Accumulator in fresh water system

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Joker

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I have an accumulator in the fresh water system. I don't know the make, and it's difficult to access. I suspect it's lost its pressure [when you turn the tap on, you get a very slow dribble for several seconds before the pump kicks in].
I know it's a 'how long is a piece of string' question, but what should the pressure inside the accumulator be?
 
There are two types of accumulator. One has a bladder, which you pressurize. The clue is an inflator valve. The other type of accumulator is merely a chamber full of air, closed at the top, but connected to the water at the bottom, so that the air is compressed by the water pressure. Sometimes, with the latter type, the air disappears, and it has to be drained. Which type is yours?
 
I'd suspect the pressure switches in the pump rather than the accumulator. If pressure leaks from the system then the pump should come on and try to bring the pressure back to the switch off point.

You say that water dribbles out when tap opened, so no pressure (or there's a blockage). Then pump kicks in and flow starts (if it's normal then initial slow flow isn't down to a blockage).
 
You say that water dribbles out when tap opened, so no pressure (or there's a blockage). Then pump kicks in and flow starts (if it's normal then initial slow flow isn't down to a blockage).
Click to expand...
Given the way they've been tucked away under the sink, access to the pump would be easier than access to the accumulator.

There's virtually no pressure at all when I first open the tap - a small flow dies away to a dribble before the pump kicks in. That does sound like the pump sensor.

I had thought of replacing the pump with a Jabsco Parmax 3. Anyone any experience of this?
 
Joker said:
Given the way they've been tucked away under the sink, access to the pump would be easier than access to the accumulator.

There's virtually no pressure at all when I first open the tap - a small flow dies away to a dribble before the pump kicks in. That does sound like the pump sensor.

I had thought of replacing the pump with a Jabsco Parmax 3. Anyone any experience of this?
Click to expand...

Or is the tap not opening properly at first......... ???? What you observe is difficult to explain in terms of accumulator pressure or even pressure switch operation .

If the pressure sensor was sticky but the accumulator working correctly you'd expect a good flow initially, but to fall away as the pressure in the accumulator falls.
At worst mal-operation of the accumulator would result in rapid on/off cycling of the pump when the tap is partly open.

A new pump is an expensive way of fixing what might be a fairly trivial fault but if chucking money at a problem is your way of doing things fair enough.
 
Joker said:
Given the way they've been tucked away under the sink, access to the pump would be easier than access to the accumulator.

There's virtually no pressure at all when I first open the tap - a small flow dies away to a dribble before the pump kicks in. That does sound like the pump sensor.

I had thought of replacing the pump with a Jabsco Parmax 3. Anyone any experience of this?
Click to expand...

Or is the tap not opening properly at first......... ???? What you observe is difficult to explain in terms of accumulator pressure or even pressure switch operation .

If the pressure sensor was sticky but the accumulator working correctly you'd expect a good flow initially, but to fall away as the pressure in the accumulator falls.
At worst mal-operation of the accumulator would result in rapid on/off cycling of the pump when the tap is partly open.

A new pump is an expensive way of fixing what might be a fairly trivial fault but if chucking money at a problem is your way of doing things fair enough.
 
VicS said:
Or is the tap not opening properly at first......... ???? What you observe is difficult to explain in terms of accumulator pressure or even pressure switch operation .

If the pressure sensor was sticky but the accumulator working correctly you'd expect a good flow initially, but to fall away as the pressure in the accumulator falls.
At worst mal-operation of the accumulator would result in rapid on/off cycling of the pump when the tap is partly open.

+1, just a thought could the pipework between the pump and the outlet have collapsed? This may allow a trickle initally until the pump cuts in and the flow from the pump would "re-inflate" the hose... But, any way it does sound like some sort of restriction in the pipework, than either a pressure switch or accumulator tank fault.... (have you checked the voltage at the pump when the pump is running, voltage drop can cause really wierd faults at times?)

Jon
Click to expand...
Click to expand...
 
I have a Seagull IV filtered supply on its own tap in addition to a normal water tap. The filter has been in place for two seasons, which seems to have resulted in partial blockage. It behaves in a manner rather similar to your description, whereas the normal tap functions correctly. Jabsco Par Max 3.5 plus accumulator. I suspect you have a blockage of some sort.
 
After reading this, I tired a couple of tests - open tap and let it run until pump kicks in. If I do this repeatedly, there is a good flow at first which dies away. With the heads tap it was 27 seconds from opening hot tap to pump starting; with galley hot tap it was about 20 seconds. With the cold tap, the delay was only about 10 seconds.
The hot water tank is quite some distance from the pump and hot water tap [maybe 4-5m of pipe there and and the same back].
Once the pump starts, everything is okay.
 
Joker said:
After reading this, I tired a couple of tests - open tap and let it run until pump kicks in. If I do this repeatedly, there is a good flow at first which dies away. With the heads tap it was 27 seconds from opening hot tap to pump starting; with galley hot tap it was about 20 seconds. With the cold tap, the delay was only about 10 seconds.
The hot water tank is quite some distance from the pump and hot water tap [maybe 4-5m of pipe there and and the same back].
Once the pump starts, everything is okay.
Click to expand...


A good flow at first taking around 20 secs to fall away suggest that the pressure accumulator is doing what it should do.


The pump is failing to cut in because ....... ?????:

Thinking aloud, if that's allowed:-

The pressure switch is sticking open..

Or a NRV on the pump discharge is sticking shut keeping the pressure switch pressurised ..... I don't think you've said what pump it is so dont know if this is a valid suggestion or not.
Possible ??? that someone in the past has added a NRV to the pump discharge, which is now sticking ??
 
The pump is original - eight years old. The problem's gradually been getting worse over the last few years. There've been no modifications to the system.
The pump is a Shurflo diaphragm pump.
 
If you follow the simple procedure I outlined in post 9 of this thread http://www.ybw.com/forums/showthread.php?408954-Water-Pressure it will tell you all you need to know, actual cut in pressure (which will definitively confirm if it is too low), cut out pressure and will set the accumulator exactly where it should be. All you need is a cheap bike pump with pressure gauge, no guesswork.
 
David2452 said:
If you follow the simple procedure I outlined in post 9 of this thread http://www.ybw.com/forums/showthread.php?408954-Water-Pressure it will tell you all you need to know, actual cut in pressure (which will definitively confirm if it is too low), cut out pressure and will set the accumulator exactly where it should be. All you need is a cheap bike pump with pressure gauge, no guesswork.
Click to expand...

We don't know yet whether his accumulator is the type that requires to be charged up. See post #3.
 
He'll soon find out when he tries it and can't find the Schrader valve, progress in itself, though from the time lag before the pump kicks in I my money is on a bladder type.
 
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