Air compressor problem

[Deo]

Hi guys I am new here and hope I get some useful help.

I got an air compressor (Fini 200 ltr) 3hp motor belt driven with this pump (http://www.ebay.co.uk/itm/Clarke-Co...t=UK_Hand_Tools_Equipment&hash=item2582f31b41) common for many air compressors.

The problem is that compressor is taking ages to fill up. The gauge seems to be stuck but eventually it fills up after an amount of time. The electric motor seems to heat up and many cases it operates the thermal switch.

Checked the check valve (no return valve) there is no air leak. it just leak few air on start-up when compressor tank is empty but stop after few seconds. I tried to turn wheel on compressor even when tank is full and it turns normally there is little hising sound of compression or suction.

Last week I was using an air saw this model ( http://www.ebay.co.uk/itm/Air-Body-...Air_Tools_and_Compressors&hash=item48596b0c22) and compressor could not stop working to fill up until the thermal switch got in.

I am suspecting that air compression is low or maybe stuck check valve restricting air in tank. What do you think?

Sorry for the long essay but tried to be specific as possible.

 

[rtbcomp]

Welcome to the forum.

Have you any means of measuring the speed of the motor, with the belt removed?

 

[MoreWellie]

check the pump cylinder head bolts, they worked loose on my compressor and the symptom was that it took forever to get up to pressure

I couldn't find any torque settings but mine turned easily when I tried them. Please don't over tighten them though, I used a short wrench held by finger tips

 

[rtbcomp]

According to my SIP compressor manual

M6 Screw 9 to 11 Nm
M8 22 to 27 Nm
M10 45 to 55 Nm
M12 76 to 93 Nm
M14 121 to 148 Nm

 

[Deo]

Will check them for sure.

A little dietail the compressor tank is also getting hot and I am continuously draining water from the tank.

 

[rtbcomp]

It could be a weather thing. If the tank is getting hot you're definately compressing air. You say you're located on Earth, is this the centre of the Earth by any chance?

What pressure is the tank reaching?

Is the pressure gauge you're using accurate?

 

[Deo]

Yes weather is hot here. The compressor cut out at 10 bar 140 psi but the thermal switch is cutting out at around 130psi from an empty tank.

How can I check motor rpms ?

 

[rtbcomp]

You'll need an optical rev counter, but I wouldn't worry about that now we know a bit more, I would say the compressor is operating outside its comfort zone.

Set the cutout to 100 psi, my Clarke struggled to reach 150 from new.

For comparison, my 10 year old Clarke 3hp takes about 4 mins to raise pressure in a 217 litre tank(s) from 0 to 80 psi.

 

[Bill Edwards]

Do you know how big the tank is?
And how long is it taking - what is a long time?

 

[Deo]

From an empty tank it will not fill as at 130 psi the thermal switch is triggered. As said when I was using the air saw the compressor again could not stop until thermal trigger. Anyways I had a chance checking bolts and all was tight so I opened the head and found out a lot of junk (debris) on top of both pistons and valve assembly. I dissembled the pump complete. Oil was contaminated with debris, including debris in the crank bearing. This is a second hand compressor bought from an auto body shop two yeas ago.

Conrods bearing have a lot of marks, crank seems ok.

 

[Rig Pig]

Sounds like it's had a hard life!

 

[mfletch]

Is the air filter clean if not this can reduce its performance dramatically

 

[Deo]

I think it was used without filter at some point or something. Pistons and bore are not bad.