Small blue tank...

[Skipperira]

Hello,

Nosing around in the pass thru...2006 dynasty I see a tank mounted below the water pump and cannot figure what it’s purpose is.

Any advice and does it require any servicing?

Thank you

 

[Babylon5]

It's called an accumulator. It's a tank that fills with water under pressure, and that water pressurizes a gas or a spring, and this pushes back on the water in your system so your pump doesn't have to.

Most systems (when on and not connected to city water) detect a lower water pressure, which causes the pump to turn on and re-establish the higher pressure. Once the pump has gone over the threshold of highest pressure, it turns off. Behind the scenes, the pressurization process pushes water into the accumulator, compressing the gas inside -- remember that liquids (generally) are incompressible, so the pressure goes into the accumulator until it is also pressurized, and at that point the threshold is reached and pump turns off.

When you need just a little water, the accumulator provides the pressure to push the water in the pipes to your faucet. When the accumulator is emptied, then once again the pressure falls enough to signal the pump to start again.

That's what an accumulator does.Here's a cool article that talks about how accumulators work in hydraulics, but achieves the same thing.

 

David

Edited May 1, 2021 by Babylon5

[Testdepth]

If one end is hooked to the water system and the other end has a valve cap identical to a tire, it is your accumulator tank which maintains water pressure and keeps your water pump from cycling so much.

[JDCrow]

Like a pressure tank on a well? 

[Mel S - '96 Safari]

1 hour ago, JDCrow said:

Like a pressure tank on a well? 

Exactly 👍

[Skipperira]

Thanks guys, that settles it

[Donflem]

I am replacing mine tomorrow should be easy to do.

[StephenW]

The pressure tank can  be checked by turning off the water pump and opening a faucet to relieve the pressure in the water system and using the tire valve on the end of the tank and using a pressure gauge to check the tank pressure.  The air pressure should be below the cut-in pressure of the water pump, which is 25psi.  Usually the air pressure should be between 18 to 22psi.   It's best to use a gauge that has a low range to get an accurate air pressure.  Be very careful using compressed air as over pressurizing the tank could damage the bladder inside.  In my working years I would use a manual type bicycle pump to fill the low pressure tanks.   If you can't get the tank to hold air pressure you most likely have a damaged bladder and need to replace the tank.  Good luck.

Stephen W    2001   Dynasty