Is my pressure maintaining valve broken?

[ATJ]

I have a Poseidon PE-100 compressor. I've had it for around 3.5 years and have not had any issues at all with it.

The way I normally turn it on is with the drain valves open and the fill valve open. Once it starts, I close the drain valves but leave the fill valve open. Initially no air comes out of the fill valve until enough pressure builds up in the PMV and then it bursts out, stops, bursts out, etc. I usually leave it a minute in case there was any CO build up.

Last Friday I changed the filter and went to use the compressor this morning and right from turning it on, I get a slow flow of air through the fill valve. It then builds up, does a big burst but then there is a constant flow.

Am I right in assuming something has gone wrong with the PMV or is there an another explanation for what I am seeing.

I am reluctant to fill any tanks as without the PMV working properly, there will be a lot more moisture in air going through the filter.

 

[Mudbags]

Sounds like a leaking PMV. It's not a big issue but will likely get worse over time.

Contact your local dealer and ask for a maintenance kit or a new PMV. Part number is 122810.

Good job bleeding the system for a minute on startup too - a lot of operators don't do that, which just puts the built up CO2 from the filter and hose straight into their first cylinder.

 

[ATJ]

Thanks for the confirmation.

I've already contacted Bauer Australia and they have the part (it is actually PN 126153) in stock. It's $400 but that's better than having to replace a bunch of rusty tanks.

 

[happy-diver]

What a rort, what's in there man, couldn't you kludge it

 

[clownfishsydney]

Andrew, my Junior II does not fill like you describe, it starts slow then air comes out in one constant stream. I assume that the PE-100 should do the same. Have you removed the valve and looked at it? I would do that first.

Here is a link to the parts manual https://ase.net.au/wp-content/uploads/2018/03/PE100-Parts-List-January-2010.pdf

 

[ATJ]

Andrew, my Junior II does not fill like you describe, it starts slow then air comes out in one constant stream. I assume that the PE-100 should do the same. Have you removed the valve and looked at it? I would do that first.

Michael, Are you talking about how yours works with load (i.e. connected to a tank) or with no load?

With no load, it should work exactly as I described as that is the PMV doing its thing. The idea of the PMV is to ensure that the pressure of the air going through the filter is at least some preset (usually around 150bar). This does the heavy lifting of moisture removal.

Basically what happens with no load is no air will come out until the pressure inside the system hits 150bar (takes around 30 seconds), then the PMV opens, the air is dumped and the PMV closes again.

With load, it is not as obvious to see but you won't notice the gauge move initially and then, yes, it will be one constant stream.

I have removed the valve and it looks perfectly fine. There's nothing that can be serviced other than adjusting the required pressure which I am reluctant to do. Although, as it looks like I need to replace it, I did have a go but will have to put the valve in a vice. I figured there might be some debris that somehow got introduced after I changed the filter and adjusting the pressure might dislodge it. I doubt that there's any debris as I'm very careful changing the filter material and I'd think 150bar would be enough to dislodge it anyway.

This is a great article describing the PMV: Compressor Filter System Theory - Scuba Engineer

 

[-JD-]

Does anybody resell the AquaEnviroment PMVs down there? Standard Flow Back Pressure Regulators (Priority Valves) On Aqua Environment Co., Inc.

They are < US$100 here and rebuildable.

 

[ATJ]

Does anybody resell the AquaEnviroment PMVs down there? Standard Flow Back Pressure Regulators (Priority Valves) On Aqua Environment Co., Inc.

The Bauers are German and almost certainly metric and the whip swivels around the PMV. To make one of them work, it would need a bunch of other adapters, which will take time and extra cost. Sure it may be less that the A$400 but I won't have tanks for the weekend.

 

[clownfishsydney]

Michael, Are you talking about how yours works with load (i.e. connected to a tank) or with no load?

With no load, it should work exactly as I described as that is the PMV doing its thing. The idea of the PMV is to ensure that the pressure of the air going through the filter is at least some preset (usually around 150bar). This does the heavy lifting of moisture removal.

Basically what happens with no load is no air will come out until the pressure inside the system hits 150bar (takes around 30 seconds), then the PMV opens, the air is dumped and the PMV closes again.

With load, it is not as obvious to see but you won't notice the gauge move initially and then, yes, it will be one constant stream.

I have removed the valve and it looks perfectly fine. There's nothing that can be serviced other than adjusting the required pressure which I am reluctant to do. Although, as it looks like I need to replace it, I did have a go but will have to put the valve in a vice. I figured there might be some debris that somehow got introduced after I changed the filter and adjusting the pressure might dislodge it. I doubt that there's any debris as I'm very careful changing the filter material and I'd think 150bar would be enough to dislodge it anyway.

This is a great article describing the PMV: Compressor Filter System Theory - Scuba Engineer

Andrew, my Bauer Junior II does not work like yours does, with or without load. The air comes out consistently once it hits the set pressure. Have you tried blow air in a reverse direction?

 

[ATJ]

Andrew, my Bauer Junior II does not work like yours does, with or without load. The air comes out consistently once it hits the set pressure.

Michael, I'd be concerned that your PMV is not working correctly.

From the Junior II manual

4.4.5. PRESSURE MAINTAINING VALVE

DESCRIPTION

A pressure maintaining valve is mounted at the outlet of the filter system P21. It ensures that pressure is built up in the filter even from the start of delivery, thus achieving a constant, optimum filtration. It will also guarantee proper working conditions for the final stage cylinder. The pressure maintaining valve is adjusted to 150 +/-10 bar (2,175 psi).

It would take some time to build up the pressure to 150bar so there should be no flow at all until it reaches 150bar.

By the way, Cody's PE-100 works exactly as mine (used to).

Have you tried blow air in a reverse direction?

I have but given the PMV works at 150bar, that's no easy way for me to blow >150bar back through the valve.