We are using the Norgren 16-004-011 pressure relief valve on our pneumatics system this year (we have several of these in our pneumatics parts bin). I was looking for a price for this valve and it does not appear to be available on Andymark any more.
They have switched to a new type of pressure relief valve, am-3871.
This is not one of the listed “recommended” PRVs listed in the blue box in the game manual (although it is close to the McMaster Carr 48435K71).
It looks like the new PRV has a pull ring to be able to also serve as a dump valve.
Does anyone have any experience with this new am-3871 valve?
In particular, one of the annoying aspects of the old style PRV is adjusting the relief setting to be high enough that the pressure switch shuts the compressor off before you start venting air (so the compressor is not running continuously, but low enough to be legal. It seems like the old style PRV has a bit of a range where is starts to leak and you have to keep raising the pressure before it vents fast enough to stabilize the pressure. This range between just starting to leak and stabilized leak rate is just barely narrow enough to satisfy both constraints. And then changes in temperature can cause this to shift so that your compressor is turning on periodically even though you are not using any air (and you don’t have a leak).
Does the new PRV have a better range of adjustment?
(by the way, I would have included links to those items, but I have not figured out how to embed links in the “new” CD yet. I’ll work on figuring that out before too long)
The old valves should just start to vent at 125 psi. They should be closed by 120psi. If your compressor was running full time you have it set way, way, way to low.
I would prefer the old Norgren valve over the pull tab style. The upside of the pull tab style is that you can get a new one most anywhere air compressors are sold.
No. McMaster Carr 48435K71 and AndyMark am-3871 valves (and Kingston KSV12, and Control Devices ST12, and perhaps others) are factory adjusted and not intended to be reset by the end user. These valves are highly recommended over that thing we used to use.
This is not the case. If you had a boiler or pressure system, you or your code inspector would use the “lifting lever” to test the operation of the installed valve.
We have been able to adjust the old style valves so that the compressor is not running full time. But it does seem to leak a little at 120 psi even though it is set to vent at 125 psi. So the compressor will kick in every once in a while.
It seems like the adjustment can change with temperature or possibly altitude. We had it well adjusted in our build space and we had an inspector question it at an event as he felt the setting was too high. Needless to say it is annoying. We have our robot built at this point (and in the bag) so we probably won’t change it for this year, but I will look into the new style PRV for the future as it sounds a lot less troublesome.