Time to build pressure

[PandaWill]

Hi all

Just serviced my new (to me) compressor. I've changed oils / cleaned filters and adjusted the belt.

It's a 5.5HP 200ltr tank and takes

2.5 mins to reach 50psi
8 mins to reach 100psi
11 mins to reach shut off which reads about 125 psi

Does that sound OK?

Will

 

[tigler]

No, thats an excessive time. A 3hp, twin cylinder, 250 ltr, belt drive unit I sold recently would go from zero to 125 psi in around 4 mins. It was about 8 years old, well used but in good working order.

 

[rtbcomp]

My Clarke 3hp 150 litre + 3 x 13Kg gas bottles (78 litres) and a 17 litre tank takes 6 mins to get to 100 psi. So thats 245 litres

Didn't test it when it was new.

Doesn't mean there's anything wrong with Will's compressor though, it may be slower running to reach a higher pressure or just keep wear & tear down. My good old Clarke starts to struggle above 115 psi.

 

[PandaWill]

Interesting - thanks for the replies.

I must admit my gut feeling was that it is slow to get to pressure. It seems to struggle once past 50 psi.

The background is that it's a 2007 machine that's been heavily used in the back of a tyre fitting van.

Judging by the colour of the oils that have come out of both engine and compressor it's also had very little maintenance.

With that in mind what could I do to improve performance?

Thanks
Will

 

[rtbcomp]

Ah, it's not electric then, could be the engine's down on power. Have you tried servicing the engine?

 

[brightspark]

next question is how many cfm is the pump . just because it has a large tank and a 5hp petrol motor doesnt stand to reason that the pump is large . it would only be used for blowing tires up

 

[rtbcomp]

They'd use it for the tyre machine and pneumatic jacks too, but they could rely on an oversize tank to supply a lot of air to be used intermittently.

Even so it shouldn't struggle at 50psi.

 

[PandaWill]

Pump is an Abac B3800B which from what I can tell is 16.8cfm.

On playing with the compressor just now I notice that if I kill the engine at 50psi quite a lot of pressure is let out of a small (I guess breather) hole in the top of the oil fill tube. If I then open the head drain handle it lets out a lot of air until it gets down to about 25psi - then stops.

You can probably tell I am new to the world of compressors - any help gratefully received.

Thanks again

 

[Tiggy_dorset]

Pump is an Abac B3800B which from what I can tell is 16.8cfm.

On playing with the compressor just now I notice that if I kill the engine at 50psi quite a lot of pressure is let out of a small (I guess breather) hole in the top of the oil fill tube. If I then open the head drain handle it lets out a lot of air until it gets down to about 25psi - then stops.

You can probably tell I am new to the world of compressors - any help gratefully received.

Thanks again

Sounds like air is escaping past the pistons and rings into the crankcase.

 

[rtbcomp]

Also if it's feeding back from the tank the non-return valve may be iffy too.

 

[PandaWill]

Hi fellas

The Abac technician has told me that the model of compressor I have should take 7 minutes to reach full pressure. Now I've changed oils and done a service it reaches full pressure in 9 mins 50 secs.

So I am quite happy with that - I won't be using it that often so maybe I will do a gasket change in due course but no rush.

Also I've installed a filter regulator so I am now OK to use my nice new air ratchet

Thanks for your help

Will