change the volume and cfm when your using less than 100 psi anyways. Am I wrong? Can you guys show what your runnning on your 175 psi setup? Id like to see it.

 

[z28snksknr]

I use to think the same, that more psi is better. 175 psi vs 125 psi doesn't change the CFM at 90 psi where regs are set at the end of the pipes. Ever looked at the max psi the of the filters/regulator. They say they're at 150 psi max. Why put more than that in your air lines? Seems theres no choice in this situtation.

I've got a 2 stage IR and theres a nice switch on it thats doesn't affect the volume but offers the option of 2 levels. And I use the 150 psi ball valve for a drain on it too thats anchored to the floor.

175 psi vs setting the compressor switch it at 125 psi is not going to change the volume and cfm when your using less than 100 psi anyways. Am I wrong? Can you guys show what your runnning on your 175 psi setup? Id like to see it.

Running at 175 psi vs. 150 psi allow for more air to be stored in the tank, so there is increased capacity (usage time) before the compressor has to come on again, allowing the compressor (and the air) to cool more, resulting in dryer air.

 

[orf]

I'd like to see what others are using too since my IR stamped shut off is leaking above about 100 psi. The Home Depot special I got today rated at 150/600 is holding its own so far (for the drain). Looks identical to the Depot one, except it says IR on the plastic lever. I found one at Grainger that was rated for 1000 psi for water and oil (but did not have air or gas on the list).