As the OP of this thread I thought I would post an update on how the system was performing after 12 mths.
The unique features of this wet system are the sediment trap and low infeeds (first flush) to a settling tank. See earlier diagrams posted previously. The low infeeds came as a result of a low head issue. Leaf diverters on the downpipes reduced the system's head to under the recommended minimum of 300mm. The low infeeds to tank 4 now provide plenty of head in the system. The head will vary from a maximum of around 2 metres and reduces as the tank 4 fills.
A big advantage of this setup is that after a long dry period tank 4 acts as a giant first flush. I can retain the 700+ litres sitting in the wet system pipes which is normally flushed out prior to rain. The sediment trap is an added bonus and collects most of the heavy sediments before they enter tank 4. The trap can be flushed out efficiently from time to time via the 40mm pipe at the end of the line. The reduction from 100mm to a length of 40mm pipe provides the required velocity (and suction) to expel sediment from the pipe.
The number one thing to report is I'm collecting very clean water which of course was the whole point of the exercise. Note: I do not use any water filters before or after the pump. So far the water is always fresh tasting with nil odour. The sediment trap and first flush to tank 4 seem to be removing any sediment from the wet system pipes thereby keeping the water fresher between rain events. Out of curiosity I have drained the wet system completely a couple of times and the water quality is excellent with nil odour.
Tanks 1 & 2 which supply the house so far have only a slightly visible sediment layer on the bottom. Tank 4 is a settling tank with a dedicated pump and is utilised for outside use on gardens etc. Tank 3 which is fed from the garage roof is also a settling tank and can top up the house tanks (or tank 4) via balance lines. The balance valves are 175mm off the tank's bottom so transfer quality decanted water.
I have certainly learned a thing or two about rainwater collection and storage over the past 18 months. I had zero knowledge to begin with and no past experience. I now clearly recognise that most plumbers have VERY limited knowledge on the subject and simply keep doing what they always have - repeatedly installing sub-standard systems on unsuspecting home owners. I would not be at all surprised if the subject of rain water harvesting is very much glossed over in a plumber's apprenticeship. And, most if not all councils desperately need to revisit their guidelines on rainwater collection and storage. They are completely inadequate. Approving first flush diverters off a wet system riser says it all.
I live in a rural area and a few of my neighbours often complain about their water quality. This is largely due to inadequate first flush methods and sediment build up in their wet system pipes with no way of effectively flushing/cleaning them out. One neighbour's system is completely closed and cannot be flushed or drained at all. Incredibly the same setup has no first flush devices. He also has the valves feeding the pump at the very bottom of the tanks close to the sediment layer. Another neighbour has first flush diverters off the tank risers and wasn't impressed when I explained why they were useless.
In the Gympie area we've had 3 major flood events since 2011 but have now been in drought since mid-2013. Still haven't had to truck in water and as long as it rains soon we should be right. One thing I've noticed during wind driven rain is that one tank can fill more than the other. Obviously one side of the pitched roof is collecting more water. Each side feeds to a separate tank. This is the reason SaveH2O refers to roof areas being subject to a multiplier when calculating compliant gutter and downpipe sizes.
Setting a wet system up correctly by following the advice available in this thread is not rocket science and will likely save you money in the long run. It does take a little research but this shouldn't be the case of course. You expect paid professionals to know their stuff but from what I can gather very few do. If I hadn't posted here I would've most likely ended up with the standard install my plumber had intended and now be complaining along with my neighbours.
Many thanks again to SaveH20 for your comprehensive knowledge and valuable contributions. You're a big asset to the forum.
John
P.S. A note on Camel tanks. I would not use them again. The tank walls slope out as they fill, a design feature they call it. It forces any valves fitted at the bottom of the tanks to point downwards which stresses the rigid buried connections going to the pump. I am working on a fix for this with a more flexible connection which is not as simple as it sounds. Camel tanks ignored my concerns and offered no solution. They have my money don't they. It has also affected the balance lines, see photo below. Note how the valves are distorting downwards and kinking the hose.
