Domestic Water

[Trev The Rev]

I'm having problems finding suppliers of domestic water accumulators for use on my narrowboat.

It currently has an accumulator of around 3 litres total size (spherical). Quite old now and well corroded and not fit for purpose.

I am also fitting a new sureflo pump etc. etc. and would like to replace the accumulator with a new one with much the same capacity.

Anyone out there know of a good on-line supplier of such a product, and what price to expect, the cheaper the better (as long as it is good quality).

Also - what are the various advantages and disadvantages between the older style accumulators that are pressurisable with Bladders and the newer plactic bottle jobs (that do not hold a pressure charge over the water).

[NB Alnwick]

I'm having problems finding suppliers of domestic water accumulators for use on my narrowboat.

It currently has an accumulator of around 3 litres total size (spherical). Quite old now and well corroded and not fit for purpose.

I am also fitting a new sureflo pump etc. etc. and would like to replace the accumulator with a new one with much the same capacity.

Anyone out there know of a good on-line supplier of such a product, and what price to expect, the cheaper the better (as long as it is good quality).

Also - what are the various advantages and disadvantages between the older style accumulators that are pressurisable with Bladders and the newer plactic bottle jobs (that do not hold a pressure charge over the water).

 

The one I have was supplied by Midland Chandlers

[NB Phoenix]

You could try this company they have a very good mail order system. Cleghorn Waring

[Gary Peacock]

Have a look HERE and search for accumulator. (Cleghorn Waring)

 

If you find one don't order it register HERE forum members get 10% discount, then message me with the items details and I will get some one to get in touch with you about how to order it.

Edited February 22, 2007 by Gary Peacock

[NB Phoenix]

SNAP!

[Keeping Up]

Trev,

 

You ask about the different types. I've always had the simpler type that is just like a plastic bottle with a pipe fixing at the bottom and a removable tap at the top. When you switch on the pump, it half-fills with water and compresses the air in the top; when you open a tap, the air expands and pushes about one half of that water out again until the pump starts. It works just fine like that, with no need for any other pressurisation. The disadvantage is that the air in the top gradually dissolves in the water, so about twice a year I have to switch off the pump, open a bath tap to let the water out (it's the lowest in the system), and undo the tap in the top of the accumulator to let some more air in.

 

Allan

[Trev The Rev]

Thanks for your input.

 

I now have a choice of accumulators to look at, what size would people recommended for four/six births (normally four adults using)

 

A connected question I have is:-

 

At present the pump (sureflo) has an integral pressure cut off switch around 30psi - I also have a seperate pressure cut off switch - Is the second stand alone pressure switch necessary, recommended or not needed.

 

It may be that a previous owner has replaced an older pump (without an integral pressure switch) with the newer version and just left the old stand alone pressure switch in place (the old stand alone switch looks as if it would be quite happy sitting in a museum ).

 

An comments or recommendations would be appreciated

 

Trev

[Moley]

Hi Trev,

 

Are you likely to be at the boat Fridaaay afternoon or over the weekend? If so I'll try to get down too and you can see how I've fitted mine. Accumulator bought from Limekiln for twenty-something.

 

The accumulator is only really to maintain a pressure in the system so that if you've got a dripping tap your water pump doesn't keep kicking in for a short burst every few minutes (can be quite annoying, especially at night), so size doesn't really matter.

[Trev The Rev]

Thanks Moley

 

Not sure when down on boat - Trying to squeeze in the odd hour here and there for maintenance - Thanks for the offer though

 

I'm familiar with use and function for accumulators - The one I have taken out is around three litres and does a good job.

New smaller ones tend to be either two or five litres (some even less), just wondering which one to go for as very little difference in price.

There is, of course, a small space penalty.

 

Forced to look at system this year when a handful of small leaks took my floor out before they were noticed. That's what comes from aquiring a boat that was stood around for some time. Think you've found the problem onto to discover floor not drying out. Have repaired two toilet leaks, pump leak, 3 joint leaks so far. Major strip down now in progress in the effective area.

