Is Water Trap Filter Faulty?

[Pollys13]

Trap is a, AFG3/8'' Compressed Air Compressor In Line Moisture Water Filter Trap AF3000-03.

"
Air filter adopts novel vane design with high division efficiency and differential pressure discharge device.
This moisture water filter can discharge water automatically.
Used to filter moisture and impurities in compressed air.
With has high filtration accuracy, long service life, safe and reliable.

Water trap filters adjustable pressure is, Pressure adjustment range: 0.05MPa - 0.85MPa,
7.25 psi - 123.28 psi "

If I pressurize the pot to 40 psi, everything works fine.
I also have a low pressure regulator and gauge that is sensive enough to read down to 1 psi.
I want to use 5.5 psi, when I set the regulator to pass air at 5.5 psi I hear air passing through it. The tank is starting to fill up but the water trap is releasing air at the same time.

When get water trap problem sorted out, assume pot will fill up at 5.5 psi albeit, much slower than if was filling at 40 psi?
As I say filling the pot at 40 psi, everything is fine, no air coming out of drain on trap. Though on occassion I think the trap was letting out air at other pressures, though nowhere near as low as 7.25 psi.

This started me thinking the trap might be faulty, then again problem could be caused by trying to run at 5.5 psi as the range of the trap is 7.25 psi - 123.28 psi ? "Also would the pot fill up.... eventually, between 1/2 a pound and two pounds of pressure?

Anyone any ideas?
Thanks.

 

[MoreWellie]

assuming it is fitted with the auto drain option then probably not faulty as it requires 0.1Mpa (just over 14psi) to close the auto drain

https://www.smcpneumatics.com/pdfs/af.pdf

Edit: could you put the filter before the regulator?

 

[daro]

most of the "water traps" I have had on compressors , all do something like you describe - they need a certain amount of pressure to close the drain valve , usually about 10psi
the main problem I have with water traps is some water still getting through

 

[Dcal]

With that sort of regulator you haven’t a chance of regulating to 0.5psi accuracy.
It's just a spring and it (and the gauge) will only give an approximate over the range unless you go for specialist, meaning expensive, calibrated gear.

Can you do a two stage set up where you have a main regulator to take the pressure down to say 15psi and another low pressure regulator getting you the rest of the way?

I don’t know if this sort of gear is available for little money.

 

[Pollys13]

With that sort of regulator you haven’t a chance of regulating to 0.5psi accuracy.
It's just a spring and it (and the gauge) will only give an approximate over the range unless you go for specialist, meaning expensive, calibrated gear.

Can you do a two stage set up where you have a main regulator to take the pressure down to say 15psi and another low pressure regulator getting you the rest of the way?

I don’t know if this sort of gear is available for little money.

" unless you go for specialist, meaning expensive, calibrated gear. " Yes I did get a more specialized regulator was told it would be accurate for what I wanted, not so expensive, about 50 quid."

" Can you do a two stage set up where you have a main regulator to take the pressure down to say 15psi and another low pressure regulator getting you the rest of the way? " That is how I have set up.

 

[Pollys13]

assuming it is fitted with the auto drain option then probably not faulty as it requires 0.1Mpa (just over 14psi) to close the auto drain

https://www.smcpneumatics.com/pdfs/af.pdf

Edit: could you put the filter before the regulator?

Not practical to reposition trap, too much fathing about taking things apart. The way to go I think would be to get a trap with 3/8 ports, with a drain cock not auto drain. Looking at pdf, find a bit hard to fathom. Which would be the correct one to order with a drain cock?
Cheers.

 

[Pollys13]

most of the "water traps" I have had on compressors , all do something like you describe - they need a certain amount of pressure to close the drain valve , usually about 10psi
the main problem I have with water traps is some water still getting through

" they need a certain amount of pressure to close the drain valve " Yes as mentioned, think way to go is get one with a drain cock, not auto drain, assume the drain cock version is manual, closed all the time, just undo to release any moisture.

 

[brightspark]

I just fit a manual tap on the bottom of my water seperators. when im blasting I leave them slightly open after so long you can see the water spurting out of it if I wasn't using my secondary tank for cooling

 

[Pollys13]

I contacted SMC, they came back with, " Please advise the current part number you are using.
The 5.5 psi may not be able to go through the filter also "
I suppose I could always hang a load of washers on the water trap to pull the trap valve down and keep it shut.