Water Pressure

wiggy

wiggy

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This is driving me nuts. The pump works fine and is only 2 years old, when it pumps pressure is fine, when accumulator tank takes over pressure is pathetic, if using hot the thermostatic mixer can't cope with the pressure change and the temperature at the tap fluctuates, not a problem unless your in the shower, freezing cold to too hot.
Do I increase the pressure in the accumulator so the pump runs almost constantly without pulsing or does anyone have another solution.
I know I've asked before but no solution has yet fixed the problem.
 
That's the kiddy, try it without the accumulator, does run all the time when a tap is open but pressure is good and consistent shower temp.
 
The pump should run constantly, the accumulator only smooths the flow and prevents too much cycling of the pump when drawing off small amounts, it does not provide pressure except on initial start up. When a tap is opened the pump should come on after a pause and go off after a pause when the tap is closed. Do you have the accumulator set to just below the pump cut in pressure (measured not the one advertised)
 
David2452 said:
The pump should run constantly, the accumulator only smooths the flow and prevents too much cycling of the pump when drawing off small amounts, it does not provide pressure except on initial start up. When a tap is opened the pump should come on after a pause and go off after a pause when the tap is closed.
Click to expand...
I'm glad you've said that.
When I first got my boat the pump only came on periodically when a tap was on but now comes on as you discribe.
That's saved me some head scratching :encouragement:
 
David2452 said:
The pump should run constantly, the accumulator only smooths the flow and prevents too much cycling of the pump when drawing off small amounts, it does not provide pressure except on initial start up. When a tap is opened the pump should come on after a pause and go off after a pause when the tap is closed. Do you have the accumulator set to just below the pump cut in pressure (measured not the one advertised)
Click to expand...
I have increased the pressure but don't know what the actual pressure of the system is. How can this be found, I don't have a guage for water pressure? should I just pump up the accumulator until the pump is constant and let a little out.
 
David2452 said:
The pump should run constantly, the accumulator only smooths the flow and prevents too much cycling of the pump when drawing off small amounts, it does not provide pressure except on initial start up. When a tap is opened the pump should come on after a pause and go off after a pause when the tap is closed. Do you have the accumulator set to just below the pump cut in pressure (measured not the one advertised)
Click to expand...

So is an accumulator necessary or is it just an added complication for no real benefit?
 
wiggy said:
I have increased the pressure but don't know what the actual pressure of the system is. How can this be found, I don't have a guage for water pressure? should I just pump up the accumulator until the pump is constant and let a little out.
Click to expand...

You don't need a water pressure gauge, just a bike pump or car pump with a decent gauge, here's how to do it.
Pump off, tap open, set accumulator pressure to about 5psi. Taps closed pump on. When pump stops, open tap slightly, As soon as pump cuts in, turn of pump and close tap, a helper is needed here. Now check the accumulator pressure which will be the cut-in pressure. Open a tap and set the accumulator pressure to a few psi below pump cut-in pressure. Close the tap and turn on the pump, all ready.
 
Vara said:
So is an accumulator necessary or is it just an added complication for no real benefit?
Click to expand...

In my view the major advantage of an accumulator is that it reduces the on / off of the switch action and arcing so increases life, it does also have the advantages of smoothing things out a bit and not coming on when you get a glass of water, I like them big so even filling the kettle doesn't operate the pump. All the foregoing is of course contingent on them being set up correctly.
 
Here's a setup method that doesn't require a gauge. Depress the central pin in the accumulator's Schrader valve to let all the air out (assuming it to be a bladder type accumulator) Open a tap, which will cause the pump to run constantly. Begin pumping air into the accumulator, upon which the pump will run more intermittently. As you pump more and more air in the pump will begin to run constantly again. Let air out until the pump rest periods are maximised. Close the tap.
 
vyv_cox said:
Here's a setup method that doesn't require a gauge. Depress the central pin in the accumulator's Schrader valve to let all the air out (assuming it to be a bladder type accumulator) Open a tap, which will cause the pump to run constantly. Begin pumping air into the accumulator, upon which the pump will run more intermittently. As you pump more and more air in the pump will begin to run constantly again. Let air out until the pump rest periods are maximised. Close the tap.
Click to expand...
Same here: on my boat, also with a Parmax 3, the pump does NOT run constantly, it maybe runs about 50% of the time when drawing water or running shower. As the accumulator tank is working, it does vary pressure at the tap/shower but only very slightly. Fisrt two/three seconds of using a tap the pump does not run at all. I think the OP's accummulator tank is either duff or not pressurised correctly.
 
PCUK said:
Although the pump may not need an accumulator if there is a hot water system the accumulator will also act as an expansion tank preventing the pressure relief valve blowing off on the calorifier.
Click to expand...

Depends where its fitted, if its upstream (the usual place when only one is fitted) of the non return valve supply to the calorifier it will have zero effect in absorbing hot water expansion, you need two to achieve that.
 
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