The Old Machinery Magazine Forum

Forum Categories => Driven Machinery => Topic started by: catmanjan on 09 November, 2020, 01:56:24 pm

Title: Ajax 1.5 piston pump strange behavior
Post by: catmanjan on 09 November, 2020, 01:56:24 pm
Hello I have a piston pump that I've been using to pump river water for some time now

I refurbished it before use, with new rubber and leather and seals.

Up until now it was running okay, but for some reason it stopped discharging water, I took the valve cap off the top and had a look and it wasn't drawing water though

Strange thing is, after I removed one of the valves it started working fine, albeit at half the speed

Does anyone know what could be going on? I would like to get the pump running at full speed, but every time I put the second valve back it stops pumping
Title: Re: Ajax 1.5 piston pump strange behavior
Post by: cobbadog on 09 November, 2020, 04:12:47 pm
Welcome to the forum catmanjan.
I am unable to help but there are many who can and will so just sit tight and the info you need will come along soon enough.
In the mean time is there any blockages in your pick up pipe, foot valve or where it enters the pump housing? Any foreign material inside the pump anywhere?
Title: Re: Ajax 1.5 piston pump strange behavior
Post by: catmanjan on 09 November, 2020, 05:05:24 pm
Thanks cobba - I've drained the foot valve and checked for blockages and all seems okay on that side

With one of the valves removed its pumping all the way up a 35 metre hill and filling a water tank (at half the usual speed)

I'm hoping someone who knows about these old piston pumps will be able to tell me straight away what the issue is, it seems like it would be an easy thing to diagnose, its just that they predate the internet by a bit too much for the info to be available on Google!
Title: Re: Ajax 1.5 piston pump strange behavior
Post by: cobbadog on 09 November, 2020, 09:26:31 pm
There are an awful lot of that pump around and a few guys here that can offer info. Can't help thinking that if it works with one valve out but not both is the 2nd valve in back to front?
Also can the one valve that is working now be swapped over with the 2nd one to see if it works?
I'm just tossing ideas out there. Only pumps I have played with is a centrifical and a reciprocating pump although one day I would like a double acting pump like yours.
Title: Re: Ajax 1.5 piston pump strange behavior
Post by: famous fitter on 09 November, 2020, 09:41:33 pm
Hi CMJ,

Sounds like it?s sucking air somewhere and when you removed the valve it primed it a bit?

I would check the suction and gland? ( I?m not 100% sure how it?s made) For air leaks.

Can you watch for air on the outlet? point the pipe straight up while it?s pumping - you may see bubbles ?

If the outlet valve is leaking it will suck/leak back a bit then push out less  volume.

Cheers Justin
Title: Re: Ajax 1.5 piston pump strange behavior
Post by: catmanjan on 16 November, 2020, 10:42:47 am
Hi CMJ,

Sounds like it?s sucking air somewhere and when you removed the valve it primed it a bit?

I would check the suction and gland? ( I?m not 100% sure how it?s made) For air leaks.

Can you watch for air on the outlet? point the pipe straight up while it?s pumping - you may see bubbles ?

If the outlet valve is leaking it will suck/leak back a bit then push out less  volume.

Cheers Justin

Thanks Justin, you were completely righ about the gland - I repacked it and now its working great
Title: Re: Ajax 1.5 piston pump strange behavior
Post by: famous fitter on 16 November, 2020, 07:29:41 pm
Hi CMJ

Glad it?s working properly again

Cheers Justin