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Compressor Issues
The Doc - 14/2/10 at 06:10 PM

I have an old Compair Compressor. When it gets to about 100 PSI the motor starts to struggle, then eventually if left the fuse blows.

Knackered motor, capacitors. Any ideas which is the more likely?

TA

Mike

BenB - 14/2/10 at 06:12 PM

I know this is a silly question but does it have enough oil in it? Getting hot and seizing when under pressure?????

blakep82 - 14/2/10 at 06:12 PM

what pressure's it supposed to go to?
i thought 100psi was quite high, but can't remember what mine goes to.

if its supposed to go above 100psi, motor perhaps. if its supposed to stop at like 90 or something, pressure switch?

The Doc - 14/2/10 at 06:19 PM

I will check the oil level.

The original pressure switch, which is adjustable starts at 120psi then upwards. Actually I replaced this with a new one which is 120-150 range. I understand this is right for a large-ish compressor. This one has 125 litre tank

jacko - 14/2/10 at 06:20 PM

Has it just started doing this ?

RAYLEE29 - 14/2/10 at 07:31 PM

hi, not sure if its relavent but my compressor sounded horrible the other day it was extra cold outside now its warmed up a little it sounds fine
first things to do would be check the oil and drain the water from the tank
also make sure your gauge is reading correctly
Ray

martin1973 - 14/2/10 at 07:32 PM

one way valve between tank and pump.
mine does it
have you drained the tank lately?

The Doc - 14/2/10 at 11:35 PM

Thanks guys

Jacko - for a while but has got worse

Raylee - how could water cause this sort of prob? (I'll drain it off again anyway)

Martin - have you inspected the one way valve, replaced it etc. Where is it usually located in the system and what should I be checking for?

RAYLEE29 - 15/2/10 at 11:12 AM

just the first things to do with any compressor thats playing up
also if you had a lot of water in there the compressable air would be less volume
some people never drain and its surprising how much water can build up
Ray

wilkingj - 15/2/10 at 01:57 PM

quote:
Originally posted by RAYLEE29
also if you had a lot of water in there the compressable air would be less volume
some people never drain and its surprising how much water can build up
Ray



Also the water causes the inside of the tank to rust. Then after time it gets weak from the INSIDE, then it blows out.
Worst case is it busts the tank open showering the workshop with bits of shrapnel.

You should drain your air tanks of water on a regular basis.

Garages and the like have to have them tested for safety and insurance purposes.
They usually do this ultrasonically to detect thin patches (read this as rusting through from the inside).

Many of us are using old and second hand compressors. These are probably more likely to be rusted inside the tank.

So think safety and take care. Drain your tanks regularly.

rusty nuts - 15/2/10 at 08:49 PM

Garage compressors used to be tested by filling them with water under high pressure , don't know if things have changed.

David Jenkins - 15/2/10 at 10:06 PM

Same as model steam locomotive boilers - mine was tested every 2 years by filling it to the brim and pumping in more water until it gets to 1.5 x working pressure.

The advantage of pressurising a tank with water is that the water is near-enough incompressible and therefore stores no energy - if there is a leak the only thing that happens is a spray of water. On the other hand air can be compressed and any leak will result in catastrophic failure as the air's stored energy is released. And don't ask about steam when it's at 90psi!