Compressor repairs

[encino_]

I inherited a compressor from my chippie, it's a Fiac 8 bar model.
I used it a few times, but now it's dead. Weird, was working one day, and the next just didn't. It won't operate at all, the tank just remains empty and useless.

So, I'm guessing it's either a repair job, or a throw away thingy. I say throw away, because if the repair is too much, I'd rather just buy a cheapie, since I'm only going to be using for a nail gun.

Can anyone recommend someone in Melbourne (pref Western Suburbs) that will do a good and reasonable priced repair? What do they normally charge for a service, or inspection etc?

Or alternatively, any suggestions what may be wrong with it,
and is it worth a crack myself?

Cheers

[Barry_White]

encino

First of all is it an electric one or a petrol one. If it is an electric one you may need to to check for broken wires in the lead or check the if the push/pull switch on top of the pressure switch hasn't been accidentally pushed in or switched off.

[Rossluck]

Compressor's are fairly simple things, encino_. They consist of a tank, a motor and a pump. I'm betting that yours is electric, so this is the process I would go through to check it out:

But firstly: if you are not familiar with electrical stuff, don't touch it.

Turn it on and listen carefully to see if the motor is "trying" to start. If there is no indication of it "wanting to go" (if it seems completely dead), I would check the plug, lead, and then the pressure switch to see if a connection has come loose.

If power is reaching the motor but it still won't start, I'd be suspecting either a burnt out capacitor on the motor, or a seized pump. If the pump had plenty of oil, chances are that it is OK, so this is surely an electrical problem. In fact, when I read your post, a burnt out capacitor was my first choice. If you're in the building trade, take it with you one day and ask a sparky to have a quick look at it for you. They've got plenty of time. :wink:

[encino_]

Cheers for the replies. Yeah it's electric.
To be honest I don't know if there was much oil in it or not, I don't really know much about them, so didn't know about maintenance. But I had only used it a couple of times, and I know the bloke who gave it to me was religious in his maintenance, so assume it was prob fine.
My dad is very electrically and mechanically handy, and whilst he too doesn't know about compressors, I could do worse than have him check out the things you mentioned. Cheers!

[Ashore]

Silly I know but have you tried to run it on a diffrent circuit, just a thought :rolleyes:

[rileyp]

If its a half decent compressor there will be a red button on the motor which you can press.
It is a thermal overload and prevents the motor from burning out when there is an overcurrent situation eg seized compressor.

[encino_]

Well, we pulled off the switch cover, looked around in there, cleaned it up a bit, and lo and behold it works again. Maybe something was loose we didn't see. Will see how it goes for a bit, but thanks everyone for the encouragement to have a crack...usually I'll just tinker regardless, but didn't want to potentially muck up an expensive compressor since I don't know anything about them.
Cheers

[encino_]

Hmm, well that was short lived.
What it does now is just fill up the tank to about 4 bar (half of it's normal psi), then just keeps on running. Like it wants to fill it up further, but can't. It won't turn it self off, like it normally does when it's full. Of course my nails are only going in halfway because there isn't enough pressure.
I topped up the oil before I used it.. my only thought is that maybe there's an air leak somewhere.. maybe when we moved it we knocked a hose or something. Not sure. But it seems to stay at the same level, like it reaches that same 4 bar level then just won't go any further. Doesn't really make sense for a leak...and it doesn't seem to be running out by itself either. I'll look in the morning to see if it's emptied overnight.

[Barry_White]

encino_

It maybe you need a new pressure switch.

[Ashore]

Wouldn't think so Barry if its only getting to 4 bar it could be the unloader on the compressor the the delivery valve or the relief , though you would hear it if it was :rolleyes:

[Wood Butcher]

If it is only getting to 4 bar but the motor is not stopping, my guess would be that it is the non-return valve in the compressor head. It may be allowing air back into the cylinders on the return stroke?

[Rossluck]

That's an odd one, encino_. I suspect, given the fact that it was dead before you cleaned up the electrics, that there's a problem with that electric motor. It may have overheated because it wasn't functioning properly and overheated the circuits in your switch. When you fiddled with it you somehow restored it's function. This is guessing.

