Fitting domestic water pressure accumulator

[pcatterall]

Trying to find an annoying 'pulse' from my water pump, it occurs about once a minute, I've been all over the boat looking for what must be a very small leak, not found it yet but will persevere!!
During my search through the maze of pipe work I find that the pressure accumulator is fitted between the pump and the gas water heater.
Is this normal or should it be maintaing pressure on the whole system?
Perhaps the water heater has to have water at a constant pressure.
Its a Jabsco 1 L accumulator, I cant find the manual on board.
Any ideas please?

 

[VicS]

Trying to find an annoying 'pulse' from my water pump, it occurs about once a minute, I've been all over the boat looking for what must be a very small leak, not found it yet but will persevere!!
During my search through the maze of pipe work I find that the pressure accumulator is fitted between the pump and the gas water heater.
Is this normal or should it be maintaing pressure on the whole system?
Perhaps the water heater has to have water at a constant pressure.
Its a Jabsco 1 L accumulator, I cant find the manual on board.
Any ideas please?

If no leaks can be found perhaps it's the valves in pump not seating properly and allowing the pressure to leak back through the pump.

 

[vyv_cox]

Disregarding some losses through the pipework, pressure acts equally throughout the system, so it doesn't really matter where the accumulator is. However, for best efficiency in overcoming the losses it is normal to site it close to the pump. The only gas water heater I have owned was on a boat that didn't have an accumulator and it worked perfectly. The flow from yours must be more constant than that.

 

[Hoolie]

Depends which Jabsco accumulator you have. I had one WITHOUT a diaphragm and after a while (9 months?) the air all disappeared due to solution in water. It then has to be disconnected and drained once or twice a year.

So yours, though connected, may be doing nothing as the pump activates at one minute intervals. This suggests that wherever your small leak is, the accumulator is not working properly.

 

[MrCramp]

I don't think that you have a leak at all, that is why you cannot find it.

I have just been looking for my Jabsco Accumulator manual but it must be on the boat. Yours is connected in the place Jabsco recommend. Inside it is just a void, full of air, and when the pump works a certain amount of water is forced into it. You have too much water in it, which happens over time.

The purpose of the accumulator is to stop the cycling that you are experiencing and it can only do so if there is a certain proportion of air/to water. You need to disconect the water supply from the bottom of the accumulator and then unscrew the bleed valve which is on the top of it. This will release the water out of the accumulator. Tighten the bleed valve, connect the water up and your problem should have ceased.

PS. Just found the manual online, and luckily it supports my previously written diagnosis!!!
http://www.xylemflowcontrol.com/files/12573_1_litre_acc_tank.pdf

 

[VicS]

I don't think that you have a leak at all, that is why you cannot find it.

I have just been looking for my Jabsco Accumulator manual but it must be on the boat. Yours is connected in the place Jabsco recommend. Inside it is just a void, full of air, and when the pump works a certain amount of water is forced into it. You have too much water in it, which happens over time.

The purpose of the accumulator is to stop the cycling that you are experiencing and it can only do so if there is a certain proportion of air/to water. You need to disconect the water supply from the bottom of the accumulator and then unscrew the bleed valve which is on the top of it. This will release the water out of the accumulator. Tighten the bleed valve, connect the water up and your problem should have ceased.

PS. Just found the manual online, and luckily it supports my previously written diagnosis!!!
http://www.xylemflowcontrol.com/files/12573_1_litre_acc_tank.pdf

The accumulator prevents cycling of the pump when water is drawn off slowly. It will become ineffective if the air cushion is absorbed ( or leaks)

The OP is complaining about the pump pulsing approx every minute.

This is not due to the loss of the air cushion, it occurs because the pressure is dropping to the point at which it cuts in.
It can only do this if there is a leak. If there is no external leak then the leak is back thorough the pump and its valves require attention.

However a very brief pulse at frequent intervals does also indicate that the accumulator probably has lost its air cushion. Once that is restored the frequency of the pulses should diminish but they will be of longer duration.

 

[vyv_cox]

The accumulator prevents cycling of the pump when water is drawn off slowly. It will become ineffective if the air cushion is absorbed ( or leaks)

The OP is complaining about the pump pulsing approx every minute.

This occurs because the pressure is dropping to the point at which it cuts in.
It can only do this if there is a leak. If there is no external leak then the leak is back thorough the pump and its valves require attention.

However a very brief pulse at frequent intervals does also indicate that the accumulator probably has lost its air cushion. Once that is restored the frequency of the pulses should diminish but they will be of longer duration.

I agree. My water system originally had no accumulator at all but the pump did not operate provided there was no leak (and the valves in the pump were OK). As soon as the tap was turned on the pump operated continuously until it was turned off. Adding an accumulator allowed the pump to operate less frequently, topping up the accumulator instead of supplying the tap.

 

[charles_reed]

I agree. My water system originally had no accumulator at all but the pump did not operate provided there was no leak (and the valves in the pump were OK). As soon as the tap was turned on the pump operated continuously until it was turned off. Adding an accumulator allowed the pump to operate less frequently, topping up the accumulator instead of supplying the tap.

Try re-pressurising the accumulator using an ordinary car pump through the Schrader valve on the top.
I keep mine at between 1.2 and 1.5 bar.
Low pressure in the accumulator results in highly variable pressure on the input side of the geyser causing it to cycle on and off. Inadequate pressure will also sometimes cause the pressure switch to be fooled and the pump to not re-start when the water has all run through.

 

[NormanS]

Try re-pressurising the accumulator using an ordinary car pump through the Schrader valve on the top.
I keep mine at between 1.2 and 1.5 bar.
Low pressure in the accumulator results in highly variable pressure on the input side of the geyser causing it to cycle on and off. Inadequate pressure will also sometimes cause the pressure switch to be fooled and the pump to not re-start when the water has all run through.

As has been pointed out already, there are two types of accumulator. One has a rbber "bag" in it, which, as you say, has to be pressurised, using the valve on top. The other type is merely a cylindrical vessel with the water connection at the base, and a plug at the top. The latter type does not require to be pressurised, but does occasionally need to be disconnected, and drained.

 

[Gwylan]

Sounds a bit familiar. Had a similar problem with occasional hunting.

Turned out that the accumulator was bust - nothing I did made an difference. This included replacing the pump with no result - chucked the original one in the skip. Doh!

Replaced the accumulator and never looked back.

Nice people at Jabsco are very helpful and good at taking your money so painlessly.