Dumb newbie needs help with a compressor

[funstuie]

the pressure of the tank controlled approx by the motor starting and stopping , is set by the +/- control,one gauge shows tank pressure,gauge nearest wires,othr gauge with valve circled is the line pressure,this is adjustable by the large knob on top,normally have to lift up or push down to change pressure ,don't force it as there are other types of locking used on some machines, you would normally turn line pressure down to paint spray ,,maybe 20-60 psi ,instead of tank pressure of 100psi+

Thanks for that it makes sense sort of.

I just need to work out what I should set the tank pressure at.

 

[gavuk]

What tools are u planning on using stuie? tank pressure normally 100-120 psi ,the brass relief valve will blow if u set +/- too high ,then regulate pressure to your tool using regulator /gauge with quick release coupling and ball valve........hope thats clearer gav

 

[shenion]

Yes 100-120 PSI is normal.

Most air tools are designed for 90PSI. So, you want the compressor to turn on near 100PSI and off at 120.

There should be a plate or stamp with the rated pressure on the tank. Most single-stage compressors will do about 125PSI, 2-stage will do 175.

Just because it may be able to do more, there is no sense setting the pressure higher than needed. Yes, it will give you more flow for a short period; however, the pump and motor will be working harder.

My tankis rated at 150PSI, the compressor probably can do 140 (it has when the limit switch went bad.) I set mine to shut off at 120. I would go a bit lower, but the pressure switch already turns on very near 90PSI.

as Gavuk saig, you use the regulator to set the pressure. Mine is set to 90PSI to run my air tools. My spray guns have a small regulator on the gun itself to set the pressure. This is better for airflow as there is higher pressure to force the air down a long hose.

 

[funstuie]

So the little brass nut on top of the switch set the tank pressure? There is only a +/- on either side, there is no indication of what pressure it's actually set at. Do I just turn it to + and then watch what it fills up to?

 

[funstuie]

The than is rated at 150psi and the switch at 175psi.

 

[shenion]

Yes, adjust until it suts off at the desired pressure. I find they tend to vary until they "settle in" so watch the pressure for a few fills.

 

[gavuk]

it can vary between compressors the +/- nut changes the pressure needed to switch on or off the motor ,idealy set the motor will start when your lower required prssure is still present in the tank and stop before pressure relief valve blows.ie 90psi lower and 110psi higher,although this may vary slightly .What tools will you be using??????...spray guns will require lower amounts of air than say d/a or impact wrench .You will find an impact wrench will make compressor start shortly after pressing the trigger and it may not stop until after u finish ,a spray gun will take much longer for motor to start and switch off quickly .Your compressor looks good............ belt drive units will keep up with your demand better than direct drive ,typically dirct drive produce 8-9 cubic feet of air/min....and smaller belt drive maybe 14+cubic feet/min so will cycle on/off much less frequently........hope this helps ...being very general as we don't know your intended use for the compressor,although it really only changes output pressure/line pressure when the electrical switch is set correctley ........Gav

 

[funstuie]

I would like to run a nibbler, spray gun, maybe the following Air Body Saw, Belt Sander, Air Die Grinder, Air Cut Off Tool.

I have got the tank pressure up to 100psi by turning the screw towards the + but the screw is almost out now so I don't think it's going to go higher.

I only have a spray guy at the moment so I can't really test properly. I can press the spray gun constanly for about 5/6 minutes and the motor kicks back in. There is air escaping from about the outlet pipe section. Should these be loose? There is a sort of ball joint but air is escaping from this pipe so i tightened it up so it's now no longer a moveable ball joint.

 

[gavuk]

did u notice the pressure the tank was at when the motor restarted?die grinder,cut off tool and spray gun should all be ok nibbler ,belt sander and body saw will be the test ,don't use those tools myself so can't really say ,if your compressor is made up could well be up to the most demanding of tools ,if you can borrow a tool to try first or buy one at a time ,my dual action sander was too much for my first compressor .......When u say ball joint do u mean the elbow in the red circle from earlier pic?then i wouldn't say it should be loose.....hope this helps ....gav

 

[funstuie]

I have finally got round to using this compressor in anger and it's not going to well.

