Water tank pumps....

The manufacturer I mentioned is at Pakenham, a bit far for you.


I still have no idea what they mean by "regulator" but I am guessing that they mean RainBank lol.

New home owners would save a lot of money if they had their plumbing done the way you have. Most plumbers (and others in the industry including some VBA 'experts') don't fully know the regulations.

Hi SaveH2O, just wondering who that manufacturer might be as pakenham suits me well
And please could you explain further what you mean by saving a lot of money for plumbing like that?

It is O.P.S. Country Tanks, 65 Bald Hill Road, Pakenham. I was going to link the site but there was a notice saying that the site could be hacked.

Re savings, people get ripped off big time on water tank plumbing to cisterns.

I posted a diagram earlier in this thread that showed an alternative rainwater diversion to the cistern whereby the rainwater supply had a separate line to a second cistern valve. The isolation valves on the wall are the manual changeover devices when mains water is plumbed separately to the other cistern valve. By doing this, you eliminate the need for expensive and sometimes unreliable electronic automatic mains water switching devices but new home owners are very rarely told of their many options and are over charged accordingly.

David does not have the mains water connected to the cisterns yet and it is my understanding that to also connect the mains water to the cistern for his situation, the mains water would need to be connected to the rainwater pipe. If this is done, then the mains water pipe would need to be fitted with a check valve downstream of the mains water - rainwater connection.

To switch the cistern supply between mains water and rainwater when the two water supplies share the same pipe, David bought a manual MainRain device that is fitted to a pump's pressure controller. David also linked the MainRain website earlier. The MainRain can be used with any pump fitted with a pressure controller.

Thanks very much SaveH2O
So, (and I hope I'm not hijacking this thread too much, please feel free to tell me to start a new one or something) if I'm still at the contracts stage of my build, is it best if I'm able to get the separate line to a second cistern valve? I'm hoping to have a small tank plumbed to 2 toilets and my fairly efficient front loader washing machine, as well as veggie beds in the back yard.
My builder has quoted me $3.5k for a 2000l tank plus plumbing which feels expensive to me, this is the pump they are planning on using: http://www.asctanks.com.au/product/zeno ... witchover/
Is that even an appropriate pump? Would I be better off with a pressure tank set up?
Thanks again for all your help, there are just so many things to learn about my poor brain is full so having someone simplify this is amazingly helpful

Most of the information you seek has been discussed in this thread.

There is a diagram of the twin cistern valve system on page one. The best cistern valve to use is the Fluidmaster 400UK063. This valve is compact because the float slides up and down the shaft. You will need to discuss this method during the contract stage. You do not need mains water check valves or the usual expensive automatic mains water switching device because it is a manual system.

http://www.vba.vic.gov.au/__data/assets ... sterns.pdf

The 750W 75 litres per minute pump you are to be given is far, far too big. Note that 75 litres per minute is straight from the pump and not through flow restricting pipes. A smaller more economical pump that won't strangle itself or potentially generate water hammer is the best choice. The Einhell that is mentioned in this thread is a very good price because it also comes with a 20 litre pressure tank. When the tank gets low and the pump kicks in, it will operate at peak efficiency.

If you need an outside garden tap, just make sure that a decent size hose or pipe connects the pump to the tap. If you need good pressure at the garden, just use an 18mm garden hose with a short length of 12mm hose attached to the end so you can attach the regular nozzles, sprinklers etc.

Make sure that the suction hose between the tank and the pump isn't fitted to the pump by a 90 degree elbow fitted to the pump. There must be a straight length of hose before the pump that respects 8 diameters.

Also make sure that the tank's outlet that supplies the pump isn't fitted right at the bottom of the tank as so many are...unless you want the pump to vacuum the tank's floor.

2,000 litres isn't a big tank but a colorbond slimline tank can be expensive. Poly round tanks can also have narrow diameters and two narrow diameter 1,000 litre tanks usually offer good savings plus they allow you to have a settling system that will deliver good quality water.

