ABAC Compressor Issue

[aaronm1234]

Hi all,

First post here as ive seen a lot of helpful posts here and hoping someone can shed some light on my problem. I have an ABAC B3915 Compressor 200L wired to a 13amp plug. My issue is when using the compressor normally from an empty tank it will start no issue and take some time to fill up which is normal I believe. My problem is that if I was to use the compressor and come back the next day and try to start it with 50 or more PSI in the tank (tank not fully empty) It will try to start up turn the motor over a few times and then trip the fuse in the garage. I had a look online and found out that my pressure switch seems to be rated for 16 amp 240V single Phase link attached. https://www.compressorshop.co.uk/ne...-?search_string=s-9063084&records_per_page=10.

Would this be why the compressor is tripping the fuse when the tank is not empty because its possibly drawing more power on startup with air in the tank as opposed to being empty ? It can take about 5 minutes for the tank to drain fully most times when trying to use the compressor and its a small inconvenience but when your using the machine every day its very annoying having to drain it empty before each use and then let it fill up to max again before using.

When using the compressor normally for example drained tank, filled back up and start spraying with the compressor there is no issues at all when the tank goes to refill after reaching say 50-70 psi before running the motor again it does not trip the fuse only trips when there is air in the tank and I come back the next day to use the compressor.

Any help appreciated, thanks

 

[brightspark]

might be the one way valve between the tank and pump leaking and filling the pipe with air making it harder to start under load ,disconect the pipe of the valve and test for leakage back over from tank

 

[Dutch Welder]

Unloader valve stuck could very well be it.
Normally the unloaded valve empties the pipe from head to tank, so when the motor/pump starts it has no pressure to work against for a moment, that small amount of time gives the motor time to spin up.
If the unloaded valve is stuck then the pressure will remain in the piping so right from the moment the pump and motor try and start the air pressure is working against it, thus giving the motor no time to spin up.

 

[dave h 2]

On startup mine hisses a lot till over 20psi then it stops until switch off when it vents loudly. That's the unloader operating normally emptying the pipe from the pump to the tank. Yours isn't

 

[aaronm1234]

Thanks all , I should I’ve mentioned I’ve replaced a load of parts already on the compressor as it was second hand when I bought it. New NRV, safety valve, gaskets, oil, pressure switch and basically everything except the motor and the head itself. Dave I do notice the hissing at the start when the tank is empty until around 20psi also and then the hissing stops. I am not sure where exactly/if my compressor has an unloader valve or if it is also known as the Non/return valve(NRV) I have replaced that also with a brand new one.

 

[dave h 2]

Follow the start up hiss cos thats the unloader follow the plastic pipe from the NRV to the electrical switch. The switch end may need cleaning

 

[aaronm1234]

Follow the start up hiss cos thats the unloader follow the plastic pipe from the NRV to the electrical switch. The switch end may need cleaning

Thanks. Ill check that today and see if theres anything and if it needs cleaned out/changed.

 

[Dutch Welder]

Can you post a picture, then we can point out the Non return valve.

It usually is mounted directly at the reciever, has the pipe from the head going to it, and also a small hose to the on/off switch.
If you replaced it did you use liquid pipe seal or tape??
It could be that a small piece of tape has come loose and now allows the non return valve to bleed a bit, thus filling the pipe from the head to the tank.

 

[aaronm1234]

Can you post a picture, then we can point out the Non return valve.

It usually is mounted directly at the reciever, has the pipe from the head going to it, and also a small hose to the on/off switch.
If you replaced it did you use liquid pipe seal or tape??
It could be that a small piece of tape has come loose and now allows the non return valve to bleed a bit, thus filling the pipe from the head to the tank.

Here is a picture of the same compressor from Ebay should give a good idea of my own. Both exact same setup. I replaced it with tape to seal the threads.

 

[voipio]

A brand new non-return valve can leak back. All it takes is a bit of gunk from the compressor to find its way to the surface of the pastel (aka rubber sealing losenge) and you have a leaky valve.

 

[indykid]

Red circle is the non return valve, yellow dashed line is the unloader line, the unloader valve is in the pressure switch assembly circled green. There may also be a poppet valve in a fitting somewhere between the pump and the non return valve that hisses on startup.

If you find the NRV is leaking back, they can be disassembled and cleaned pretty easily - the cap on the left of the image screws off and reveals the seal and a light spring. It might take a good lean to get the cap off though.

If you press the red button on the pressure switch as it's filling, it should vent the unloader line with a hiss (and obviously stop the pump). It should do the same when the pump cuts out when it reaches pressure.

 

[aaronm1234]

Red circle is the non return valve, yellow dashed line is the unloader line, the unloader valve is in the pressure switch assembly circled green. There may also be a poppet valve in a fitting somewhere between the pump and the non return valve that hisses on startup.

If you find the NRV is leaking back, they can be disassembled and cleaned pretty easily - the cap on the left of the image screws off and reveals the seal and a light spring. It might take a good lean to get the cap off though.

If you press the red button on the pressure switch as it's filling, it should vent the unloader line with a hiss (and obviously stop the pump). It should do the same when the pump cuts out when it reaches pressure.

