Moisture trap drain valve issues.

[Somekitt3]

Hey there,

I recently picked up a Jun-Air compressor for ridiculously cheap off gumtree, it was all working fine. I wanted to filter the air so I fitted a moisture trap between the compressor and the receiver and then another one coming off the receiver.

The problem is that air literally constantly leaks out of the drain valve for the moisture trap bowl... Like I have no idea what you're supposed to do about that. It doesn't seem to be a fault because both of the traps I bought do exactly that. when you pull down the valve it stops leaking and the compressor builds pressure and works normally again but that seems to be the exact opposite of what it's meant to do.

My understanding was that you pulled down the drain valve to drain the oil and by default it held it in - that seems to be what the manual says. For my one it seems to drain all the oil and air by default and needs you to pull it down in order for it to hold any pressure.

It's one of these silverline ones: http://www.silverlinetools.com/en-GB/Products/Air Tools/Air Fittings/427596 It has one of those valves that's pretty standard on all of the Chinese made moisture traps so I was wondering if anyone had experience with how these are supposed to work.

 

[AndreZA]

That bleed valve is pushed close with air pressure. If it stays open it means there is not enough pressure. Try and fit a bowl with a tap instead.

 

[Somekitt3]

Ah, well that's annoying. I'm thinking the reason there's no pressure is because I put it before the check valve. I'm also thinking simply stopping the hole with a plug or something would serve the same function as a tap, or would that be unsafe? I could just take the bowl off for cleaning it out and emptying it which is a pretty simple process. All the taps I've found that fit this thread seem to cost more than the trap itself... Which isn't ideal.

 

[Malky]

Ah, well that's annoying. I'm thinking the reason there's no pressure is because I put it before the check valve. I'm also thinking simply stopping the hole with a plug or something would serve the same function as a tap, or would that be unsafe? I could just take the bowl off for cleaning it out and emptying it which is a pretty simple process. All the taps I've found that fit this thread seem to cost more than the trap itself... Which isn't ideal.

Block it and just unscrew the whole bowl like you said, as long you release the pressure before doing so it won't be a problem, but while you have the bowl off have a look to see if spring in that valve is either jammed or damaged, maybe even weak through age, it should really close itself as soon as pressure starts to build up, so basically as soon as you turn on the compressor, could even be a little debris blocking the spring or the valve.

 

[Somekitt3]

Block it and just unscrew the whole bowl like you said, as long you release the pressure before doing so it won't be a problem, but while you have the bowl off have a look to see if spring in that valve is either jammed or damaged, maybe even weak through age, it should really close itself as soon as pressure starts to build up, so basically as soon as you turn on the compressor, could even be a little debris blocking the spring or the valve.

As far as I can tell the spring valve is working as it's intended to because I swapped it out with the other valve from the other trap and it did the same thing. I would think maybe there could be a problem with the regulator leaking air or something but it holds it fine when I hold the valve down. I guess they either ship all these things out with faulty valves, or just build the valves so that they only activate under very high pressure... Which seems silly because you don't want to vent all the air every time your compressor is operating on low pressure.

Problematically I've realised I have no way to vent the pressure in the trap without a tap so I suppose I'll have to invest in one. Ah well.

 

[AndreZA]

Those valve are suppose to work like you are experiencing. Air will push it close from the inside, no need to pull it manually. Like I said, if the pressure is too low, it can not be pushed closed. It does this so that it basically drains automatically. You can force it by pressing the button while the tank is full.

The pressure between the motor and tank is not enough to keep that valve shut. The pressure build up in the tank. It is not meant to be in that position. I don't even know if the filter inside that trap will work with oil.

 

[jord001]

Hey there,

I recently picked up a Jun-Air compressor for ridiculously cheap off gumtree, it was all working fine. I wanted to filter the air so I fitted a moisture trap between the compressor and the receiver and then another one coming off the receiver.

The problem is that air literally constantly leaks out of the drain valve for the moisture trap bowl... Like I have no idea what you're supposed to do about that. It doesn't seem to be a fault because both of the traps I bought do exactly that. when you pull down the valve it stops leaking and the compressor builds pressure and works normally again but that seems to be the exact opposite of what it's meant to do.

My understanding was that you pulled down the drain valve to drain the oil and by default it held it in - that seems to be what the manual says. For my one it seems to drain all the oil and air by default and needs you to pull it down in order for it to hold any pressure.

It's one of these silverline ones: http://www.silverlinetools.com/en-GB/Products/Air Tools/Air Fittings/427596 It has one of those valves that's pretty standard on all of the Chinese made moisture traps so I was wondering if anyone had experience with how these are supposed to work.

If it's any consolation, My air trap is exactly the same on my Sim-Air silent compressor. I have to switch on and just pull the valve down or the air just comes out of it, otherwise it works fine. It may be some sort of design fault. My compressor does not have a pressure shut off so is constantly running and has a tiny spring loaded bleed valve. Maybe thats the reason.

Lee