Air coming out of water faucets

[tonykaralis]

I have recently replaced my old water pump with a new one(floking 12v 30psi), i connected up a new 2L water accumulator just after the pump, which i have pumped up to 30 psi and its not doing its job. I believe i have to pump somemore air in to it. Unfortunately due to the length of my boat i have A LOT of piping,7 cold water faucets and 7 hot water faucets. I have looked for hours trying to find a leak and havent found one. I have tried to purge the system of the air by going to the furthest tap from and the pump and letting the water run for 30 seconds and then another 30 seconds,i have done this to all of them. They work fine when being used quite often,but if i leave them unused for a couple of hours and turn on the tap on bursts of water come out,the pressure drops and then slowly builds up to what i consider normal tap pressure on a boat.. if anybody has any ideas as to what is going on with my water system,it would be a life saver as i have been fitting this water system for over 2 months. every time i fix something in the system another problem arises!

 

[Mrnotming]

Water system

Hi Tonykaralis,

Just to start the ball rolling so to speak!Others will contribute soon!

The pressure reservoir is there to maintain a head of pressure when the pump is off.

So it does this until a leak somewhere exhausts its effect?

Presumably the pump has valves which prevent backflow into the tank thus maintaining the head of pressure whilst inactive?

It may be that there is a problem with the pump valves?

Perhaps there is another non return valve before the pump which is leaking back water pressure?

I am not sure where the airlocks in supply are coming from though!Seems like as the water flows back into the tank, that air is being drawn back in somewhere due to vaccuum being established?

Is there much height difference between the tank outflow and the height of the highest outlet (tap or shower fitting)?


Perhaps it is just stop start arrival of the water rather than air mixed in?

Sorry not to have a definitive answer.

 

[KellysEye]

There should be a non return valve between the pump and the pressure cylinder. If the system has one perhaps it is not working. If you have a calorifier there should also be a non return valve, it there isn't that could cause the problem.

 

[duncan99210]

The accumulator on my system doesn't have to be pumped up at all. In fact what happens is that it fills to about the 2/3 level with water as the pump works up to pressure, then switches off. When you open a tap, the water in the accummulator comes out through the taps until the switch on pressure for the pump is reached (usually about 28psi), the pump then comes on and maintains the pressure at about 30 psi. When the tap is closed, the pump continues to run for a short time as the accummulator fills with water until the pump switch off pressure is reached (usually about 40 psi). If you've pumped air into the accummulator so that water cannot enter it, then you've defeated to object of having the accummulator there and will get the symptoms you have described. Try running the system without putting any air into the accummulator and see what happens.

Accummulators in sealed heating systems, which do require pumping up, operate in a different manner, smoothing pressure peaks caused by pumps starting and stopping, which may have lead to the confusion.

 

[vyv_cox]

There should be a non return valve between the pump and the pressure cylinder. If the system has one perhaps it is not working. If you have a calorifier there should also be a non return valve, it there isn't that could cause the problem.

Sorry, not the case. There is no need for a NRV between the pump and the accumulator, the pump has a discharge valve that is exactly the same thing.

You only need a check valve before the calorifier to prevent hot water from releasing back into the cold water supply to the tap. From the OPs description he is some way off meeting this problem.

Here's a simple method to set the pressure on your accumulator. Let all the air out of it. Turn on a tap, upon which the pump will run continuously. Now pump air into the accumulator, upon which there will be delays in pump operation, as the accumulator begins to work. Keep pumping air, the delays will become longer and then start to get shorter again as more air is introduced. At this point let some air out again until the delay period is maximised.

 

[tonykaralis]

[[Presumably the pump has valves which prevent backflow into the tank thus maintaining the head of pressure whilst inactive?

It may be that there is a problem with the pump valves?

Perhaps there is another non return valve before the pump which is leaking back water pressure?

I am not sure where the airlocks in supply are coming from though!Seems like as the water flows back into the tank, that air is being drawn back in somewhere due to vaccuum being established?

Is there much height difference between the tank outflow and the height of the highest outlet (tap or shower fitting)? ]]


I also suspected a problem with the pumps valves so i installed a brand new NRV just before the pump with a piece of transparent piping to see if the water is emptying out, which it is not! i also cheched the connection at my tank for cracks or leaks but nothing. The maximum height difference would be about 1,5 metres. Would adjusting the built in pressure switch maybe solve my problem??