Thread: Water tank. Divert water to mains.

Tourgy,
simplest way would be to have a "Y" valve on the outlet of your pump. Pump runs into one leg of the "Y" and a line from your mains into the other. When your tank runs low it's just a matter of switching across to your town water supply.

Mick

If you are going to the trouble of getting a tank then I'd suggest getting that electonic diverter. Doing it manually would be a pita.

Get a good pump too. Not a cheapy. I have a 2200L tank and a Davey pump which is very good. We live on a sloping block so watering the garden with the tank water means the pump is forcing the water uphill, which a good pump will do easily.

I haven't got around to using the tank for the toilet yet. We are happy enough using it to keep the gardens watered and the cars clean.

It not only depends on the size of the tank but also the area of roof you can use as a catchment. I doubled the roof catchment area recently which means I can use the tank water more often, knowing one good downpour (we wish) will fill it again. I've estimated I have about 65 - 70sqm of catchment area so 1ml of rain gives me 65 - 70L and we get a full tank for every 30m of rain.

The pump puts out around 6L per minute so a full tank gives us about 6 hours watering. I reckon we can go for about 5 -6 weeks without any rain and keep the garden alive. I think we'd need a bigger tank, or a second one, to be able to use the water inside. I'd also think it would need some sort of filter if it was going to the washing machine. (Ours is a front loader as well - they use so much less then top loaders)

I have a neighbour with the same size tank but he tends to hoard the water rather than us it. I can't understand that thinking. If it looks like it's going to rain the the next 24 hours, i get out and water the garden so that I creat storage space in the tank. That way, the new rain water is collected, rather than having it just run out the overfolw pipe and back down the drain.

In regard to your checking valve you can set it up as Mick has suggested. This stuff is not rocket science plan it on paper and get advice from a knowledgeable friend or three.

More tanks more tanks more tanks has to be the mentality these days.

Pete

Originally Posted by journeyman Mick

Tourgy,
simplest way would be to have a "Y" valve on the outlet of your pump. Pump runs into one leg of the "Y" and a line from your mains into the other. When your tank runs low it's just a matter of switching across to your town water supply.

Mick

Thanks for the quick response blokes.
journeyman Mick, this sounds like a simple solution. I think I can see what you mean. I have never been involved in doing any handyman stuff before so I have to rely on the tradespeople that I use. I'm sure I told the plumber cleary yesterday what I wanted, but he seemed to want to go with the electronic option.

Originally Posted by Gumby

If you are going to the trouble of getting a tank then I'd suggest getting that electonic diverter. Doing it manually would be a pita.

Gumby
I woukd love to go this way but am keeping my options open for a less expensive way out. I can see what you mean about it being a pita, having to check water levels regurlarly etc but if it saves me a few bob then I am happy to go this way.

Oh, and since you mentioned that the laudry water may need to be filtered I may give it a miss diverting to there. I'll see what the plumber who eventually does the job have to say about it.

Cheers
tourgy

EDIT: what about something like this? Is this what I am after? Or is the "Y" valve otion the simplest solution?
http://www.waterstore.com.au/display_details.asp?id=1

Basically use a float valve inside your tank set at 10% of your tank volume
You must protect the mains supply from cross contamination with a backflow valve
Run the outlet of the float valve up to 100mm above the tank full level to prevent syphon
Use ballvalves between all of your main items, Including the backflow valve to make maitenance easier ( you dont want to drain the tank to do maitenance)

When the tank is full to above the float valve it will float and stay off.

Occasionally move the float valve with a broom handle or something to make sure its not jamming ( every 6 months) Check the operation of everything else at the smae time as routine maitenance.

The whole set up can be done with standard ( read cheap) fittings and valves the most expensive is the backflow which i think is around $40.

You must put a backflow valve in before the connection to protect the mains.

If youve got any questions just post em here and ill try to answer them, I know the drawing is hard to read

Cheers, bricks.

I bought one of those float valves from a garden watering system supplier in Springvale Rd a few weeks ago - cost all of about $20. (I'm not tying into mains, so didn't need the backflow vv, but even they were pretty cheap for brass ones - looked good quality.

