SUPADIVERTA - syphonic rainwater diverter

WATER TANKS
HANDY HINTS

SELECTING THE RIGHT TANK

Before purchasing a tank, visit the web site of a reputable dealer who is an agent for several manufacturers and who lists the capacity and dimensions of each tank sold. You can then best select the most appropriate tank for your selected site. The rule with tanks is:
THE BIGGER, THE BETTER!!!

Syphonic fed inlets should be located a minimum 100mm above the bottom of the tank and the pump’s draw outlet fitted a minimum 80mm above the base OF ALL TANKS SOLD, regardless of the harvesting system used.
When not using SUPADIVERTA or a suitable pre tank filtering system, sediment buildup can be rapid and a pump connected to a low outlet WILL draw sludge/grit. In the past, huge numbers of pump draw valves have wrongly been fitted very close to the bottom of tanks!

ONLY A DEDICATED DRAIN/CLEANING OUTLET SHOULD EVER BE FITTED AT A LOW LEVEL

COUNCIL REGULATIONS

Avoid nasty surprises! Prior to purchase, check local regulations which may include possible height, colour and heritage restrictions, a requirement for a building permit to install a large tank or erect a tank stand, distance from fence lines and pump noise restrictions as well as tank construction material requirements in fire prone areas.

DO NOT BUY RUBBISH

Buy quality! A cheap tank can quickly turn into an expensive mistake. For expert advice, AQUATREK recommends a visit to www.watertanks.org.au This is the website for the Water Tank Group, a division of the Association of Rotational Moulders of Australia. A recommended download from this highly credible site is an independent report; “Solid advice about how to evaluate an imported tank”.

TANK LOCATION

Many homeowners select the tank location but forget about pipework that may form an archway between the downpipe and the tank. This has been particularly true with slimline tanks purchased to install `unobtrusively’ next to a fence. SUPADIVERTA allows previously installed ugly and obtrusive pipework or undesirable wet systems to be easily replaced at low cost and provides the option of increasing rainwater collection by legally harvesting additional downpipes. Full water tanks are heavy and should never be located immediately behind a retaining wall on the soil or material being retained! Full poly can also swell; NEVER site a tank against a house or other structures!

PLASTIC OR STEEL

Well built steel tanks will last much longer than plastic tanks and plastic tanks should never be used in fire prone areas. Tanks mounted on wooden stands are also not a good idea in such areas!

EVAPORATIVE AIR CONDITIONERS

Domestic units generally discharge between 6 and 12+ litres per hour but some newer models can be as low as 4 litres per hour. WELS ratings do not apply to these appliances at this time.
Householders are tempted to collect the discharge and use it to water their garden but due prudence is advised as THE DISCHARGE IS NECESSARY TO PURGE THE UNIT OF BUILT UP SALTS! While this discharge is a concern to many householders, the amount pales into insignificance when compared to the average 60 litres of water used per hour when operating the average domestic unit!

With the profusion of trendy dark rooves in the southern states, Aquatrek believes the use of heat reflective roof paint should be made mandatory in each state’s building code. The resultant lower roof cavity temperatures would cut air conditioner use AND save on energy bills.

PLASTIC TANKS ARE LIGHT

And water is heavy! If the tank is exposed to wind gusts, try not to drain the tank. Many tanks have lugs on their upper surface. These are tie down points and are often not explained to purchasers.

SLUDGE

Sludge removal is time consuming and unpleasant. SUPADIVERTA'S continuous sediment extraction diverts much of the finer heavier debris that passes through the 750 micron (0.75mm) filter, leaving minimal lighter material passing to the tank. A lot of this debris can also be removed before it reaches the tank by fitting a simple DIY sediment trap into the horizontal pipe work. Click LOW COST DIY FILTER

CLEANER WATER

If diverting to more than one tank, divert priority should be to the tank located away from the house. This is opposite to what is normally done!
If the water in that tank is then allowed to settle over the next few days and later decanted to replenish the tank next to the house, the house tank should remain virtually sludge free!

COVER UP

For longevity, try not to expose plastic tanks to strong sunlight. To restrict algal growth, choose dark colours and place weighted shade cloth over the inlet mesh. An accessory waiting to happen is an inexpensive tank cover made from shadecloth or similar UV stabilised material.

PUMPS

A pump’s start up energy demand is about four times its run demand and the frequent start ups and ‘cycling’ that promote excessive wear and tear is also a large component of total energy consumption. Many pumps are fitted with small pressure tanks that negate the pump’s need to start whenever a small amount of water is drawn but the ‘draw down’ is only about 50% of the tank’s capacity.
Aquatrek recommends the use of a large ‘stand alone’ pressure tank fed from the pump. A typical 100 litre tank can:

• Reduce pump start ups by 90% when connected to a toilet.
• Eliminate water hammer when connected to a washing machine.
• Reduce outdoor noise.
• Allow the use of a smaller and cheaper pump.
• Reduce energy costs.
• Allow the pump to operate at its optimum efficiency. Operating a pump at low efficiency can cause damage.

Large pressure tanks are also regularly available on eBay at reasonable prices. It is advisable to confirm the % drawdown prior to purchase.

CAVITATION can damage a pump. Cavitation occurs when low pressure bubbles form and nucleate against a surface, resulting in shock waves that can cause damage including impeller and casing corrosion. Cavitation typically emits a noisy rumbling sound which is often mistaken for worn bearings although it can be both.
Water passing through a 90 degree elbow fitted too close to a pump’s inlet can generate turbulence and low pressure that can cause cavitation.

