Thread: Air compressor question

Originally Posted by blackhole

So there is a bunch of us who disregard the instructions/warnings and just switch it off at the wall. Is there any one who has a horror story of dieing compressors or flaming motors or a curse being put onto their workshop from not using the switch on the compressor?

If you use the switch on the powerpoint to start up your compressor (not saying you should) and your compressor is close by you can hear the motor starting up.If it doesn't start and you can hear the motor humming, switch it off straight away.That way it is unlikely you will damage the motor.But if the compressor is in a remote location and you can't see or hear it, then you could damage the motor if it doesn't start up the way it should.If you're lucky you might just have a blown capacitor. But you could also end up with a burnt out motor.


When I bought my compressor I got the "don't use a power lead" warning but how do tradespeople use their compressors on job sites???????

How do they burn out electric motors on job sites ??? By using long extension leads!!!.
If you have to use a long lead make sure it is at least a 15 or 20 Amp lead.And even then you have to be careful.The critical point is on start up.If it starts up ok then it's usually not a problem.

Instead of using a long extension lead,why not use a longer hose? If the job is far away from the compressor use a larger size hose (12mm) and you will not get much of a pressure drop at the point of use.





I understand the theory behind both these warnings but general practice points towards negligible risk.

I had a compressor repair business for 34 years and I can assure you that I've seen lots of burnt out compressors during this time.

Cheers
Walter

Originally Posted by walro

I had a compressor repair business for 34 years and I can assure you that I've seen lots of burnt out compressors during this time.

Cheers
Walter

So it was instruction disregarding people like me that kept your business running.

Apart from the cheap and nasty chinese imports, most compressors are built to a good standard and give you many years of reliable service.
Some people totally neglect the compressor and only look at it if there is no air coming out from the blow gun or there is a burning smell hanging around.Then they go and check the compressor (if they can find it) and find out that it ran out of oil.Next step is a visit to the local compressor repair guy.---"I only bought this heap of sh****t 6 months ago...it just stopped working."--- After checking the record,the machine was purchased 3 years ago.
But not everybody is like that. Some people take very good care of their machines. Do a regular Oil change, clean or replace air intake filters drain air receiver regularly, check vee belts,adjust belt tension,Pop safety valve under pressure to make sure it's working.Keep the machine clean and check oil level on a regular basis! Most compressors have very little oil in the sump and it doesn't take a big oil leak to run out of oil quickly.If that happens the compressor pump is usually stuffed.The big end will seize up on the crankshaft and to fix it will cost you more than a new compressor pump.

Originally Posted by walro

The part you're refering to is called a ball valve.

Thanks, always nice to learn the correct name.

One of the advantages of shopping at Bunnings is that you can leasurely search their isles and find what you need but you don't always learn the correct name.


Peter.

Hey, Walro?

You sound like the bloke to ask... as I mentioned earlier my comp is over 20yo now and has been a near daily user. I'm becoming a tad concerned, not about the compressor itself but about the reservoir.

It has seen a lot of water pass through it over the years and I'm wondering if there's any way to check the innards for bad rust spots short of physical pressure testing?

I guess what I'm asking is, is there any sort of "pre-test" one can do in the shed, which'd give an indication of whether taking it in to a pro for a pressure test would be a very good idea?

Sorta like the ol' "tap, while listening for dead areas" my Grandad used to espouse for boilers? Although I can't say I'd like to bet my safety on that particular method.

G'day Skew Ch.
They don't build compressors like they used to years ago.In the past all pressure vessels had to comply to Australian Standards specifications.Drawings to manufacture air receivers had to be submitted to the DLI (Workcover to day) for approval and only then could you build air receivers.Each tank would then get a crown stamp and a serial no stamped on the compliance plate.Only then was it legal to sell the product to the end user.Just about all tanks were built in Australia as the imported tanks were inferior and didn't meet Australian Standards.Then it must have got too hard for workcover.More and more cheap imports were sold in Australia with illegal tanks.When our company questioned workcover we were advised that as long as the compressors were in the dealers showroom they could'nt (or would'nt) do anything.They could only take it further once the compressor was sold and out of the dealers factory.What sort of a law is this?? Where does that leave to customer? In other words the Australian Standard specifications went out the window.(This is only the case with small compressors, with air receivers less than i think about 50 or 100 litres capacity)
For this reason our company refused to sell cheap imported compressors and only supplied Australian built machines with good back up of service and spare parts.

If your compressor is as you say about 20 years old then it is one of the good old machines.If it's still working ok and not using much oil, hang on to it.Chances are it will last you another 20 years if you look after it.
Don't worry about the tank to much.The steel plates they used to roll the tanks were much thicker than what you get to day.The cheap compressors are mainly fitted on tin cans.
If your tank should rust through what usually happens is, you get a pinhole first and air starts to leak from there.The compressor is not going to blow up in your face.But if it gets to this stage then that is the end of it. Toss it out! Never try to weld it or fix it some other way. That would then be dangerous.

What you could do for your own peace, of mind call a licenced boiler inspector to check your tank.He'll come to your place and check it on site.With ultra sound he can measure the thickness of the metal at the bottom of the tank.He will also check your safety valve, pressure gauge etc. and give you a certificate to say that the compressor is safe to use.
Hope this helps

Cheers
Walter

Guilty of turning off at the wall

Never had a problem - so far.

Have worked out my drainage problem - see the link.

http://www.woodworkforums.ubeaut.com...ad.php?t=75659

Will try to remember, in future, to turn it off the recommended way.

Regards,
Bob

Bob38S

Originally Posted by Bob38S

Guilty of turning off at the wall

Never had a problem - so far.

The reason why you haven't had any problems Bob is because you've got a good quality compressor made in Australia.The Betts electric motor fitted to your machine was also made in Australia and was built for air compressor duty with a high start up torque.
Also your McMillan compressor got a different unloading system fitted.It's called a Load Genie. It's a combination non return /unloader valve.It unloads the compressor head as soon as the compressor stops pumping.So, regardless of how you stop or start your compressor it should always start up ok.

Have worked out my drainage problem - see the link.

Well done Bob.I like the set up you made for draining the tank.Also the extra wheels you fitted makes it much easyer to move the compressor around in the shed.

http://www.woodworkforums.ubeaut.com...ad.php?t=75659

Will try to remember, in future, to turn it off the recommended way.

Regards,
Bob

Originally Posted by Bob38S

Have worked out my drainage problem - see the link.

http://www.woodworkforums.ubeaut.com...ad.php?t=75659

Missed that at the time Bob as I was recovering from my prostate operation.

Peter.

Thanks Walro - indeed an oldie but a goodie. Pleased to hear that I haven't been doing what could cause a problem later on. I knew of the Betts motor but not the other bits you mentioned - thanks for the info.

Peter, the drainage works really well - use any of the ideas if they suit your purpose.

Regards,
Bob

Originally Posted by walro

What you could do for your own peace, of mind call a licenced boiler inspector to check your tank.He'll come to your place and check it on site.With ultra sound he can measure the thickness of the metal at the bottom of the tank.He will also check your safety valve, pressure gauge etc. and give you a certificate to say that the compressor is safe to use.
Hope this helps

Thanks, Walter.

Peace of mind: priceless!

I leave my compressor on all the time and have no worries. I just turn off the control valve at the compressor so it does not leak through the fittings (most of them leak) and the compressor doesn't wake the neighbors at night.

I also make a point of releasing the pressure from the regulator at the end of each day.

regards
Anthony

Originally Posted by Big Shed

I only turn mine off when we go away, otherwise it is switched on all the time. Only comes on when I use some air.

what he said