I have a Well-Rite pressure tank (1994) with a submersible pump. The pressure tank has a bladder. This bladder appears to be loosing air. I have replaced the valve stem and valve – to no avail. Water does not come out of the valve when it is depressed. I charge the bladder to about 30 psi every 3 weeks. Do I have to replace my tank?
If the system is under pressure then it reads aobout 30 psi. When I take the pressure off the system (turn off the pump and open a tap) the pressure will be very low – will not read on my pressure guage – but there is usually some air pressure left. I usually charge the tank when the pump starts running to much. This cures the problem – for a while.
The only way an expansion tank can drain is for air behind the bladder to push it out. If your tank does not drain completely than it does not have enough air in it to displace the water inside. You should be able to easily move the tank empty.
To drain an expansion tank
First you need to drain the tank as far as it can go by itself. Next using a bicycle tire pump fill up the tank only until the water begins to flow out. Do not over pump the tank or you may ruin the bladder. Keep doing this until you are sure all of the air is out of the tank. Now to obtain the proper air pressure this can only be checked with the tank empty. Fill the tank up with 2 psi below the start of your pressure switch. (Example 30 psi on means 28 psi in the tank.) Now it would be a good time to disinfect the tank with some bleach. Use an empty filter sump housing to introduce about a 1/4 cup of bleach into the tank you will need some valves to do this. Now rinse the tank by filling it and draining it several times.