Abac Compressor Please Help

[Mitchelld]

i have the 200L 3 HP model,

problem is, i have an air leak from where the on off switch is below the black plastic box, anyone any ideas?
http://www.airsupplies.co.uk/media/...essor_3_hp_200_litre_15_cfm_-_three_phase.jpg


seams to be from where the pipe enters this casing thatair is leaking, any advice appreciated folks.

 

[rtbcomp]

Does it stop when the pump stops, if so could be faulty unloading valve.

If it carries on until the tank is empty then

a) if it stops when you disconnect from the mains and set the switch* to "on" it's probably the non-return valve.

or b) if it carries on with the switch* set to "on" it could be a punctured diaphragm.

* by switch I mean the button on the pressure switch (black plastic box).

 

[Premiershipman]

I had a quick chat with my supplier who is getting me the 150Litre version of this unit, he says that the check valve is probably knackered.

He says to empty the cylinder and then follow the pipework from the on/off down to where there is a brass valve with 3/4 hexagon nut - he says if you take that off there is an assembly inside that maybe missing or worn.

This was a quick phone conversation so may not have caught all of the info but it may give you a headstart.

http://www.abac-support.co.uk/troubleshooting.htm

Check Valve (1312100170) by ABAC, - If your pressure switch is leaking at the unloader valve, replace this part.

Hope this helps.

Shady

 

[Mitchelld]

Cheers guys I will check those solutions out, this may shed furthe light, it wasn't building up pressure n found it to be worn gasket, replaced these and pressurre wasn't an issue, although when the tank built upto around 150 Psi it didn't cut out as I understand it should have, and it then developed a leak as stated above?

 

[rtbcomp]

Could be the switch is faulty or wrongly set. The high pressure may have damaged the diaphragm.

There's some diagrams of compressor bits in my photo album that might help explain how it all works.

Slackening the spring in the pressure switch will reduce the cut-off pressure.

Is there a safety valve fitted to the pressure switch? If so it could be this blowing off because of the high pressure.

 

[Mikey D]

we had issues with theses abac compressors from new , with no pressure in the reciever ,the compressor would run but not build pressure . Air would leak out of the pressure switch .
After about 5 or 10 mins it would start to build pressure and work fine

so if its a new unit let it run for ten mins

cheers Mike

 

[rtbcomp]

That could be because with an empty tank it takes time for enough pressure to build up to close the unloading valve. This is deliberate as these valves close at about 20psi to allow enough time for the motor to get up to speed before they come under load.

 

[Country Joe]

Not much help to you, but...

Confession time!
When I got my first decent compressor (ie one with a receiver) it never filled up to the point where it would switch off - just seemed to run & run.
Turned out that the drain plug wasn't screwed in, at the bottom of the receiver!

Didn't even work it out by myself, ended up ringing the supplier. Never once did he laugh, or even use the word "idiot"!
All the Best,
CJ

PS - It's also a 3hp Abac

 

[Mitchelld]

as im unsure what a lot of the parts are actually named , ive took some photos and il describe from there where the leak is coming from

seams to be leaking out the hole in the side of this fitting, any ideas

 

[rtbcomp]

That's the unloading valve.

Does air keep coming out once the pump has stopped? If so cleaning or replacing the non-return valve (aka check valve) should do the trick.

 

[Mitchelld]

yes air keeps coming out, which is the non return valve ? lol

 

[rtbcomp]

Did you have a look in my albums?

http://www.mig-welding.co.uk/forum/album.php?albumid=900

 

[Mitchelld]

i shal check that valve later and report my findings! thanks again

 

[rtbcomp]

Make sure there's no air in the tank before you undo any nuts

 

[Mitchelld]

is the check valve just the piece at end of black pipe? or the whole brass assembly thats screwed into the tank ???

it builds to about 50 psi no more and even when switched off at the mains still hisses air.

i would like to understand how the unloading valve works and how any air coming through the pipe wouldnt come out that little hole on the side ??


sorry for sounding stupid and probably frustrating yous

 

[Mitchelld]

looked through your photos again RTBCOMP, i understand the non return valve now,

although i dont understand how air wouldnt come out the unloading valve, how does it close off that hole ?

 

[tigler]

When the compressor stops the pressure in the receiver forces the non-return / unloader valve closed thus preventing air escaping. At the same time, the valve opens the hole to allow air to escape from the delivery pipe from the compressor, but reamins closed against receiver pressure. This 'unloads' the delivery pipe of pressure so the compressor can start without forcing against pressure.

 

[rtbcomp]

The hole is closed by pressure build up and with the switch in the "on" position.

When cut-off pressure is reached (or the knob on the black box is set to "off") the unloading valve is forced open (by a plunger on the switch) to empty the delivery pipe, this is the short hiss you can hear when it's working properly. This is necessary so that the motor restarts with no load on it.

Under normal conditions you only get a short hiss because the non-return valve (NRV) stops air feeding from the tank into the delivery pipe. A faulty NRV will allow air into the delivery tube and out through the unloading valve until the tank is emptied.

 

[Mitchelld]

am i right in saying then , that when i switch it on the pressure building should up should blow the unloader valve shut ? so that would mean th enloader valve seams to be jammed in the open postition ??? so therefor its faulty ?

or

there shoudlnt be any air in the unloading pipe to leak out the valve if the non return valve was working properly ? so the non return valve is faulty ?

bear with me really do appreciate the help

 

[Mitchelld]

im thinking replace the check valve forst and then the unloader if that doesnt work?