Various system photos:
Need advice on our rainwater collection and storage system.
Page 4 of 4
Good to hear progress stories. Your thread is going to be of great help to many people and you're right about SaveH20 - his advice has been of inestimable value to us all.
That's good to hear the progress!
It's good you've posted an update John with lots of photos and info.
Like anything, doing your homework beforehand gives you the tools to design and build exactly what you want ( and a big plug to SaveH2Os input too as others mention above ). Too often I've seen customers ripped off by tradies and/or designers/suppliers who really don't know what they are doing and they end up with an expensive problem.
Ha, that's Microsofts approach. " That's not a bug, that's a feature ! "
Stewie
Like anything, doing your homework beforehand gives you the tools to design and build exactly what you want ( and a big plug to SaveH2Os input too as others mention above ). Too often I've seen customers ripped off by tradies and/or designers/suppliers who really don't know what they are doing and they end up with an expensive problem.
Quote:
P.S. A note on Camel tanks. I would not use them again. The tank walls slope out as they fill, a design feature they call it. It forces any valves fitted at the bottom of the tanks to point downwards which stresses the rigid buried connections going to the pump. I am working on a fix for this with a more flexible connection which is not as simple as it sounds. Camel tanks ignored my concerns and offered no solution.
Ha, that's Microsofts approach. " That's not a bug, that's a feature ! "
Stewie
A summary can be invaluable and John is to be commended for posting the feedback.
This thread’s wet system was designed for John’s situation and location. Small modifications would be needed for other situations and areas. The following notes are for thread visitors interested in designing their own improved wet system.
The location (Gympie) has heavy seasonal rainfall in excess of John’s needs, the reason a dedicated flush/outdoors tank is used. The house supplies tanks 1 & 2 while the garage supplies tank 3. If filling priority to tanks 1 & 2 is needed, the 50 mm valves (diverted to tank 4) can be closed after the first +5 mm of rain.
Rural property owners should consider having separate tanks for indoor and outdoor use and direct the best quality harvested water to the dedicated house tank.
50 mm valves were chosen so that when the tanks are full and there is heavy rain during a 1:20 Average Recurrence Interval (ARI), the inflow to all 4 tanks will be equalised as much as possible to balance the overflow pipes. Using 40 mm inlets would not have allowed this. The valve size chosen will differ with different scenarios.
LOW RESTRICTION INLET
A smaller pipe branching off a vertical riser’s base and diverting to a low inlet provides a higher velocity low restriction flow path for any small bits of heavier debris. The normal flow velocity up a vertical riser is unable to do this, the reason why debris accumulates in standard wet system’s horizontal pipes.
Water flowing through a low restriction inlet oxygenates the tank's anaerobic zone and reduces the height of the water retained in the vertical riser and downpipes.
Low restriction inlets must be fitted a minimum of 100 mm above the bottom of a tank at the inlet’s lowest point and preferably within 75 degrees either side of an outlet that supplies a pump.
When a low restriction inlet is used, sealed mosquito proof leaf diverters must be fitted to the downpipes to prevent larger debris entering the tank. It is a regulatory requirement that water entering a tank must pass through mesh with apertures less than 1,000 microns (1 mm) in diameter.
A low restriction inlet operates with greater head pressure than water flowing up a vertical riser due to the height difference between the level of water in the tank and the height of the water in the vertical riser. This gives the low inlet priority flow which supplements the vertical riser's flow capacity, solving a common problem when fitting leaf diverters results in insufficient head.
LEAF DIVERTERS
Fitting leaf diverters to downpipes reduces the available head but a low restriction inlet increases the pipe’s flow rate, compensating for the lesser head. In John’s case, the 50 mm valves must be left open during heavy rain because the flow rate up the risers would be insufficient. This is particularly true during wind driven rain when one side of the house roof receives more rain than the other side. In this instance, only one valve may need to be left open.
