JUN-AIR Compressor

[BOB BLACKSHAW 1Participant @bobblackshaw1]

Hello,

I have two JUN-AIR compressors from my late fathers shed,Ive checked them out but one has sprung a leak from the air tank. Its a pin hole and a good amount of water came out under pressure. The two compressors which have the drain on top of the tank, why would this be as water will gather at the bottom. My cheap compressor with a thin gauge tank has the drain on the bottom which is the obvious place to put the drain.

My question is what is the best way to repair this pin hole ,I dont have any welding equipment. And how can you drain these compressors with out turning them upside down under pressure

Thanks Bob

[BOB BLACKSHAW 1Participant @bobblackshaw1]

[JasonBModerator @jasonb]

Is there a tube from the drain valve down to the bottom of the tank? Air will push the water up and out and saves fiddling about under the tank

[Clive FosterParticipant @clivefoster55965]

Was this the silent type with a small "pancake" reservoir beneath the compressor unit?

If I recall correctly we had a couple in the lab at RARDE / DERA / DRA with an auto-drain / blow off valve on top that cleared any condensate via an internal tube running from the valve to the lowest point of the tank. As I recall matters it used to go "psssst" when the pressure dropped well below working range after switching off. Presumably the idea was to make the unit maintenance free, just use until worn out.

Clive

[SillyOldDufferModerator @sillyoldduffer]

Regret to say I wouldn't attempt a repair at all – it's a pressure vessel, more than slightly dangerous if the tank gives way due to internal damage. (See discuusion on this forum last year).

The pin hole is almost certainly the deepest flaw in a line of corrosion weakening the entire bottom of the tank and elsewhere. Patching the pin hole won't fix weaknesses caused by corrosion you can't see.

In theory the drain can be at the top because the drill is to open it whilst the tank is still slightly pressurised at close of play. The blast takes most of the moisture with it, and water shouldn't collect in the bottom.

Dave

[BOB BLACKSHAW 1Participant @bobblackshaw1]

Thanks for the replies.

Yes it is the pancake type, very silent and expensive oil, £30 for under half a litre.. I just took the drain valve off and yes there is a plastic pipe but lack of maintenance in the past has left rust in the pipe blocking it up..I think it needs a plate to be welded on the corroded area and a flush out.

Thanks Bob

[BOB BLACKSHAW 1Participant @bobblackshaw1]

Just noticed Dave`s reply, new tank needed.

Bob

[Martin KyteParticipant @martinkyte99762]

Bin it it's not worth repairing. The drain does extent to the bottom of the tank. I've had tanks on JUNAIR compressors 'let go' and the just go PSSSSSST. no drama. Usually along weld lines where the lugs attatch to the frame.

Air compressors are not like steam boilers and dont usually go bang in the smaller sizes.

regards Martin

[BOB BLACKSHAW 1Participant @bobblackshaw1]

Hello all,

On this JUN-AIR compressor any idea what the part on the right is,its not the adjustment for pressure as that is inside the black box that the electric leads are held.

This arrow shows the pin hole, shame as using a pointed tool it feels solid all around the pin hole.

Thanks Bob

[Clive FosterParticipant @clivefoster55965]

Bob

I'd guess the part on the right you refer to is the safety valve. Knob / screw on top to set pressure.

That pinhole looks awfully like a drilled hole to me. Complete with characteristic rise round the edge due to a self tapping screw being bunged in. Rus pinholes are, in my experience, generally rather ragged in appearance.

Folk have been known to put self tapping screws into air tanks to hold cables et al.

I've given up on thinking "No one could be that daft.", regardless of the situation.

Clive

[BOB BLACKSHAW 1Participant @bobblackshaw1]

I put a scriber in the pin hole and wiggled it around that's why the hole is raised Clive.

[noel shelleyParticipant @noelshelley55608]

The tank MUST BE SCRAPPED it can not be repaired ! the item on the right is a safety valve. Noel.

[Author]

Posts