Pressure vessel problem

[Wild at heart]

The pressure vessel switch stopped working and the pressure vessel tank was full of water ( but no water coming out the taps in house ) so I did the following:

Turned off Elec supply,
Turned on taps in house and used a compressor to blow the water out of the tank
Air pressure was low so increased it to 58 psi as the cut in/off is set at 60/80
Changed pressure switch
Turned off taps in house
Switched Elec supply back on and put the pump back on.
Pressure went upto 80 and cut off, turned taps back on/off to check it cut in again at 60 which it does.
Water pressure in house is correct.

Problem is that the pressure vessel is empty of water ( never filled when I turned the pump back on ) but pump is cutting in/ out as it should be at 60/80 and the water pressure in the house is correct.

Only thing I forgot to do when turning the system back on was to shut the valve for the presure tank so basically I didn't build the pressure up in the tank before letting the water back into the house!

Is that what i have done wrong? or is the problem something else??

Any help would be greatly appreciated.

 

[LLigetfa]

Problem is that the pressure vessel is empty of water...

A properly functioning captive air tank should not be full of water. It should not have any water at all in it at 60 PSI, and only a small amount of water in it at 80 PSI. When precharging the air, make sure the air pressure gauge is calibrated to the water pressure gauge. The two gauges should read close to the same whenever the pressure is above the cut-in.

 

[Sponsor]

 

[Wild at heart]

A properly functioning captive air tank should not be full of water. It should not have any water at all in it at 60 PSI, and only a small amount of water in it at 80 PSI. When precharging the air, make sure the air pressure gauge is calibrated to the water pressure gauge. The two gauges should read close to the same whenever the pressure is above the cut-in.

Its set at 60/80 because the water has to be pushed up quite a steep hill to the house.

So what you are saying is that the air pressure gauge and the water pressure gauge ( I assume you mean the gauge at the top of the tank ) should both have the same readings? ie the air one says 58 and the water one should also say 58 at the same time?

On the water in the tank, before I had the switch problem it was impossible to lift the tank due to the water in it, now you could pick it up and walk off with it.

My only concern is that with no water stored in the tank it will mean the pump is starting more often than it should be but its defo cutting in/out at 60/80 as it should be.

Thanks for your help, its much appreciated.

Its a 200 litre tank btw.

 

[Wild at heart]

Would it be safe/ an accurate reading to take a air gauge reading without turning off the pump/ draining the system first?

( just to check the two readings are similar and there isn't too much air in the tank )

 

[LLigetfa]

So what you are saying is that the air pressure gauge and the water pressure gauge ( I assume you mean the gauge at the top of the tank ) should both have the same readings? ie the air one says 58 and the water one should also say 58 at the same time?

No, not at 58 PSI but yes at 61 and above.
Of course a waterlogged tank would be heavy since there is no air in it. Test how many litres of water you can draw from the tank after the pump shuts off to where the pump turns on again. That is the amount of drawdown available. Compare that with published specs or apply Boyle's law.

 

[Valveman]

Air doesn't usually get out of a diaphragm tank unless the diaphragm is ruptured. The tank will be waterlogged again very soon. The pump cycling on and off too much is why the diaphragm is ruptured. Like bending a wire back and forth until it breaks while the pump is cycling on and off repeatedly. With the right amount of air charge a 200L tank only holds about 40L of water. Your pump has already been "starting more often than it should be", that is what caused the ruptured diaphragm. Double the size of the tank cuts the cycling in half. Using a Cycle Stop Valve eliminates the repetitive cycling, and an even smaller tank can be used.