The water retained in John’s wet system pipes when it stops raining is the cleanest water drained from the roof. Debris retained in standard wet system pipes depletes the water of oxygen as it breaks down, creating anaerobic (devoid of oxygen) conditions.
When mosquito proof leaf diverters are fitted to downpipes, only small particles flow into a wet system pipe. If a standard wet system is not fitted with leaf diverters and is only flushed a couple of times a year, the gradual debris build up can be significant. Water retained in a standard wet system pipe can be of worse quality than the first flush.
Because leaf diverters and sediment traps are used, the water in tank 4 is of better quality than the water in most water tanks fed by standard wet systems. When leaf diverters and a low inlet are used, the amount of tiny sediment particles entering the wet system is flushed every rain event, leaving only good quality water as confirmed by John.
Do not use leaf diverters that have a large aperture outer mesh and a finer inner mesh. These allow bird droppings and some organic matter to drop through the outer mesh and then wash through the finer inner mesh.
A leaf diverter also acts as an air gap to prevent the gutter back filling during a severe storm.
The best performing leaf diverter currently available is the ICON Leaf and Debris Controller.
FIRST FLUSH DIVERTERS
Never fit a first flush diverter to the top of wet system’s vertical riser! To do so only fills the diverter with the settled water retained in the riser while the first flush is still in the downpipe at the other end of the wet system! Incredibly, numerous wet systems are uselessly fitted with first flush diverters at the top of vertical risers, see photo below.
EDIT: First flush diverters fitted with drippers can waste 4-6 litres oof water per hour EACH! For households dependent on harvesting rainwater for potable use, this loss is unacceptable but manually drained first flush diverters allow the captured water to be used. The re-posted photos below show the first flush diverter fitted to John's garage dry system. The bottom cap is a Supadiverta 100mm first flush bottom cap.
EDIT:
When a sediment trap is also fitted to a non turbulent section of wet system pipe, a large percentage of the bed load is captured. Bed load is suspended sediment that has settled and gathered, initially into numerous small 'colonies'. Whereas suspended sediment travels with the water flow, bed load travels intermittently and much slower than the water. When it reaches an opening in the bottom of the pipe, it falls down and is later flushed. The sediment trap has been reposted below. Note that we now use an invert taper in lieu of the pipe reducer shown.
EDIT: 29/01/2019. Unfortunately, all photos and diagrams in this and other threads all 'disappeared' during a website upgrade a couple of years ago. If any reader has a query about anything in this or other threads, please feel free to contact me.
This thread’s wet system was designed for John’s situation and location. Small modifications would be needed for other situations and areas. The following notes are for thread visitors interested in designing their own improved wet system.
The location (Gympie) has heavy seasonal rainfall in excess of John’s needs, the reason a dedicated flush/outdoors tank is used. The house supplies tanks 1 & 2 while the garage supplies tank 3. If filling priority to tanks 1 & 2 is needed, the 50 mm valves (diverted to tank 4) can be closed after the first +5 mm of rain.
Rural property owners should consider having separate tanks for indoor and outdoor use and direct the best quality harvested water to the dedicated house tank.
50 mm valves were chosen so that when the tanks are full and there is heavy rain during a 1:20 Average Recurrence Interval (ARI), the inflow to all 4 tanks will be equalised as much as possible to balance the overflow pipes. Using 40 mm inlets would not have allowed this. The valve size chosen will differ with different scenarios.
LOW RESTRICTION INLET
A smaller pipe branching off a vertical riser’s base and diverting to a low inlet provides a higher velocity low restriction flow path for any small bits of heavier debris. The normal flow velocity up a vertical riser is unable to do this, the reason why debris accumulates in standard wet system’s horizontal pipes.
Water flowing through a low restriction inlet oxygenates the tank's anaerobic zone and reduces the height of the water retained in the vertical riser and downpipes.