A 90 DEGREE ELBOW SHOULD NOT BE FITTED TO A PUMP AT A DISTANCE THAT IS LESS THAN TEN TIMES THE INFEED PIPE’S DIAMETER.

Cavitation is an interesting but diversified subject that is well explained in the following link.
http://en.wikipedia.org/wiki/Cavitation

GRAVITY FED TOILET CISTERN

Do you need a pump if you connect a tank to a toilet?
ANSWER: Not always!
If you have a pump already connected to the toilet, does the pump always need to be turned on?
ANSWER: Not always.
A typical cistern has a water level approximately 750 mm above floor level and most rainwater tank heads are higher than this when full. The average person flushes a toilet six times a day which, for the average household, is nearly six thousand flushes a year. That is a lot of wear and tear on the pump!
Most cisterns have an inlet provision at each bottom end where a cistern float valve can be fitted. Most people are unaware of this but most are familiar with valves that have a long arm with a float at the end that sits in the water on the side opposite the valve.
The FLUIDMASTER cistern valve (400UK063) is compact, inexpensive (about $20) AND has the option of a very low pressure (red) gravity fed seal (242LP071). This optional seal allows a toilet to be gravity fed from a tank with a positive head.
VIEW HERE: http://www.haron.com.au/fluidmaster_products.html

FITTING:
Buy two Fluidmaster 400UK063 cistern valves and one 242LP071 low pressure seal.
Remove the plastic ‘pigs tail’ flow restrictor from the valve that will feed the rainwater.
Replace the standard seal in the above valve with the low pressure seal. Make sure you keep the arm lifted as per the instructions when turning the top cap.
To fit, simply remove the current valve (if it has a long float arm that would foul a second valve) and fit the two Fluidmaster valves.
Reconnect the standard pressure cistern valve to the mains water supply and connect the low pressure valve to a supply line fed from the tank.
Fit a stop cock to the rainwater supply line.
Fluidmaster cistern valves have an air gap at the top that prevents cross contamination. Nevertheless, do not have each valve open at the same time.
The fill rate (6 litres) will be about 4-5 minutes with a 1.5 metre head and about 7-8 minutes with a 1 metre head. At a .5 metre head, the flow slows to about 10-12 minutes. If the water passes through a (switched off) pump and empty pressure tank, the flow will be a little slower.

HINTS IF DIY: http://www.haron.com.au/fluidmaster_products.html
Auspex plastic pipe is easier to use than copper pipe and push on fittings are available.
http://www.auspex.com.au/PushFitSystem/

Do not attempt to drill through wall tiles unless you know how. Also check the wall cavity for water pipes etc before drilling all the way through.
If the float does not shut the flow off after the cistern fills, adjust the float lower into the water.
There are rebates available when connecting a tank to a toilet. Most of the work is fairly easy and you can save by buying and fitting the new valves and doing some other things yourself. If claiming a rebate, a plumber will have to connect the infeed pipe to the toilet and sign off the job as compliant. Many people do not have their tanks connected to a toilet because of high plumbing labour costs.

PLUMB THE HOT WATER SERVICE WITH RAINWATER

FACT: Most water tanks are under utilised.
Supplying rainwater to a toilet and/or a washing machine uses water all year and it is easy to also connect a dual water system to most hot water services, in fact, most hot water services are easier and cheaper to plumb with rainwater than a laundry or toilet. Unfortunately, rebates do not apply when supplying rainwater to a hot water service.

It is highly recommended that a suitable large capacity pressure tank is used to avoid constant pump start ups and to regulate a constant feed pressure. Have the hot water service’s minimum and maximum pressure rating checked for compatibility of use with the proposed system before purchasing equipment.

Filters must be fitted to avoid sediment transfer. Having the pump draw off valve at a suitable height above the bottom of the tank will be invaluable as will a good pre tank filtering system.

Electric hot water services installed in ‘hard water’ areas may be fitted with a sacrificial anode that is not suitable for use with rainwater. Always check the anode’s suitability for use and consider if the hot water service will alternate between mains and rainwater feed for extended periods.

AQUATREK strongly recommends that householders use a qualified plumber.

LOW PRESSURE

A pump delivering low pressure to a hose is a common frustration. Standard 12mm garden hoses have high friction losses and the longer the hose; the greater the loss. To reduce pressure loss, connect an 18mm hose to the tap, then join/connect to a shorter length of 12mm garden hose.
By comparison with 18mm garden hose at a flow rate of 20 litres per minute, a 12mm garden hose's friction loss is about eight times greater!

LEAKING FITTINGS

Google the internet for the yearly water loss from a tap leaking at one drip per second and you will find answers ranging from 1,000 to over 30,000 litres per year with most sites quoting either 7,000 or 12,000 litres per year! AQUATREK has conducted its own experiments and arrived at a figure of 4,800 litres per year. We also found that drip sizes can be varied (ours were generous) but not by the margin required to explain the wild variation in yearly estimates.
The above is easily calculated, simply count 600 drips (equal to 10 minutes) falling into a container, measure or weigh the volume, then use simple arithmetic to arrive at an annual total (1 litre = 1 kg).
Any loss should be avoided and most 12mm and 18mm hose connectors leak when fitted to 13mm and 19mm polypipe!