Compressors

[Boo]

I need help with my compressor. FIAC Miami 50 liter tank. When I switch it on, it pumps up, then, when it is full, it does not cut out. I have to stop it on the control switch. Then, when I drain off some air and switch it on again it cannot turn over the motor. It tries to go but needs a push of the flywheel to get it moving again. Anyone know about these things?

[JayDub]

There's usually an adjustment for the tank pressure, is this set too high? Also this could be faulty, I think it's struggling as the tank is full. Careful it doesn't blow - that could be fatal, for you too.

[Sin_Tiger]

I think you have one or more electrical / control issues.

The pressure switch should stop the compressor and open the drain to unload the discharge line pressure. When the compressor starts, it should run for a few seconds with the drain open to clear any condensation and allow the motor to get up to full speed before closing.

I'm also concerned that the discharge line check valve might be leaking, that might explain the difficulty turning from stopped. It's possible that the capacitor on the motor is stuffed but it's less likely (I'm assuming it's a single phase motor) I'd have a look at the pressure switch / drain valve first.

[Boo]

The pressure valve is I think, the brass job under the switch. This is not leaking, but,it does not seem to move when I poke the small rod inside. This is what I was suspecting but would like to know for sure before I get a new one. This would possibly explain the not stopping bit, but would it be the reason for not starting? I can blow through the pipe on the valve so that is clear.

[Bixxer Bob]

Mine did this, I replaced the whole lot with an aftermarket kit from fleabay.

[Boo]

I think you have one or more electrical / control issues.

The pressure switch should stop the compressor and open the drain to unload the discharge line pressure. When the compressor starts, it should run for a few seconds with the drain open to clear any condensation and allow the motor to get up to full speed before closing.

I'm also concerned that the discharge line check valve might be leaking, that might explain the difficulty turning from stopped. It's possible that the capacitor on the motor is stuffed but it's less likely (I'm assuming it's a single phase motor) I'd have a look at the pressure switch / drain valve first.

I think you are right here!I replaced the cut out switch, the small brass job under the electrical on/off switch, no show. It does not blow off when the tank is full. I assume the blow off valve is the little jobbie on the main air feed from the cylinders to the tank. this does not seem to do much, but, when I push the button in, it does release some air. But, it still does not want to turn over when it starts again. Any suggestions?

[Sin_Tiger]

The "blow off" valve on the tank is a Safety valve, every pressure vessel has to have one by law. The little button is a test button just to prove the moving parts are free. Don't FFF with that 

Switch the power supply off and disconnect it. Try to turn the compressor by hand, keep your fingers (and or gloves and loose clothing, ties, dentures etc. ) out of anywhere they could get trapped, specifically the compressor wheel or where the belt runs onto the groove. Disconnect the pipe between the compressor and the tank nearest the compressor, SLOWLY! If air starts to leak out STOP, there is a good chance that the check valve is leaking and the drain / unloader (if fittted) hasn't worked. If you get air, drain down the tank, there will be a small valve on the base of the tank, if you don't know where it is  Tut Tut as you should be draining the water out regularly. Drain the tank until you get no more air out. Try turning the compressor again or starting it on the electric power if your feeling brave. If it's easy to turn or starts up straight away then the problem is with the discharge line check valve / unloader / drain valve. If you can's identify those or that item then you need some onsite help.

How old is the machine?

[Boo]

I think I may have sorted the overload problem. I fitted a new pressure blow off valve. The one under the electrical on/off switch. Now when I reach full pressure it will stop. However, it does need to be adjusted for a bit less pressure. I will look at this tomorrow. Now all I have to do is to get the thing to start. After it reaches full pressure and  then blows off, the flywheel now moves without any resistance to compression, but when the pressure drops, the electricity switches on, but the motor is reluctant to turn over. If I give the flywheel a shove then off it goes happy as Larry until full pressure is reached and blaa blaa blaa.  And yes, I do drain the tank after every use. It would be nice to sort as I don't want to loose my fingers in the flywheel.
The machine is about six years old, but has had very little use.

[Sin_Tiger]

Right, my next check would be to see if the motor starts on its own as I now suspect the motor capacitor but if the unit you have is as per the specs and the photo below, that's going to involve removing either theycompressor or the motor rather than just taking a belt off with this being a direct coupled 220V single phase unit.