Also don't allow the plumber to uselessly fit a first flush diverter to the top of a vertical riser as most do. The Victorian regulations require a minimum 50 sq m roof catchment area to be harvested and this will entail harvesting 2 downpipes and having a vertical riser if a standard wet system is used.

Depending on the type of tank the builder has in mind, the $3,500 quote is less than most builders would charge, some would (unfairly) charge double that. With the right tank(s) and pump choice, your builder should be able to shave quite a bit off the quote and give you a better system.

Thanks heaps SaveH2O, I really appreciate the help
Final question if I may, the builder has said increasing the surface area of the roof that drains into the tank is just removing an extra downpipe... Is it really as simple as that? It just strikes me as being too good to be true..

I can hear them...



This is an overview of roof drainage regulations.

For eaves gutters, the roof area drained to each downpipe is determined by your area's 1:20 (year) Average Recurrence Interval (ARI) , the gutter's cross sectional area (carrying capacity), the downpipe size, the roof slope which factors wind driven rain and any abutting walls. Sydney's 1:20 year event is rated about 50% greater than Melbourne and Brisbane is about double.

Gutters are sloped (minimum slope is 1:500 or 2mm per metre).

Downpipes are fitted at the bottom of a slope (low point) and the roof area drained is dependent on where the gutter's high point is.

A downpipe cannot simply be removed because that would create a dam where the down pipe was suppose to be.

If the downpipes were moved further apart so as to avoid a dam (as would be necessary), the greater roof area(s) drained may no longer be compliant. It would also bean the downpipes being further apart and this would compromise the gutter slope.

The number of downpipes can be reduced if a larger cross sectional gutter is used. Depending on the increased gutter size and the roof areas harvested to the downpipes, the downpipe size may need to be increased.

If you opt for a 2,000 litre rainwater tank for the Victorian 6 star compliance, the house is required to harvest a minimum 50 square metres of roof catchment area. The term "roof catchment" refers to a roof area that has been factored for the roof slope. The standard roof slope is 23 degrees. When doing roof drainage calculations, the standard 23 degree roof slope is multiplied by 1.21 to allow for wind driven rain.

If a (Melbourne) house with a 23 degree roof was fitted with a 5,250 sq mm cross sectional gutter and either 100mm x 50mm rectangular or 90mm round downpipes, the maximum roof area allowed to be drained would be about 38 sq m. Multiply this by 1.21 and we get a roof catchment of about 46 sq m. As you can see, this would necessitate having two downpipes harvested to meet compliance and this in turn would me in most instances having one downpipe diverted to the tank through an underground wet system...and having all of the related problems later on.

You can have a single downpipe draining from a roof catchment area of =50 sq m by having a gutter cross sectional area of about 5,700 sq mm but because each roof catchment area will not be equal, you would effectively need a gutter cross sectional of about 6,300 sq mm. If the gutters are slotted, this is a BIG gutter.

You also have to consider where the tank will be sited, if the area is to be concreted, you really don't want to have an un-flushable buried wet system pipe like so many new houses have.

There are systems that get around the standard problems but this is your answer to your immediate question.

Thanks again SaveH2O. I thought I could hear those alarm bells ringing... The builder seems to be good with the standard stuff, but anything extra seems to get thrown in the too hard basket and it looks like they're not interested. It was basically I won't need it for the 6 star rating so who cares...
So thanks again for reassuring me that I'm not going completely crazy

SaveH2O Justalittlebithippy akapacker
THANKS FOR THIS THREAD.
For what it's worth all the links with the pump and header tank are working as of tonight!
Think I'm about sorted!
Thanks again.

Sorry but I don't know what you are referring to.

Pump and.50L tank both still availiable All the info and links are still valid. Sale price on the 50L tank still $95.
https://www.bunnings.com.au/einhell-550 ... e_p4816143

http://nightingalecc.com.au/pressure-ta ... medium=cpc

Right!