 

Trev

[chris w]

Hi Trev,

 

The accumulator is only really to maintain a pressure in the system so that if you've got a dripping tap your water pump doesn't keep kicking in for a short burst every few minutes

It's also to prevent the pump cycling when you're running any tap slowly eg: brushing one's teeth for example. The pump pressure temporarily overcomes the loss of pressure due to the slowly running water and switches OFF. Immediately the pressure drops, due to the running water, and a second later the pump immediately switches back ON again and so on ad infinitum. This is not good for pump life and the noise is really annoying ON,OFF,ON,OFF etc.

 

The larger the accumulator the greater the water that can be drained, say at night if you have to visit the bathroom and wash your hands, without the pump's having to switch on. Typically 1 or 2 litres capacity is normal. With a diaphragm type, only half the given volume is water the rest is air above the diaphragm.

 

Chris

[magnetman]

Having no accumulator on my cold pump does reduce its service life compared with the hot pump which does have one. The on-off-on bit doesn't bother me much and I've got switches on both pumps to turn them off in the event of a dripping faucet. Worth ftting one, these pumps are quite expensive.

[Keeping Up]

At present the pump (sureflo) has an integral pressure cut off switch around 30psi - I also have a seperate pressure cut off switch - Is the second stand alone pressure switch necessary, recommended or not needed.

There are three possible reasons for the external switch:

 

1. A pressure which is lower than that set by the integral switch, may be necessary to protect the calorifier

 

2. The external switches are often adjustable, separately for the cut-in and cut-out pressure, so you can tailor them to your system

 

3. The external switches have the reputation of being more reliable than the integral ones (fact or fiction? I don't know)

 

Allan

[Split Pin]

I'm having problems finding suppliers of domestic water accumulators for use on my narrowboat.

It currently has an accumulator of around 3 litres total size (spherical). Quite old now and well corroded and not fit for purpose.

I am also fitting a new sureflo pump etc. etc. and would like to replace the accumulator with a new one with much the same capacity.

Anyone out there know of a good on-line supplier of such a product, and what price to expect, the cheaper the better (as long as it is good quality).

Also - what are the various advantages and disadvantages between the older style accumulators that are pressurisable with Bladders and the newer plactic bottle jobs (that do not hold a pressure charge over the water).

 

 

Got mine from ASAP supplies,ordered online you get a discount good range of sizes available

 

Steve

[Theo]

Trev,

 

You ask about the different types. I've always had the simpler type that is just like a plastic bottle with a pipe fixing at the bottom and a removable tap at the top. When you switch on the pump, it half-fills with water and compresses the air in the top; when you open a tap, the air expands and pushes about one half of that water out again until the pump starts. It works just fine like that, with no need for any other pressurisation. The disadvantage is that the air in the top gradually dissolves in the water, so about twice a year I have to switch off the pump, open a bath tap to let the water out (it's the lowest in the system), and undo the tap in the top of the accumulator to let some more air in.

 

Allan

 

 

Allan's accumulator has to be mounted the correct way up. The other type uses a diaphragm to separate the water from the air. This can be mounted any way up. The air on the other side of the diaphragm is pressurised using a car pump when you first install it.

 

Theodora doesn't have an accumulator and AFAICT doesn't need one. You don't get the rapid short cycling that has been described and the lack of accumulator means that you are warned of a dripping tap rather more rapidly!

 

Nick

 

Edit: PS I wonder if the horizontally mounted calorifier has an ari space at the top. If it has it will be behaving like an accumulator.

 

While I am still thinking, I have a theory that it matters not in the least where the accumulator is installed. Am I right?

Edited February 22, 2007 by Theo
Add more thoughts

[old what]

I'm having problems finding suppliers of domestic water accumulators for use on my narrowboat.

It currently has an accumulator of around 3 litres total size (spherical). Quite old now and well corroded and not fit for purpose.

I am also fitting a new sureflo pump etc. etc. and would like to replace the accumulator with a new one with much the same capacity.