The tank pressure builds up to 110psi according to the dial, using just a blow gun constantly for 4 minutes and the motor kicks in. I got a die grinder and after 1 minute of constant use the motor kicks in. This doesn't seem right for 50l compressor with a 3hp motor.

I think it needs a proper service from someone who knows what they are doing.

 

[rtbcomp]

I have finally got round to using this compressor in anger and it's not going to well.

The tank pressure builds up to 110psi according to the dial, using just a blow gun constantly for 4 minutes and the motor kicks in. I got a die grinder and after 1 minute of constant use the motor kicks in. This doesn't seem right for 50l compressor with a 3hp motor.

I think it needs a proper service from someone who knows what they are doing.

To be honest that sounds about right. If it was clapped out it wouldn't reach 110 psi.

In the period between the tank being upto 110 psi and the motor kicking in there's nothing that a service could fix unless it was leaking air badly. If it holds the pressure under zero demand there will be no leaks.

50 litres isn't a particularly big tank.

Once the motor kicks in what pressure does it settle at whilst you are using a tool?

 

[funstuie]

I'm not too sure I never checked. I usually just wait till the motor shuts out to start using the tool again. Can I still use the tool while the tank is refilling?

 

[rtbcomp]

I'm not too sure I never checked. I usually just wait till the motor shuts out to start using the tool again. Can I still use the tool while the tank is refilling?

Of course you can, you just have to watch the "duty cycle" this should be indicated in the instructions. It's the ratio of motor onff time over 10 minutes, for example 50% duty cycle means 5 mins on, 5 mins off. I would guess a 3hp unit would have a 100% duty cycle, I run my Clarke belt-driven 2hours at a time continuously whilst grit blasting.

 

[funstuie]

Oh right.

I don't have any instructions and I can't actually find any for this model.

 

[rtbcomp]

I've just had a look at your original picture - I'd say that was well capable of running continuously.

This is the nearest I can find in Machine Mart, This but looking at the picture of yours the pump looks out of proportion to the tank.

I'd give it a go, I don't think the pressure will drop all that much to be honest. If you have the regulator set higher than necessary the tank will drain more quickly.

 

[funstuie]

Thanks for that, I had downloaded those instructions already but the model is completely different so it was a bit confusing.

I usually set the regulator at what the tool instructions say. I didn't know I could continue using it when the motor kicks in.

 

[homer]

You can not set the tank pressure higher than the relief valve is rated on the tank. In fact set the tank pressure 15 to 20 pounds less the the relief valve is rated for.

 

[MrFluffy]

This is the nearest I can find in Machine Mart, This but looking at the picture of yours the pump looks out of proportion to the tank.
.

I was looking at the pic and had a dingdong moment, its the same pumping unit as I have on my little homebrew 3 phase compressor I think. I know the pumping unit and motor on that came from a garage forecourt automatic 50p in the slot jobbie.
Mine runs constantly when Im using a lot of air blasting or greedy air tools. It does run warm after a while, but my pulley has fan blades on the spokes which help...
I would guess the mm pump went bad, and your seller being a compressor engineer just retrofitted a industrial pump onto it
Ill try get a look at it later see if theres any model names.

 

[rtbcomp]

......I would guess the mm pump went bad, and your seller being a compressor engineer just retrofitted a industrial pump onto it
........

That was my impression, the pump looks quite big for the tank, although that could be the camera angle. If he's replaced the pump amd the motor that should be as good as anything you'll get for the money.

 

[funstuie]

I was looking at the pic and had a dingdong moment, its the same pumping unit as I have on my little homebrew 3 phase compressor I think. I know the pumping unit and motor on that came from a garage forecourt automatic 50p in the slot jobbie.
Mine runs constantly when Im using a lot of air blasting or greedy air tools. It does run warm after a while, but my pulley has fan blades on the spokes which help...
I would guess the mm pump went bad, and your seller being a compressor engineer just retrofitted a industrial pump onto it
Ill try get a look at it later see if theres any model names.

The pump is new, he replaced it as the switch was broke. He obviously could get the parts cheap and just put a new switch and 3hp pump on it.

It works well now. But it's a bit loud. I think it needs a good service and clean.