watertank filling

Submitted: Wednesday, Feb 06, 2008 at 03:16
ThreadID: 124403 Views:4556 Replies:7 FollowUps:3
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What are the tips re ensuring the water tanks are actually full? They seem to be full, but aren't.
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Reply By: Tellem Bugrem - Wednesday, Feb 06, 2008 at 05:49

Wednesday, Feb 06, 2008 at 05:49
Hello MeGPeS,

Check out posting 4127 on the Owners Forum. The reason they aren't full is because of loss due to syphoning through the overflow outlet.

Post 4127 explains members experiences and how to fix the problem.

AnswerID: 574218

Reply By: The Hob - Wednesday, Feb 06, 2008 at 06:55

Wednesday, Feb 06, 2008 at 06:55
With all the experimenting going on about getting full tanks I still have a question.
Sorry if it is too obvious!

But how does air get in to replace the water drawn by taps. The tanks might need overflows but surely they also need ventilation to equalise pressure in the tank or the tank will collapse as the pump draws water out for showers etc.

Sealing overflows would make the tank airtight?????????

AnswerID: 574219

Follow Up By: Noosa Fox - Wednesday, Feb 06, 2008 at 14:59

Wednesday, Feb 06, 2008 at 14:59
You are absolutely right.

Some time ago I extended the overflow pipes to the side of the van and put taps on them as they were still below the top of the tanks. It stopped the water leaking out but you had to open the tap shortly after starting to use that tank. Not really much of a problem because once you had used some water it no longer leaked out.

The suggested modification on the owners section though doesn't really need a tap if the outlet is high enough so the venting problem is then overcome.

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FollowupID: 849274

Reply By: Willie - Wednesday, Feb 06, 2008 at 20:49

Wednesday, Feb 06, 2008 at 20:49
Mr / Mrs MeGPeS ,

A couple of months ago , there was a huge discussion on here about water tanks and breather replacements , after I asked a question about water saving shower heads . Lucky I printed it out as there was some great ideas .

But I cannot find it in the archives to direct you to it . Where has it gone ?

AnswerID: 574220

Reply By: Jimjan - Thursday, Feb 07, 2008 at 03:59

Thursday, Feb 07, 2008 at 03:59
Making sure the tanks are full in the first place is important. The only way I have found to do this is to fill until I hear water coming from the tank overflow. I have found that filling tanks is an art. I was shown a device that I copied that does the trick. It is a length of green water hose with a nylex fitting on one end to attach to the hose, on the other end is an irrigation system plastic tap and attached to this is a 30cm length if flexible clear tubing. Push the clear plastic tubing as far into the filler hole as possible (takes several tries) and then turn on the tap. If you don't get the clear plastic hose far enough into the filler hole then you will have water coming straight back out of the filler.


AnswerID: 574221

Reply By: Andy1 - Thursday, Feb 07, 2008 at 14:47

Thursday, Feb 07, 2008 at 14:47
I have been mulling over this & the associated thread relating to water tanks with some interest. In logic it would seem that if there is a tube on the breather vent that extends internally into the tank then no matter what you do with the vent you are limited to filling the tank the to about the lower level of that tube.

If there is no internal extended tube then there will be no siphon effect regardless of the level of the overflow tube.

If there is an extended internal tube it is pretty much impossible to fill the above the lower level of this tube because when the water level reaches the bottom of such a tube, if it exsts, the tank will only vent water regardless of the height of the external breather.

Does anyone know, with certain knowledge, if the breather is just on the top of the tank or extending down into the tank?

AnswerID: 574222

Follow Up By: Turist - Sunday, Feb 10, 2008 at 01:06

Sunday, Feb 10, 2008 at 01:06
Andy I had to remove the rear tank to repair a leak.
The leak was from the top of the tank, a screw had penetrated through the floor and punctured the tank.

When I dropped the tank out the breather hose fell out, it was held in place only by Sikaflex which does not adhere very well to the poly tank.

The breather hose extended about 75mm into the tank in a curve downwards.
I would estimate that the lower portion of the hose was about 50mm down from the top of the tank.

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FollowupID: 849275

Reply By: Andy1 - Sunday, Feb 10, 2008 at 14:31

Sunday, Feb 10, 2008 at 14:31

If this is standard then filling the tank to 100% of nominal capacity will never be possible.

AnswerID: 574223

Follow Up By: Turist - Monday, Feb 11, 2008 at 01:32

Monday, Feb 11, 2008 at 01:32
I went back to BT with this comment and was advised the it must have been an isolated case, never heard of it before.
(But then how many have removed a tank and checked?)

I think the only way to check the tank volume is to fill it then drain and measure.
I am sure that we have one tank that is not filling to the max as it empties much faster than the other two and our use is constant.

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Reply By: Deleted User - Monday, Feb 11, 2008 at 17:32

Monday, Feb 11, 2008 at 17:32
Howdy All.
When I fitted two extra tanks I removed the existing tanks and decided to replace all the vent pipes. Instead of using the curly PVC pipe. I used 12mm thin wall aluminium tube as the tank vent. I used 12mm garden hose and took all the hoses out to six LP valves positioned just in front of the off side wheel. During this process I almost completely replumbed the van and fitted home made copper elbows and Tees in place of the LP irrigation fitting that BT use....they don't leak.
The aluminium vent tube has a slight curve down to enable the flexible hose to be sipped over the end. No need for hose clips as it is a snug fit. These hoses are saddled onto the ply floor and carried over the chassis to the valve assembly. This method makes it more convenient to fill the tanks and also drain them as the curly water trap BT uses prevents draining properly.

Pouring rain here...had at least 100mm in the last couple of hours. The creeks are running a banker and our crossing has 600mm over the top so we are isolated for a while.
Haven't seen a wet season like it for years. Amazing what a change of government can do.
cheers and beers

AnswerID: 574224

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