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Your RV water pump’s job is to keep the pressure stabilized within the water system, so it will cycle on and off whenever you open a faucet or flush the toilet. Water pumps can be noisy, especially in the middle of the night when someone uses the toilet. A water pump accumulator tank will help to hold the water system under pressure, which means the pump won't have to run as often. Over time, the accumulator tank can extend the life of your water pump, because the pump will cycle on and off less often.
How the Tank Works
The accumulator tank has an internal bladder that stores air, holding water in the tank and in your water system under pressure. When a faucet is opened, the water from the accumulator tank will be used first. When the accumulator's storage tank is exhausted, the water pump will turn on to maintain pressure in the water system.
Where to Locate Your Tank
There is no need to mount the accumulator tank right next to the water pump. It can even be located some distance away, where you have room and easy access to it. Just be sure to install the accumulator on the outlet side of the water pump, not between the water storage tank and the water pump.
Mount the accumulator tank vertically, with the air valve up. This makes it easier to check the amount of pressure in the system, and to recharge the accumulator tank with air as necessary.
You can install the accumulator in-line, using the inlet and outlet sides of the accumulator, or with a "T-fitting" off of the water line, capping the outlet side of the accumulator. The accumulator tank will still fill with water and hold pressure in the system, even if it isn't mounted in-line.
Before installing an accumulator tank, be sure to turn off the water pump. Also make sure you're not connected to "shore water,” bringing water into your RV from an external source.
Use water tubing and hose clamps, or braided flexible tubing such as that used to install sinks in homes. You may find it easiest to install the hoses to the accumulator tank first, and than install the accumulator onto its supplied bracket.
If using standard water hose, cut the water system hose on the outlet side of the pump, and slip a hose clamp over each end of the hose. Tighten the barbed fittings into the accumulator tank, first wrapping them with Teflon thread tape. Push the hoses onto the barbs, and tighten the hose clamps.
If using braided flexible tubing, get the correct adapters when you purchase the braided tubing. Install the adapters into the accumulator tank, again using Teflon thread tape. Then tighten the flex tubing onto the fittings.
Precharge the accumulator tank with air using a standard Schrader air valve, the familiar type of valve used on bicycle and car tire tubes. Before using your new accumulator tank, check the pressure at the valve with a air pressure gauge. Most systems are set to around 20 lbs. per square inch (psi). Follow the manufacturer’s suggestions, and pressurize the tank if necessary.
Turn on the water pump and check for leaks. Your water pump should run long enough to pressurize the system and fill the new tank, and then remain off as your accumulator tank fills the demand for water and keeps the system pressurized.
Based in central Oregon, Gary MacFadden started writing in 1972 as a "stringer" for several Montana newspapers. He has written six books about bicycle touring and has been published in "Outside," "Wilderness Camping," "Adventure Cyclist" and other publications. MacFadden holds a Bachelor of Arts in journalism from the University of Montana.