The pressure tank is a good price, you can install more than one inline and they don't need to be close together but the additional tank's pressure must match the pump's tank's pressure.

The pressures must be checked and adjusted when the pressure tanks are empty. This usually means re-priming the pump but the pump's manual will state the requirement.

The pump would have a very easy life if fitted with the additional pressure tank and it is great value. Just make sure that the tank's outlet valve that supplies the pump isn't fitted very close to the bottom of the tank as so many (very foolishly) are.

The pump should also have a well ventilated cover and be kept out of direct sunlight.

Ooohhhh that will be a real rissk for the north west corner of the house! In South Australia.... Looks like i need to build it a cubbyhouse!!

You can have the pump anywhere provided the suction hose isn't too long, it doesn't have to be next to the tank.

Would the einhell pump discussed here be up to the rigours of supplying all water to a large highest house? We are solely on rainwater and the current pump sounds as though its on the brink.

Current setup is 2x22000l tanks to the current pump then via a uv filter setup into the house plumbing.

The Einhell is 550W and reasonably powerful but when you are totally reliant on rainwater for household use, you really don't want the Einhell because it has a pressure tank and the pump's controller operates with a cut in - cut out setting of about 21 - 41 psi. This will give you pressure fluctuations when having a shower. For total household use, you really need a cut in - cut out setting of at least 35-55 psi to reduce pressure fluctuations.

The best type of pump for total household use is a variable speed drive pump like a Grundfos. These will cost $$$ but they deliver the correct pressure on demand, are very energy efficient ($$$ savings), have a 'soft' start (no water hammer) and will have a long life.

When plumbing a pump, just make sure that the suction hose respects a straight section of at least 8 (internal) diameters before the pump. Fitting an elbow at the suction end will invariably reduce the pump's life but it is commonly done.

Thanks for the great advice. Yeah current pump is starting to vary the pressure pretty bad but think it could be issued related to our hot water system which we are waiting to have replaced.

There is several metres of straight pipe into the pump

The pressure variation I mentioned pertained to the Einhell pump having a low pressure setting pressure tank. While pressure tanks are great for reducing pump use and maximising the pump's operational efficiency, having the pump's cut in-cut out pressure settings at around 20-40 psi is far from ideal for showers.

A house will need a medium to moderately large pump to cater for the times when several fixtures are in use but most household pump use is supplying a single low flow demand fixture like a cistern (max 6 lpm) or an internal tap and shower etc. If you buy a large (non VSD) pump, it will operate at its maximum capacity despite there being low demand. This is inefficient energy use plus effectively nearly dead ending a pump reduces it's life span.

Also beware of buying a Davey pump with a Torrium pressure controller when you make your decision, the Torrium runs on for about 30 seconds after the demand stops. As an example, if you turn a tap on for 3 seconds to fill a glass, the pump will run for about 33 seconds. A whole of household pump can easily have 20,000 start-stops annually in an average household and some fixtures are multi demand for the one use as are washing machines and dishwashers.

Re the hot water system, if it has a sacrifical anode, just be aware that rainwater is naturally acidic and the anode used must be suitable for use. There are different anodes for different water qualities.

If you want to neutralise the tank's acidity, you can lower a nylon mesh bag full of limestone chips into the tank. Connect a small buoy to a tether because the chips will 'heal over' after 6 months or so and will need to be split again.

Thanks. Yeah the current pump has no pressure tank. Takes a little time now for pressure to kick in once turning a tap and the pressure when showering etc has recently become very inconsistent. More than 1fixture simultaneously is now out of the question

Have a look at the Grundfos Scala 2 VSD. It is a new pump that is great value for a VSD and ticks all the boxes.

http://www.grundfos.com/products/find-p ... cala2.html

Shop around for prices because they do vary. Also, if you register online, you get 4 years warranty.

http://www.aquiferpumps.com.au/grundfos-scala2/