Anyone out there know of a good on-line supplier of such a product, and what price to expect, the cheaper the better (as long as it is good quality).

Also - what are the various advantages and disadvantages between the older style accumulators that are pressurisable with Bladders and the newer plactic bottle jobs (that do not hold a pressure charge over the water).

 

 

Have you tried plumbworld http://www.plumbworld.co.uk/584-0000 I got an expansion vessel from them for the central heating. Their online shop was very efficient and reasonably priced.

[chris w]

While I am still thinking, I have a theory that it matters not in the least where the accumulator is installed. Am I right?

 

It must be between the pump and the first junction to the taps to be effective.

 

Chris

[skeets]

It must be between the pump and the first junction to the taps to be effective.

 

Chris

 

We have an accumulator fitted on winging-it which work fine, it fills about a kettle with water before the pump kicks in, but we get pulsing on the pump as the system recharges. The accumulator has an adjustable valve for regulating pressure inside the accumulator, any idea on what pressure it should be set at or do we just have to live with the pulsing?

[old what]

We have an accumulator fitted on winging-it which work fine, it fills about a kettle with water before the pump kicks in, but we get pulsing on the pump as the system recharges. The accumulator has an adjustable valve for regulating pressure inside the accumulator, any idea on what pressure it should be set at or do we just have to live with the pulsing?

 

Think of the accumulator as a storage vessel one side has water capacity and the other side as air with the diaphragm separating the two the bigger the vessel the more water you should be able to draw before the pump charges the vessel again. The air side of the vessel is pressurised the higher the pressure the more pressure on the water leaves the vessel I think!

[chris w]

The air side of the vessel is pressurised the higher the pressure the more pressure on the water leaves the vessel I think!

 

Not right actually. The air pressure needs to be set at just below the pump switch-ON pressure. This pressure must be set with the pump disconnected electrically (so it doesn't switch ON while you're setting the pressure) and with a tap open.

 

If the air pressure is set above the pump switch-ON pressure you won't get the whole volume of accumulator water available. Suppose, for example, the accumulator were set at 25psi and the pump didn't switch ON till 20psi and switched OFF at 30psi (fairly typical pump figures). Then at switch OFF the water in the accumulator is at 30psi. As you open a tap the accumulator will push water out until the pressures equalised at 25psi. After that the water would start to trickle to a drip as a vaccuum would be created.

 

If the accumulator is set at say 17psi, then water will be forced out until the water pressure reached 17psi, BUT at 20psi the pump will cut in first and the flow is kept going.

 

Chris

[skeets]

Not right actually. The air pressure needs to be set at just below the pump switch-ON pressure. This pressure must be set with the pump disconnected electrically (so it doesn't switch ON while you're setting the pressure) and with a tap open.

 

If the air pressure is set above the pump switch-ON pressure you won't get the whole volume of accumulator water available. Suppose, for example, the accumulator were set at 25psi and the pump didn't switch ON till 20psi and switched OFF at 30psi (fairly typical pump figures). Then at switch OFF the water in the accumulator is at 30psi. As you open a tap the accumulator will push water out until the pressures equalised at 25psi. After that the water would start to trickle to a drip as a vaccuum would be created.

 

If the accumulator is set at say 17psi, then water will be forced out until the water pressure reached 17psi, BUT at 20psi the pump will cut in first and the flow is kept going.

 

Chris

thanks mine seems to be working fine as far as flow is concerned but we were trying to find out if we can stop pump pulsing after taps are turned off and the system is pressurising

[chris w]

thanks mine seems to be working fine as far as flow is concerned but we were trying to find out if we can stop pump pulsing after taps are turned off and the system is pressurising

 

The accumulator WILL stop the pulsing. If you are still getting pulsing then it may be the accumulator air chamber is leaking or the diaphragm has a hole in it internally. You do have a diaphragm type accumulator I assume?

 

Chris

[skeets]

The accumulator WILL stop the pulsing. If you are still getting pulsing then it may be the accumulator air chamber is leaking or the diaphragm has a hole in it internally. You do have a diaphragm type accumulator I assume?

