Filling Water tanks

Branchie · Senior Member

Filling Water tanks

yobarr · Guru

Branchie wrote:
Hi all, I have attached a device I have found on the net to fill the water tanks on my van. The gauge reads the litres that flow into the each tank. I have 1 x 95 ltr tank with a single fill point, and a 2 x 95 lts tanks that fill from their own fill point (connected to each other).. The issue I have is that i can only get a max of 60-65 lts in the single tank and 110ltrs in the twin tanks, as water then begins to overflow from both the fill point and the breather outlets.. I have tries filling all tanks very slowly, to allow the air more time to escape, but it makes no difference.. The other option I have not tried yet is to fill from the drain outlets to see if that makes any difference, (but i should not have too).. Anyone know of another way, to get the tanks to full capacity../
-- Edited by Branchie on Friday 10th of January 2020 04:45:06 AM

My suggestion would be to get an empty 20 litre drum,use your gauge whilst filling the drum,and see how much water your gauge says has been used to actually fill that tank.This will show whether the gauge is anywhere near accurate.Next I would measure the external dimensions of your "95 litre" tanks and calculate how much water should be needed to fill that tank.....obviously the external dimensions are greater than internal,and allowances need to be made for rounded corners etc etc. That will give you a pretty good idea whether the tanks are indeed 95 litres? If water comes out tge breather and the fill point,I would expect that the tank is full? Good luck.Cheers.

iana · Guru

There would be three ways to determine the capacity of the tanks. 1/ measure the outside dimensions and multiply, good theoretical capacity for salesmen. or 2/ stand the tank on its end with the outlets blocked off and fill with a measured quantity, this gives the capacity of the tank. But 3/ to get the "usable" amount the tank holds, you need to fill the "installed" tank above the outlet, start up the pump and pump out the tank until the pump looses its prime, this is done with the van level, now fill the tank until the water comes out the breather, this is the usable quantity for the tank, and can vary substantially from those other measurements.
I find water trapped in long breather tube runs, can give a false indication that the tank is full.

Tony Bev · Guru

I can only speak of the original potable water tank, in my 2006 Jayco Conquest

It is supposed to be 80 litre capacity, but when I look underneath the motorhome, and follow the filler and breather lines, it will be impossible to completely fill it

Below is a rough sketch of why I can never fill it

In my opinion if I wanted to completely fill my original water tank, I would need to place the breather hose, at the top of the tank

Water tank setup.png

dieseltojo · Senior Member

Water can only come out of the breathe on three occasions.
1... You have a small amount in the air line and it will be expelled during filling by the incoming water pressure.

2... You have filled the tank as much as it will hold.

3... It could be that some ham fisted fool has made the air point the fill point and the air vent pipe comes off the actual water inlet point. In other words reverse connected. Then the vent would be lower.

If you look at Tony's illustration the air relief is always higher than the inlet point. If water comes out the air inlet it is self evident that it has come from its highest point.

I do not trust any measuring device on a small capacity basis. I once was in Cooberpedy and paid for a 20 litre can of water at a paid outlet. They got their $1.00 or whatever I got 12 litres of water.

That folks is a great little business. smile

-- Edited by dieseltojo on Friday 10th of January 2020 05:00:19 PM

Tony Bev · Guru

To answer this part of the question

Anyone know of another way, to get the tanks to full capacity../

Here is how I have improved my situation, I am sure others may have a better method than me

It does not completely fill my original tank, but it makes life easier for me

I fitted a second tank and placed both the filler and breather hoses at the top
I then connected a hose from the bottom of the new tank, and fitted it to the bottom (drain) of the original tank

I now connect my food grade 1/2 inch hose from a tap, and just turn the tap on, (and then hurry up and wait)

The filling water goes through a (Bunnings) 1/2 inch manual valve, and a 1/2 inch one way valve
I leave the manual valve open, as it is only there if the one way valve fails

I notice as I am filling the tanks, that the water first starts coming out of my original filling hose, then out of my original breather hose
Before it finally come out on my new breather hose

Perhaps the rough sketch below, will explain it a bit better

Water tank setup.png

diggerop · Senior Member

I have one of those meters, I know that it is inaccurate as we checked it one time. It proved itself again to be very inaccurate just a few days ago when I completely emptied the tanks and refilled them. It told me that 103 litres fills to over flowing two tanks totalling 180 litres. Hah ha, I wonder why I even still have it.

pitch1 · Newbie

can i ask what brand your tanks are?

Branchie · Senior Member

Not sure of the brand of tanks, will have to look hard under the van as they are encased in sheet metal for stone protection..

Yes the water does come out of the breather hole (as well as the fill point, but i would not have thought the meter would be that far out.. But will definitely have it checked against a 20ltr gerry can, when i get home..

Thanks again all for your comments and suggestions..

Safe Travels..

yobarr · Guru

diggerop wrote:
I have one of those meters, I know that it is inaccurate as we checked it one time. It proved itself again to be very inaccurate just a few days ago when I completely emptied the tanks and refilled them. It told me that 103 litres fills to over flowing two tanks totalling 180 litres. Hah ha, I wonder why I even still have it.

Sounds to be about as accurate as figures given by many towball scales,when compared with accurate readings from bathroom scales.Cheers

dieseltojo · Senior Member

Yep it is hard to let go of an idea...... smile

Clean it up and give it as gift to someone you don't really like..... smile

Onedodger · Guru

I suggest you go with your original thoughts.

I put a T piece in the pick up line from my tanks before the pressure pump and ran a line to the outside of the van with an in line tap I could easily reach and fitted a snap fitting on the outside end where a hose can be attached. To fill one only has to turn the inline tap on attach hose then open the filler caps turn on the the garden hose and wait until water comes out the filler point. This way the tanks are filled to the max each time and without any air locks. Then turn off the inline tap and the hose disconnect.

StewG · Senior Member

Similarly to Dodg, I changed the tank input so that I could fill the tanks via the water (mains) inlet rather than through the key lock filler caps on the side of the caravan. This means I can selectively fill each of my two fresh water tanks by turning a couple of taps from inside the van and watch the gauges or listen for the overflow to know when to close off the taps. It took a while to work out the best way to achieve it, but it works a treat and I no longer need the external fillers.
If caravan makers incorporated this in their designs, they could save quite a few dollars in parts and labour while making the van/motorhome simpler and more convenient for the purchaser.

Hylife · Guru

Sounds to me like the old issue of many owners believing they have 95L tanks when in actual fact they only have the more common 65L tanks.

Brodie Allen · Guru

The best little device that I have added to the van.

Easy to calibrate, and is very comforting to know exactly how much is left.

Accurate to the litre.

here's where I got mine - were so helpful, especially when I realised that I
had made an error and they assisted without question.

suncoastcaravanservice.com.au/product/topargee-flush-mount-water-tank-gauge-rv-1-4-mt-extension-lead-caravan-boat/

More info:

www.topargee.com.au/water-tank-gauges.html

www.fullrangecamping.com.au/shop/product/topargee-water-tank-gauges/

Brodie