Fresh water pressure problem

[nlawley]

I have two water tanks. The water flows good with one water tank but slow from a second water tank. It was fine until yesterday. I have a Comet pressure equalizer installed which is almost totally full of water. There doesn't appear to be any blockage on the route from the poor flow tank. Can you help me find the cause?

 

[vyv_cox]

I believe the 'pressure equaliser' is an accumulator? Pressurised water systems will work perfectly well without one, in fact my boat was built without one and was more than ten years old before I fitted one. So whatever is causing one tank not to function correctly, it is not the accumulator. I suggest you check all the hoses for kinks or blockages and maybe back-flush from the Y joint where the two supplies join.

If your accumulator is the type that has a diaphragm in it there will be a schrader valve on the top. This can be pressurised with a bike pump to achieve the best efficiency = pump running the least when a tap is open. If it is the closed type you need to empty it, reconnect the supply and turn the pump back on.

 

[David2452]

If it's the small white plastic Comet equiliser it may have a crack in the upper area allowing air out (and in), you should be able to see water in it as they are translucent, generally if it's about 2/3rd if the way up with pump on and taps off then it's OK but if full then it may have a leak however small, if empty the Tee is blocked, I'm sure it is fitted as it should be but for clarity the inlet should be at the bottom, they are self pressurising and non adjustable.

 

[nlawley]

The equalizer is almost full (about a centimeter of air only at the top). Does this mean it has a crack? Have you any idea why one tank works with good pressure and the other has low pressure?

 

[David2452]

The equalizer is almost full (about a centimeter of air only at the top). Does this mean it has a crack? Have you any idea why one tank works with good pressure and the other has low pressure?

It may mean that but I would release the pressure and empty it first, then refit, only way to be sure is pressurise and immerse it which was how I have discovered leaks before, though if there is at least some air a leak is unlikely. If it does need replacing then use a small 2l bladder type, they are much better. I suspect, like Vyv that the two matters are unrelated and there is a small blockage, or rather restriction somewhere.

 

[nlawley]

I bypassed the equalizer and the problem is the same; normal pressure from one tank and low pressure from the other tank. (the lack of an equalizer didn't appear to make any difference to the system!) I checked all the hoses with washing up liquid and didn't find a leak. I'll try backflushing as Vyv suggested, there is also a small filter just outside the tank so I will check that also, when my tank is more empty.

 

[David2452]

It wouldn't, coz it aint working with only 10mm of air at the top. The ratio of air compressed to free air at say 3 bar is around 4 to 1 hence my comment that the equalier should have about 2/3 of its volume in water and about 1/3 in air assuming around a pressure of 3 bar, lower pressure pumps should leave more compressed air. However I believe the two faults to be unrelated and am pretty sure there is a restriction in the pipework or tank outlet.

 

[nlawley]

I backflushed and after this there was a lot of air in the pipe from the bad tank, which doesn't reduce.

 

[rogerthebodger]

You could have a small air leak into the suction side from the bad tank only. That would tend to reduce the flow but would show as air coming out of the tap when that tank was being used

 

[nlawley]

Problem solved the air was getting in at the joint I split to backflush. Both tanks are running beautifully now thanks for the help Vyv and David!!!