Fitting an accumulator

two

two

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My water pump pulsates when only cold water is being drawn and I don’t like the idea of so much current being switched on-and-off repeatedly. I’m assuming that an accumulator placed on the cold line will overcome that. Has anyone done so with good effect?
 
Sorry to disappoint.
I am wondering about the chance of success, though!
 
If it's pulsating because the cold tap is only partially open an accumulator won't help.

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At full pelt, there's too much water flowing. I thought that the frequency of "pulses" would reduce in proportion to the capacity of the accumulator?
 
Not done it but can tell you that any accumulator will need to have its damper pressure set at a level suitable for the pump pressure feeding the liquid side.
Have you looked at one in particular that is suitable for your pump?
 
Figaro said:
could you not just restrict the flow by some means ? a simple g clamp on the flexible tube might do it, adjust until desired flow achieved
Click to expand...
That's no different to partially opening the tap.
The pipe pressure is too high as the water flow is too low causing the pump to surge.
The only solution is a different pump with a lower pressure and flow rate.
 
I agree about flowrate being the problem. I think the installed pump has been chosen to be 'beefy' enough to provide a good shower, even if water is being diverted to the kitchen sink.
In my case the pump does not switch on-and-off when drawing hot water and I assume that the boiler provides some capacity but, as there is a NRV, it cannot do the same for cold water.
If an accumulator is no good on the cold side, I wonder what the purpose of an accumulator is?

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The accumulator has a fixed pressure so doesn't work over all flow rates.
Fiamma has an air chamber pressure of around 13psi so any less water pressure than that won't effectively compress the air in the chamber.
More than 13psi will compress it so it depends on your pump pressure.
Actually, looking at it that way it probably would work as the pump back pressure is higher at reduced flow, lower at max flow.
 
Had a fiamma pump and accumulator on a CI van no problem with pulsing, next van same pump no accumulator and had pulsing, accumulator fitted no pulsing.
Current van sureflo pump with pulsing, waiting on an accumulator to be fitted next two weeks who knows 3rd time lucky!?
No guarantee the accumulator fixed problem but in my mind fair odds
 
I'm not sure this helps but we have one fitted, you can see it to the right of the pump in the picture below. However, we didn't notice any significant pulsing before it was fitted.
The converters fitted it as part of a campaign to replace the original pumps they fitted, which had suffered failures. It's main advantage seems to be you can flush the loo at night without the pump starting. :)

P8080013.jpg
 
Yes they work well. The pressure in the accumulator can be adjusted via the Schraeder valve on the end. They cannot stop the pump pulsing but they can dramatically reduce the frequency so there's no hammering effect as several seconds elapse between one pulse and the next.
 
tonyidle said:
Yes they work well. The pressure in the accumulator can be adjusted via the Schraeder valve on the end. They cannot stop the pump pulsing but they can dramatically reduce the frequency so there's no hammering effect as several seconds elapse between one pulse and the next.
Click to expand...

I totally agree with Tonyidle on this. I fitted an accumulator on my narrowboat and it saved the pump pulsing and as said allowed the loo to be flushed without the pump starting. Easy to fit and if I remember correctly I set the pressure to about 15 psi (not 100% sure on that figure but it easy enough to experiment with various pressures).


Dave

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Happy1 said:
Had a fiamma pump and accumulator on a CI van no problem with pulsing, next van same pump no accumulator and had pulsing, accumulator fitted no pulsing.
Current van sureflo pump with pulsing, waiting on an accumulator to be fitted next two weeks who knows 3rd time lucky!?
No guarantee the accumulator fixed problem but in my mind fair odds
Click to expand...
I'll be interested to hear the outcome.
 
Accumulators seem to be fairly common in the boating world. I recall that the sensors switching the pump on and off could be adjusted for cut-in and cut-out pressures, which should be higher than that of the accumulator.
 
Accumulators are very widely used on boats, partly because they use pressure regulated pumps and partly to smooth the flow from positive displacement pumps. Fitting one to a van water system should give a smooth flow and you really can have them what ever size you want. On my last boat I had a 5 litre one on the hot side to cope with the expansion of water in the calorifier. I would think a .5 litre one would be fine in a van.
 
Either,
Sureflo too big so had a tiny whale unit fitted, result no more pulsing, third time lucky!!
 
Sorry rogher!!

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I think I'll be fitting one, too. I've found that it's much more pronounced when on EHU (battery at 13+V), so some sort of voltage stabilisation might be an alternative solution. No pulsing at around 12.5V.
 
http://www.johnscross.co.uk/products/fiamma-a20-expansion-tank.html

Fiamma A20 Expansion Tank
The universal expansion tank.

An ideal addition to the Aqua 8, Aqua F, previous models and all other types of pressure switch pumps (for example Shurflo and Flojet).

The expansion tank eliminates the pulsating operation of pressure switch pumps and supplies a constant flow of water in the required quantity. It extends the life of the pump and boiler and cuts water consumption.

The internal pressurized diaphragm provides a smooth, surge-free flow of water.

The A20 can be dismantled for diaphragm repair and checks.

It is precharged at 0.9 bars (13 psi) but it can be charged with the special valve with a normal compressor so it can be adapted to all pressure switch pumps
 

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