A leaking valve in the pump doesn't answer the initial question of dead electrics. My guess is that the motor isn't functioning properly and can only pump up to 4 bar before there's an equalibrium of energy.

Have a sparky look at it. It's a process of elimination and one that I enjoy immensely.

[echnidna]

sounds like a loose or fractured wire

[Wood Butcher]

A leaking valve in the pump doesn't answer the initial question of dead electrics. My guess is that the motor isn't functioning properly and can only pump up to 4 bar before there's an equalibrium of energy. If it was an equilibrium of energy then the motor would stop or stall, not keep going. Quite possibly that there are a few things wrong and that is the reason the compressor was inherited!?

[rileyp]

but didn't want to potentially muck up an expensive compressor since I don't know anything about them.
Cheers
Take it to someone and get it looked at if not fixed.
There is a list as long as my arm of things it could and could not be.
If it is a expensive compressor treat it with the respect it deserves.
The fact its not capable of obtaining full pressure suggests either motor problems which will end up costing lots if continually abused.(bad run capacitor or faulty centrifical switch which will then burn out motor.
or as someone else suggested pressure switch or non return valve etc etc etc...

[Rossluck]

If it was an equilibrium of energy then the motor would stop or stall, not keep going. Quite possibly that there are a few things wrong and that is the reason the compressor was inherited!?


I'm no expert (is it Rowan?). What I was sort of getting to was that the motor might be running in start-up mode (this is dredging up what little I know about electric motors), that the contact points that kick the motor into full power aren't functioning properly. To my way of thinking the motor has very little power in start-up mode and might slow down at 4 bar in energy equilibrium. But it's just a wild guess.

The switch should be OK. I'd love to have the machine in my shed. :)

[rileyp]

I'm no expert (is it Rowan?). What I was sort of getting to was that the motor might be running in start-up mode (this is dredging up what little I know about electric motors), that the contact points that kick the motor into full power aren't functioning properly. To my way of thinking the motor has very little power in start-up mode and might slow down at 4 bar in energy equilibrium. But it's just a wild guess.

The switch should be OK. I'd love to have the machine in my shed. :)
wrong...
The motor has a high starting torque as is required by all compressor motors and the motor uses a high value capacitor to do this which allows a high current to run in the auxillary/start winding during start up.
When approx 75 full load speed is acheived the centrif switch is meant to operate and a lower value capacitor is used to maintain the rotating magnetic field.Failure of the centrifigal switch will cause the high value capacitor to remain in circuit and thus the start/auxillary winding will burn out as it can only carry the larger starting current for a short period of time.
I therefore suggest as previosly stated have it looked at.

Single phase motors with centrifigal switches are not to be tinkered with by people who know nothing of them unless they wish to burn them out!

A 240 volt 2hp compressor motor will set you back $300 approx + fitting

[Rossluck]

Yep. I was only guessing. I stand corrected.:D

[NCArcher]

Larger compressors have a small valve attached to the pressure switch which opens when the motor cuts out. This valve unloads the cylinder head (of compressed air) so the motor can start with minimal load on the cyl. head.
If this valve is stuck open or faulty it will prevent the compressor from getting to the set pressure.
Because you had a problem with the switch initially I would be having your electrician check this first.

[woodwork wally]

Hmm, well that was short lived.
What it does now is just fill up the tank to about 4 bar (half of it's normal psi), then just keeps on running. Like it wants to fill it up further, but can't. It won't turn it self off, like it normally does when it's full. Of course my nails are only going in halfway because there isn't enough pressure.
I topped up the oil before I used it.. my only thought is that maybe there's an air leak somewhere.. maybe when we moved it we knocked a hose or something. Not sure. But it seems to stay at the same level, like it reaches that same 4 bar level then just won't go any further. Doesn't really make sense for a leak...and it doesn't seem to be running out by itself either. I'll look in the morning to see if it's emptied overnight.
Hi is that Williamstown vic or nsw If victoria :)I may be able to help . Will be away for a day or 2 But email me a phone no On the e.m sender sight [dont send your number over the forum ] and I will be in touch when I get back:2tsup: Regards Wally