Accumulators are a small tank which is fitted on a narrowboat as close to the pump outlet as you can. The pressurised water supply at the cutoff pressure partially fills the tank, which is itself charged with pressurised air.
Your fresh water and pressurised air in the tank are separated by a rubber membrane.
This allows pressure energy generated by the pump to be stored and released by the compression and expansion of the air behind the rubber membrane.
This dampens out fluctuations in supply pressure, which permits the pump to be switched off for short periods with no loss of water supply.
Benefits of an accumulator
Less cycling of the pump.
Prolonging pump life.
The ability to flush a loo or fill a glass of water in the night without the pump running.
Some accumulators are supplied for narrowboats pre-pressurised. The amount is normally shown in the manufacturer release notes.
Always check this charged pressure as is maybe much too high to even allow water flow so the accumulator has to be matched with your Pump.
Normally the accumulator is fitted with a Schrader valve like on your car tyre. With a tyre pressure gauge or bicycle pump you set the correct pressure. A helper maybe handy to turn the pump on and off at the fuse panel.
Firstly locate the air valve on the accumulator, this may be under a screw cap. You need to know the cut-in pressure of your pump.
Here is the procedure for setting it up.
1. Turn the pump off at the fuse panel and then open a tap until the water stops flowing.
2. Now measure the air pressure in the accumulator with the tyre pressure gauge.
3. Check the pressure in the accumulator .
4. Change pressure to your CUT IN PRESSURE on the pump. (let out air) or (put air in)
5. Close the tap and turn the pump back on at the fuse board and test the flow.
Your pump should now run smoothly with no spitting or cycling.
The cost of an accumulator runs around the £70.00 mark.
Here is a nice video on accumulators
Accumulators as expansion tanks
In addition to being an accumulator, they can also be used as an expansion tank for your calorifier, thus taking the pressure off the walls of your calorifier tank.
All you do is depressurise the tank completely, this will then allow water to enter the tank relieving the pressure.
If you do this it helps to stop your calorifier tank splitting from excess pressure.
Please click the picture for a pdf larger onscreen presentation about accumulators.