 

Chris

yes it has a diaphram .

[Trev The Rev]

Thanks to everyone for all your replies - very helpful.

 

It would appear the best size accumulator to use would be the largest possible for the small enclosed space I already have under a sink unit that houses the pump - That will be around 5 litres. The old one was 3 litres so not much difference in size really.

 

Some of the sites I have now visited say maximum accumulator effect is when installed as close to the pump as possible, but can be installed anywhere on the pressurized side. Some also give a guide on setting the pressure above the membrane (one simply to set it to half operating pressure with pump off and system open at taps ie. no water pressure) another by connecting up a small water jet to the output (shower head etc.) so flow is horizontally and then adjust air pressure to give the steadiest stream of water possible, as indicated by the water stream. This seems a nice practical way to set it up (I like practical, real life solutions).

 

Still not totally convinced about the reason for a secondary pressure swith - yes it would give greater flexability and adjustment in some settings (my new pump already has an adjuster on the pressure switch). It would also provide a backup switch in case one failed (but would I know the main switch had failed until the second one also fails?)

 

As to maximum pressures - a water pump is normally set to 30psi (2 bar) - minimum allowable household pressure at an house stop cock is 1 Bar with many authorities having their own minimum of 1.5 to 2 bar at the stop cock, some properties would be greater ( 2 bar only gives enough pressure to lift the water 20 meters (not very good if you live on the 10th floor). The max allowable pressure for the pump before failure is 60psi or 4 bar - the switch cannot be set this high. (Info Source). In view of this I am not so sure the calorifier would have any problems with the pressure ranges available from the pump. The tank must also be fitted with (and is) a pressure relief valve. Colorifiers I have found have a max working pressure of 3 bar (5-6bar tested) and pressure relief valves are normally preset to 3bar (plumb centre).

 

Knowing myself better than most - I will probably install the second pressure switch - possibly even a secondary pressure regulator after the accumulator - it depends very much upon cost and if I think it worth the effort.

 

Thanks for your help

 

Trev

[chris w]

Thanks to everyone for all your replies - very helpful.

The tank must also be fitted with (and is) a pressure relief valve. Colorifiers I have found have a max working pressure of 3 bar (5-6bar tested) and pressure relief valves are normally preset to 3bar (plumb centre).Trev

 

 

Trev

 

Ideally you also want to fit a second accumulator after the calorifier in the hot water line between the calorifier and the first tap. This second accumulator will act as an expansion vessel. Without it, your pressure relief valve (PRV) will continually dribble away with hot water.

 

This is because water expands by about 4% and having no where to go it opens the PRV. An expansion vessel will solve this issue. In terms of size, the figures for a typical 60 litre calorifier are as follows:

 

Expansion of water @ 4% = 2.4 litres

 

The expansion vessel (accumulator) will have a diaphragm so half its volume is available for water with the rest being air above a diaphragm as before; the quoted size is for the whole volume. Therefore a 5 litre expansion vessel should suffice.

 

If you have a larger calorifier then scale the expansion tank appropriately. This time the pressure above the diaphragm should be set so that it is above the pump cut-off point (typically around 30psi) but below the PRV setting of typically 42psi (3bar). So a setting around the high 30's should be OK.

 

Chris

Edited February 24, 2007 by chris w

[smileypete]

We have an accumulator fitted on winging-it which work fine, it fills about a kettle with water before the pump kicks in, but we get pulsing on the pump as the system recharges. The accumulator has an adjustable valve for regulating pressure inside the accumulator, any idea on what pressure it should be set at or do we just have to live with the pulsing?

Hi,

 

It may be there's a restriction between pump and accumulator, eg a kinked or undersized hose or pipe. If the pump's pressure switch is set quite low, and/or the pump is a high flow one it will exacerbate the problem.

 

This sort of problem isn't easy to diagnose via a forum, probably best to wait until you can find someone to look at it.

 

cheers,

Pete.