Water Tanks

RobDor · Veteran Member

Water Tanks

JeffRae · Guru

Hi RobDor,

When mains water is hooked up, Im guessing you dont need to use the water pumps ? - Correct

Use pumps when drawing from tanks ? - Correct

Also, does water mains go through the tanks or seperate route ? - Separate route

RobDor · Veteran Member

Thanks. One more, need pumps for the hot water ?

watsea · Guru

RobDor wrote:
Thanks. One more, need pumps for the hot water ?

Usually, if connected to town water, NO. Town supply pressurises the van's internal system and this pressure forces water though the cold water pipes and the hot water system and pipes.

If, you are running off the pump, the pump sucks water from the tank(s) and pumps water into the pipe systems, pressurising everything. So YES, to hot and cold water supply if running off the pump.

-- Edited by watsea on Sunday 4th of July 2021 11:26:22 AM

watsea · Guru

Hi RorDor,

Most caravan water systems are similar to the attached diagram.

www.pinterest.com.au/pin/332140541238276938/

Mamil · Senior Member

Here's another diagram that helps to explain the basics. Not mine, borrowed from the CaravansPlus website...

Water system.jpg

Peter_n_Margaret · Guru

We NEVER hook up to mains water.
Too many issues with failed pressure control valves which puts excessive stress on the plumbing and the HWS in particular. Expensive and inconvenient failures. Just fill the tanks as required and use the water from there.
Cheers,
Peter

laurieoz · Senior Member

Peter_n_Margaret wrote:
We NEVER hook up to mains water.
Too many issues with failed pressure control valves which puts excessive stress on the plumbing and the HWS in particular. Expensive and inconvenient failures. Just fill the tanks as required and use the water from there.
Cheers,
Peter

Me two

Laurie

RobDor · Veteran Member

Thanks very much. The drawings explained it perfectly, cheers

BaldEd · Veteran Member

RobDor:
You didn't state the brand of your caravan. If it is a new (rather than used) Jayco then it most likely will not the 2nd NRV depicted in the diagram posted above. Jayco tend to rely on the pump's diaphragm to act as a NRV. If any sediment/plumbing swarf gets stuck under the diaphragm (an not unusual occurrence) then mains water water can pass right the pump and fill/overflow the water tanks - as witnessed by water flowing out the tank breathers when connected to mains supply. Many owners of Jaycos fit a John Guest NRV (a) just after the pump if there is room or (b) just before the pump if that is the easiest place to access the pipes.

Tailor · Veteran Member

As BaldEd said, the new Jaycos rely upon the pump to act as a non return valve. In my experience this often fails, the shurflo 4009, unlike their other models is a piece of crap. 4 replaced in 5 years from internal leaks causing them to seize. I put a John Guest NRV into the line from the pump. No more problem.

As for never using town water: Replace the pressure control valve with a decent one like a RMC and problem solved.

Bill B · Guru

Tailor wrote:

new Jaycos rely upon the pump to act as a non return valve. I

Not only Jayco, many manufacturers save a couple of dollars by doing this

bruceg · Veteran Member

RobDor, just a little extra info for you.

* For town water you really should fit a (detachable) 2 or 3 stage bank of filters before the van's input, AND put a pressure reducer at its input. Why? Because water ain't always (good) water, and pressure varies greatly in small town installations from way too high to barely enough. Stage 1 is just a strainer, with the cheapest possible, throw-away paper filter fitted (or a hand-me-down second stage filter). Stage 2 is a proper particle filter and stage 3 has chemical treatment material (usually just charcoal to remove bad tastes). Under your sink you will have a 4th stage for potable (cooking and drinking) water. Do NOT drink the water from any other outlet !

* Most town water inlets have the non-return valve built in, you'll see acceptable pressure values engraved into them.

* Don't EVER rely on the pressure pump to work as a non return valve, fit another one on one side of it !

* Scale can form inside tanks, after the filters, so a strainer should be fitted ahead of the pressure pump.

* The little strainer/aerators on taps and will rapidly accumulate scale. Buy some spares for rapid swap while soaking clogged ones in vinegar to renew.

* If the tanks are slow to fill, straighten out and then relocate the breather lines from the top of the fillers to at least 300mm above them, vented to outside.

* Storage hot water heaters will ALWAYS burn out their electric elements if operated empty. There is an isolating switch next to the element, use it before draining the tanks.

* Finally the big gotcha in modern plumbing. A mixer tap can back-mix the hot and cold during use. Depending on the position of other taps before or after it, hot water can be pushed through it to cold water taps or worse, cold water can be pushed through to the hot water inlet of a shower. The most overlooked culpret is the combination of a mixer then a trigger on the outside shower.

ooo ooo, I just remembered another water gotcha for new van owners. Most cassette toilets are NOT plumbed in. The surrounding frames and underseat lip are its separate, built-in, clean water tank.

bye.

-- Edited by bruceg on Sunday 25th of July 2021 12:06:12 PM