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Topic: Pneumatic questioon / info ? (Read 779 times) previous topic - next topic

Pneumatic questioon / info ?

While at HWH a few weeks ago, while checking for air leaks, they found the two air regulators up front passenger side were leaking, they took care of the HWH leaks but would not touch any other leaks, no problem..
I ordered the OEM replacements from MOT, and today I installed them, all identical to the OEM units.  Question is What is the pressure setting for the step and for the floor slide ?
Talked  with Keith at MOT, he indicated 60 psi for both, however I find 40 psi on the slide is plenty and 35 for the step seems just fine too.
SO my questions, does anyone have any experience where I should change the psi for either of these ?
Thanks
Dave M

Re: Pneumatic questioon / info ?

Reply #1 –
As I recall, the setting is for how fast they operate, not whether they do or not. At 60 lbs my step slams shut, at 40 it is slow and 50 is just right.
1994 U280, Build 4490
Deming, NM.

Re: Pneumatic questioon / info ?

Reply #2 –
Here's the general rule for setting up air cylinders on any equipment:
1.  The pressure will determine the maximum force (not necessarily speed) the air cylinder will generate - even after it has stopped.  (i.e. cylinder area) X (air pressure)
2.  Then you can slow down the cylinder by using flow control valves  (often needle style valves)

On my coach the flow control valves are located right on the air valves.  Each looks like a set screw sticking out with a jam nut on it.  Turning in= slower, out: faster
There will be two of these: one for each direction of movement
Assuming you liked the speed and performance before, I would leave the flow controls alone and adjust the pressure so it behaves like before.  I've changed mine from any factory setting and now have the pressure at 35 psi - I like a soft close.
John Fitzgerald
1991 U300 (SAI) Side Aisle Island Bed 40'
Detroit 6V92 with Allison Retarder
Meridian (Boise), Idaho
 

Re: Pneumatic questioon / info ?

Reply #3 –
Our step & slide valves are flat and mounted on back-side of step. They have 4 air connections: 1 air cylinder front, 2 air cylinder rear, 3 from air tank, 4 exhaust flow control & filter.

#4 is a cap that controls how fast air exhausts from air cylinder when opening and closing. It also acts a filter to let air out but not let other things in. Turning the cap in slows down air and slows down slide & step and also acts to keep them from slamming in either direction.

A slow operating valves can be made to work ok by taking them apart. Sometimes just removing and cleaning the exhaust port cap will make a poorly functioning valve work fine.

When 12-volts is applied, it puts air into one cylinder port and exhausts the other cylinder port. When 12-volts is removed, the two ports swap to move piston in the opposite direction.