Carette 300 bar 4500 psi compressor review test - Part2

This is a part2 of the review, goto part1

Adding a PMV to the standard Carette

You can find priority valves or PMV on the internet for less than 100$.
Some Bauer compressors use an OEM PMV which can be found in the US as model 211 priority valve. Just google it. I wasn't able to find it here in Europe.

Some sites where they sell it :
http://www.augustindustries.com/back-pressure-valve-val-back.asp
http://aeroconsystems.com/cart/back-pressure-regulators-priority-valves/model-211-priority-valve-regulator/
http://scubacompressor.com/shop/back-pressure-regulator-p-69.html

A good article on using a PMV in a compressor can be found at http://www.scubaengineer.com/high_pressure_compressor_filtrat.htm

So where do you put in on the Carette compressor? Ideally it should be put after the last filter but it is easier to put just behind the Oil water separator. Since almost all of the water is removed by the Oil water separator with the PMV set at 2000psi, that's just fine.

On the European model (the one I have) the fitting from the Oil-water separator to the filling hose is 1/4 BSPT.
The PMV has a 1/4 NPT fitting.
So you need:

• a 1/4 female barrel BSP (to connect to the BSPT)
• a 1/4 male BSP to male NPT (to connect to the PMV input)
• a 1/4 male NPT plug or 1/4 NPT gauge (to connect to the PMV output1)
• a 1/4 male NPT to male BSP (to connect from the PMV output2 to the bleed)
• a 1/4 female BSP BLEED (to release pressure between the PMV and the tank you are filling)
• a 1/4 male BSP to BSPT (to connect to the standard filling hose which is female BSPT)
• 4 bonded seal washers

All these fittings can be found here in Europe on www.bestfittings.co.uk but should not be difficult to find elsewhere.
FYI the connections on the standard carette filter are metric m10x1.

The end result:

Priority valve fitted to the exit of the oil water separator