# Water Pressure Tank



## s'more (Jun 8, 2005)

I'm going to add the water pressure tank to the cold water line, on the pressurized side of the water pump. Here are my questions;

1. Is a "Hot water expansion tank" the same as a "pressure tank"?
I purchased the 4 gallon Hot water expansion tank, with the diaphragm, because I couldn't find a pressure tank in the same price range that was less than mega-gallons. They seem to be the same product with different names.

2. Is there a pressure setting on the pump that needs to be adjusted after the pressure tank installation?
The tank is pre-charged at 40 psi. Is that too high?

Thanx guys, Mark


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## Insomniak (Jul 7, 2006)

s said:


> I'm going to add the water pressure tank to the cold water line, on the pressurized side of the water pump. Here are my questions;
> 
> 1. Is a "Hot water expansion tank" the same as a "pressure tank"?
> I purchased the 4 gallon Hot water expansion tank, with the diaphragm, because I couldn't find a pressure tank in the same price range that was less than mega-gallons. They seem to be the same product with different names.
> ...


You got exactly what you need, and what I and a lot of other people have used. You just need some fittings to tee into the water line after the pump.

You should set the pressure in the tank to a couple psi less than the turn-on pressure of your water pump. For most Shurflo pumps, that's around 26-28 psi, so you would set the tank to 24-26 psi.

You can determine your exact pressure after you install the tank. Take the air in the tank down to about 22 pounds. Purge the air from the system and let the tank fill up. Open a faucet and keep your other hand on the water pump switch. As soon as the pump comes on, turn off the switch and measure the pressure in your tank. Reset the air to a couple pounds lower than that reading, and you're set !!

Too much pressure in the tank and it won't hold much water. Too little pressure and the pump runs longer when it comes on. You should find a good medium.


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## BoaterDan (Jul 1, 2005)

Aren't these most commonly called accumulator tanks? Or is that something different?


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## CamperAndy (Aug 26, 2004)

BoaterDan said:


> Aren't these most commonly called accumulator tanks? Or is that something different?


Just one of several names, also they are called "surge tanks". The main characteristics you need are that it must have a diaphragm and it must have an adjustable pressure.

Insomniak had it nailed on where to set it (1 to 2 psi below the low pressure switch), I just use a digital tire pressure gage on the tank and watched the pressure fall until the pump kicked on. Then once you know the pressure and this part is important. Turn the pump off and drain the rest of the water from the tank. Now with the diaphragm fully extended, check and adjust the air pressure to 1 to 2 psi below the low pressure switch. Use a marker to write the set pressure on the tank and then you will not have to remember it.


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