Accumulator position

[gilesfordcrush]

Hello all. Can I fit an accumulator anywhere on the cold water system?

It would suit my plans if it was relocated to under the sink in the heads,
rather than in the lazarette next to the water pump.

Rapid advice much appreciated! I'm in the lazarette!

Giles

 

[pvb]

Yes, it can go anywhere.

 

[PaulRainbow]

It has to be fitted between the pump and the taps. It should be as close to the pump as possible, doubt a short distance will make a noticeable difference.

 

[Shearmyste]

If you think of the role of the accumulator it has two purposes one to be a pressure retention device so the pump doesn't have to run all the time the tap is opened and also to act as a pressure surge arrestor (when ours stopped working the hot water system used to blow pipes due to heating and expansion of the water), so as long it is after the pressure pump and before the hot water system calorifier then it will work. I assume by the question that the accumulator is not a vetus type as the pump is part of the accumulator which would need to be as close to the supply tank as reasonable to reduce suction losses.

 

[gilesfordcrush]

Ah, so at the other end of the boat isn't the best idea then?

Thanks for the replies chaps.

 

[pvb]

Ah, so at the other end of the boat isn't the best idea then?

Depends where the pump and the taps are! It can go anywhere in the cold water pipe, and will then allow smoother pump operation. The comment about calorifiers is a bit of a red herring - calorifiers should ideally be fitted with a non-return valve on the cold inlet and have their own separate accumulator.

 

[VicS]

The layout should be as close as possible to this:

 

[pyrojames]

It is useful to have a cold mixer on the out from the calorifier to control the output temperature too.

 

[gilesfordcrush]

My pump is at the stern, in the lazarette. I'm moving the pump to another spot in that area, but if I could fit the accumulator under the basin in the heads it would be ideal from a space and storage point of view. I have two taps in the cold system, and two in the hot (heads and galley). The pipe run from the pump to the heads is about 20ft, with a t-piece running to the galley about half way along this. In other words, if I put the accumulator in the heads it would be about as far way as possible from the pump!

I have a non-return valve on the cold water in to the calorifier. I expect it would be best to keep the accumulator in the lazarette, I just need to find a place to fit it ( and make a bracket) that is functional and takes up space as efficiently as possible.

 

[pyrojames]

My pump ISS the heads, but the accumulators (hot and cold) are in the galley.has been fine for the last ten years.

 

[pvb]

My pump is at the stern, in the lazarette. I'm moving the pump to another spot in that area, but if I could fit the accumulator under the basin in the heads it would be ideal from a space and storage point of view. I have two taps in the cold system, and two in the hot (heads and galley). The pipe run from the pump to the heads is about 20ft, with a t-piece running to the galley about half way along this. In other words, if I put the accumulator in the heads it would be about as far way as possible from the pump!

I have a non-return valve on the cold water in to the calorifier. I expect it would be best to keep the accumulator in the lazarette, I just need to find a place to fit it ( and make a bracket) that is functional and takes up space as efficiently as possible.

You could certainly fit the accumulator in the heads; it will still work. Pressure in the cold pipe is even throughout its length, so the positioning of the accumulator isn't in any way critical.

 

[RupertW]

In a larger boat with a couple of heads so lots of pipework I'm not sure an accumulator is needed. I say that because ours burst at the end of 2016 so I bypassed it and got the yard to fit a new one over winter. Testing things is not their strong suit as I learnt after a few expensive jobs were done but didn't work. In the case of the new accumulator they had left it bypassed.

We had some overnight open sea passages to do to get to our new marina so I left it bypassed for that trip. And the pressure pump worked away until it had reached the right pressure, stopped as normal and didn't come on every time the taps were used. So I'm guessing all the pipework to galley, calorifier, two heads and a cockpit shower provided enough elasticity to act like a small accumulator. So a year on, the accumulator is still sitting there unused and although it's easy to put it back into the circuit the time I would spend testing it and checking for leaks means it may never come up high enough up the priority list.

 

[PCUK]

Why not fit it and see how it goes?

Boat with the hot water blowing pipes off definitely needs a pressure relief valve on the calorifier. Highly dangerous without!

Accumulator tank burst? Presumably plastic rather than steel or extremely high switch off pressure?

 

[RupertW]

Why not fit it and see how it goes?

Boat with the hot water blowing pipes off definitely needs a pressure relief valve on the calorifier. Highly dangerous without!

Accumulator tank burst? Presumably plastic rather than steel or extremely high switch off pressure?

Steel and rusted through at the bottom where I couldn't see it - the membrane must have burst through the ultra thin rusty bottom then torn on the sharp edges created. When (if) I get the new one plumbed in again, then a lift and annual inspection will be added to my regular task list. However the bilge is no longer perpetually wet now as I've finally replaced the float switch on the bilge pump, so hope the new one won't rust through even in 17 years.