View attachment 489712

Thanks ! I will check the NRV/unloader valve today and check the spring and pastel also to see if there is any dirt/gunk or if anything doesn't look good. I do hear the hisses when the when the compressor is filling/filled as you said above so its a pretty strange problem but hoping I can get it resolved.

 

[indykid]

Also worth considering what capacity and type of breaker is supplying the circuit? I noticed you said the fuse in the garage blows, not the fuse in the plug top

 

[aaronm1234]

Also worth considering what capacity and type of breaker is supplying the circuit? I noticed you said the fuse in the garage blows, not the fuse in the plug top

That is where I think my problem is, the plug fuse is blowing when trying to start the compressor if any air in the tank I thought it was because it would be more of a power draw that way as opposed to being fully empty and starting up which has no issues. I noticed that the power switch should be 16amp 240V going by the part description I have listed in the first post. My compressor has been wired to a 3 Pin 13amp Plug and blows every single time I try to start the compressor up with air in the tank. If the tank is empty it starts no issue but any air in the tank say above 20psi its guaranteed to blow the fuse in the plug.

 

[voipio]

Also check the oil level in the sight glass. It should be roughly midway up the glass.

Then there's the motor start/run capacitor that's worth checking. A faulty cap can cause similar symptoms to those observed in the original post. .

 

[indykid]

That is where I think my problem is, the plug fuse is blowing when trying to start the compressor if any air in the tank I thought it was because it would be more of a power draw that way as opposed to being fully empty and starting up which has no issues. I noticed that the power switch should be 16amp 240V going by the part description I have listed in the first post. My compressor has been wired to a 3 Pin 13amp Plug and blows every single time I try to start the compressor up with air in the tank. If the tank is empty it starts no issue but any air in the tank say above 20psi its guaranteed to blow the fuse in the plug.

The 16A just means the contacts are sized to allow 16A current draw, it doesn't change the current the appliance it's attached to draws. You could use it on an appliance that only draws 1A and it would be fine, but it might overheat if used on an appliance that draws 25A.

It wasn't clear from your OP that it was the plug fuse blowing. If it was the MCB in the consumer unit, MCBs have different operating characteristics, type B is 'normal' but type C will allow a larger in rush current without tripping...but that won't affect the plug fuse.

It still sounds like an intermittent unloader issue, but your comments about it restarting when it's filled recently but not when stood don't quite stack up. The unloader should operate with the motor contacts so while ever the motor is off, the unloader line should be open to atmosphere. I'd try removing the unloader line next time it's been filled and left stood and see if there's any pressure in it before trying to start it.

 

[aaronm1234]

The 16A just means the contacts are sized to allow 16A current draw, it doesn't change the current the appliance it's attached to draws. You could use it on an appliance that only draws 1A and it would be fine, but it might overheat if used on an appliance that draws 25A.

It wasn't clear from your OP that it was the plug fuse blowing. If it was the MCB in the consumer unit, MCBs have different operating characteristics, type B is 'normal' but type C will allow a larger in rush current without tripping...but that won't affect the plug fuse.

It still sounds like an intermittent unloader issue, but your comments about it restarting when it's filled recently but not when stood don't quite stack up. The unloader should operate with the motor contacts so while ever the motor is off, the unloader line should be open to atmosphere. I'd try removing the unloader line next time it's been filled and left stood and see if there's any pressure in it before trying to start it.

Thanks, so when testing this should I expect to have pressure built up in that unloader line or no pressure ?

 

[indykid]

Thanks, so when testing this should I expect to have pressure built up in that unloader line or no pressure ?

If the motor is running, there should be pressure in the unloader line. If the motor is stopped, there should be no pressure.

It's just occurred to me, are you switching the compressor on and off from the button on the pressure switch or at the socket? If you switch it off at the wall while it's filling, the unloader valve won't cycle so could keep pressure in the pipework upstream of the NRV (realistically, I'd be astounded if it didn't leak down through the pump overnight though, but if the NRV is passing slightly, it could keep the pipework pressurised).

 

[dave h 2]

Nice one Indy,
Last line from the OP which I missed the bold bit below -
When using the compressor normally for example drained tank, filled back up and start spraying with the compressor there is no issues at all when the tank goes to refill after reaching say 50-70 psi before running the motor again it does not trip the fuse only trips when there is air in the tank and I come back the next day to use the compressor.

Aaron
Do not switch these things on and off at the wall socket use the button, if you previously had a little direct drive comp the unloader is mechanical and operates on it's own.

 

[aaronm1234]

If the motor is running, there should be pressure in the unloader line. If the motor is stopped, there should be no pressure.

It's just occurred to me, are you switching the compressor on and off from the button on the pressure switch or at the socket? If you switch it off at the wall while it's filling, the unloader valve won't cycle so could keep pressure in the pipework upstream of the NRV (realistically, I'd be astounded if it didn't leak down through the pump overnight though, but if the NRV is passing slightly, it could keep the pipework pressurised).

If I’m done using the compressor I’ll always turn it off at the pressure switch then pull the plug from socket never while it’s running/filling. Now that you mention it does leak slightly from somewhere (I assumed poorly sealed thread on my behalf) and if there’s air in the tank say half full and I come back next day it’s usually empty or 90% empty so there is a small leak somewhere