Water Pressure (accumulater) Tank Bladder

[Triskele]

What is the purpose of the bladder in a water pressure tank? Does it prevent the pump from cycling? My pump cycles on and off between 40psi (on) and 60psi (off). The accumulater pressure is set at 12 psi. According to this link, http://www.sta-rite.com/resources/images/13433.pdf,the bladder pressure should be set 2psi below the cut on (in my case 40 psi) pressure. I could not tell any difference in my system with the bladder pressure set at 12 psi or 38 psi. Perhaps it is not working? I was not able to change the cut on and off switch settings by adjusting the spring pressure. Had no effect on cut on and off pressure.

 

[SKYCHENEY]

Yes, the bladder keeps the pump from cycling as often. Check to make sure your bladder is not water logged. If the bladder has a leak, it will not hold the proper pressure. If you let all of the air out, you should not get water out of the schrader valve. If you do, then you need a new tank.

 

[SEVEN]

Dead on Sky. It can also make the water smell and taste bad. The water has to be on the outside of the bladder not the inside.

 

[oscarvan]

X2 Sky.

 

[MikeP]

Did the problem just start or has it been that way for some time?

As you found, the accumulator pressure should be set at or a couple of PSI below the pump's cut-in pressure. Check/adjust the accumulator pressure with the pump off and zero pressure in the water lines (faucets open, no water coming out). To clarify, you said it doesn't matter what the pressure is as far as pump operation...Did you check accumulator pressure with NO water pressure in the system? If you have the pump turned off/faucet open/system water pressure zero, can you charge the tank and will it hold pressure? If the bladder is ruptured, it will hold no pressure at all. Also, as noted, if the bladder is ruptured and there is water pressure present, you may get water out of the Schrader valve on the tank. BUT you might not because the tank may never actually fill with water even with a ruptured bladder because there is air in the upper part of the tank that simply gets compressed by the water. SO...it's possible to read some pressure on the tire gauge that is the result of the air in the tank being pressurized by the water.


FWIW, 40-60 PSI is pretty high pressure for the boat's system. I don't think that the OEM GM pump (if that's what you have) is designed to operate at that pressure level. This can contribute to the problem of rapid cycling. The OEM Hatteras recommendation is 20-30PSI. If you have an aftermarket pump, obviously, that does not apply and the manufacturer's recommendation for pressure should be used.

Pressure switches come in several ranges and there are some that you can individually adjust low and high pressure but they are expensive and not really necessary. the most common ones are something like 20/40, 30/50, 40/60. Typically, you can adjust the range somewhat but you can't vary the difference to any noticeable extent. IOW, you could adjust a 20/40 to say, 25/45 but you can't change the 20PSI range.

I suggest you check the tank to verify it will or will not hold pressure. If it does, and there is no change in operation, then I suggest you go to a 20/40 switch and after verifying the switch's/pump's cut-in pressure, set the accumulator to that pressure.

 

[dottieshusband]

Yes, the bladder keeps the pump from cycling as often. Check to make sure your bladder is not water logged. If the bladder has a leak, it will not hold the proper pressure. If you let all of the air out, you should not get water out of the schrader valve. If you do, then you need a new tank.

You can check to see if it's waterlogged by bleeding the Schroeder valve, if it spits water, you need a new one. They aren't expensive, maybe $130.

 

[SEVEN]

Go to Home Depot, they are half that cost.