Originally Posted by bricks;

[U

You must put a backflow valve in before the connection to protect the mains.[/U]

Cheers, bricks.

Didn't think you needed a BF preventer if you left the appropriate air gap between the the inlet feed pipe and your overflow level.

That would be logical but I think bricks is right. That's what I've always been told by my old man. I suppose if the overflow blocked up you could end up with water from the tank in the float inlet. How it would get through the valve and into the mains, I don't know...

Silent the theory goes that if someone drained the main for maintenance you could get backflow....but I guess it is very likely that you could get backflow into your own domestic lines if the right set of surcumstances presented themselves.

I also thought that there was a requirement that the BF be placed valve higher than any end break so Bricks sketch would be better if the inlet pipe fed from the top of the tank above the water level with the BF valve up at that level?

Back flow can happen if the fitting inside the tank leak/corrode and the main syphons, ( i try to get plastic for inside the tank if i can, forgot to say that before).

Bleedin You can get a "vacum breaker" for the end of the feeder tube if needed, but because mains are pressurized and the backflow is spring loaded IMO it can go anywhere because it works on negative pressure on the inlet side.
If the Air gap isnt included aswell as the Domestic backflow valve ( $33) then I think the hazard rating for the system goes to High hazard , Dual Check testable devices are required then ( $250) and need to be registered and inspected every 6 months in S.A. Plus two is better than one any way IMO.

Even if you may have backflow at your boundary IMO it is a good idea to protect yourself from your own tank ( read- dead possum, fungus, mould, neigbours cat, Bird dropping on roof flushed into tank Etc).

PS does anyone know of a ball float that has the feed tube on the outside of the tank??? would help with maitenance.

I read a very easy cheap and almost maintenance free system. It has the capablity of feeding your complete water requirements including hots water. I will attempt to describe in order.

From mains >backflow valve >variable pressure reducer > T junction (one coming from mains, the other side going to tank side and the middle going to house feed main feed.

From tank >pressure pump connected to float sensor >backflow valve >above mentioned T junction

Ok here is how it all works. Once connected, reduce the variable pressure reducer until the pump starts to kick in and leave at that point and thats it!

The way the system works is while there is water in the tank, the float sensor will allow the pump to fire up when any house tap is turned on. If for any reason the pump does not turn on due to lack of water or busted, all water will be drawn from the mains. While water is available in the tank and the pump is working, all water will be feed from the tank.

If your stressed about feeding drinking taps etc from tank water, install some cartidge filters on the tank side before the T junction and replace them every so often.

Why do people stress about drinking tank water? I've got nothing else to drink and it hasn't killed me yet.

I like that set up jimc, except that you are throttling the mains water pressure back to below that of the pump, so you'd better make sure it's a good pump.

I dont want to argue Jimc, In my opinion that system is more complex and costly than it needs to be.
There seem to be too many rather expensive and critical devices installed, to allow simple, long term, maitenance free operation.
The backflow rating for the unit (if installed in S.A.) will be High hazard - read expensive valves, and costly maitenance.

In my opinion keeping things simple, using standard fittings and pumps makes for a more reliable and self servicable unit. Most importantly self servicable.

Personally I'd go with something like that thing from The Waterstore....
(http://www.anadexlabs.com.au/float_based_dual_water.htm) except that I'd be trying out making it myself using a standard float valve.

Take the ball off the end of a float valve and attach a length of string to the ball. Tie the other end of the string to the end of the brass rod on the float valve (where the ball used to be). Get a light stainless steel spring attach one end to the roof of the tank and the other to the brass rod - tension on the spring should be enough to keep the valve closed when there is no weight on the string (ball floating) but not enough to keep it closed when the ball is hanging off it. Instead of $143 plus postage it should set you back no more than $20.

By the by though........don't what ever you do buy a float valve from the site shown above!!!!
http://www.anadexlabs.com.au/shop/pr...age=2&featured

$129 for a 2" float valve!!!!