Low restriction inlets must be fitted a minimum of 100 mm above the bottom of a tank at the inlet’s lowest point and preferably within 75 degrees either side of an outlet that supplies a pump.
When a low restriction inlet is used, sealed mosquito proof leaf diverters must be fitted to the downpipes to prevent larger debris entering the tank. It is a regulatory requirement that water entering a tank must pass through mesh with apertures less than 1,000 microns (1 mm) in diameter.
A low restriction inlet operates with greater head pressure than water flowing up a vertical riser due to the height difference between the level of water in the tank and the height of the water in the vertical riser. This gives the low inlet priority flow which supplements the vertical riser's flow capacity, solving a common problem when fitting leaf diverters results in insufficient head.
LEAF DIVERTERS
Fitting leaf diverters to downpipes reduces the available head but a low restriction inlet increases the pipe’s flow rate, compensating for the lesser head. In John’s case, the 50 mm valves must be left open during heavy rain because the flow rate up the risers would be insufficient. This is particularly true during wind driven rain when one side of the house roof receives more rain than the other side. In this instance, only one valve may need to be left open.
The water retained in John’s wet system pipes when it stops raining is the cleanest water drained from the roof. Debris retained in standard wet system pipes depletes the water of oxygen as it breaks down, creating anaerobic (devoid of oxygen) conditions.
When mosquito proof leaf diverters are fitted to downpipes, only small particles flow into a wet system pipe. If a standard wet system is not fitted with leaf diverters and is only flushed a couple of times a year, the gradual debris build up can be significant. Water retained in a standard wet system pipe can be of worse quality than the first flush.
Because leaf diverters and sediment traps are used, the water in tank 4 is of better quality than the water in most water tanks fed by standard wet systems. When leaf diverters and a low inlet are used, the amount of tiny sediment particles entering the wet system is flushed every rain event, leaving only good quality water as confirmed by John.
Do not use leaf diverters that have a large aperture outer mesh and a finer inner mesh. These allow bird droppings and some organic matter to drop through the outer mesh and then wash through the finer inner mesh.
A leaf diverter also acts as an air gap to prevent the gutter back filling during a severe storm.
The best performing leaf diverter currently available is the ICON Leaf and Debris Controller.
FIRST FLUSH DIVERTERS
Never fit a first flush diverter to the top of wet system’s vertical riser! To do so only fills the diverter with the settled water retained in the riser while the first flush is still in the downpipe at the other end of the wet system! Incredibly, numerous wet systems are uselessly fitted with first flush diverters at the top of vertical risers, see photo below.
EDIT: First flush diverters fitted with drippers can waste 4-6 litres oof water per hour EACH! For households dependent on harvesting rainwater for potable use, this loss is unacceptable but manually drained first flush diverters allow the captured water to be used. The re-posted photos below show the first flush diverter fitted to John's garage dry system. The bottom cap is a Supadiverta 100mm first flush bottom cap.
EDIT:
When a sediment trap is also fitted to a non turbulent section of wet system pipe, a large percentage of the bed load is captured. Bed load is suspended sediment that has settled and gathered, initially into numerous small 'colonies'. Whereas suspended sediment travels with the water flow, bed load travels intermittently and much slower than the water. When it reaches an opening in the bottom of the pipe, it falls down and is later flushed. The sediment trap has been reposted below. Note that we now use an invert taper in lieu of the pipe reducer shown.
EDIT: 29/01/2019. Unfortunately, all photos and diagrams in this and other threads all 'disappeared' during a website upgrade a couple of years ago. If any reader has a query about anything in this or other threads, please feel free to contact me.
A summary can be invaluable and John is to be commended for posting the feedback.
This thread’s wet system was designed for John’s situation and location. Small modifications would be needed for other situations and areas. The following notes are for thread visitors interested in designing their own improved wet system.
A smaller pipe branching off a vertical riser’s base and diverting to a low inlet provides a high velocity low restriction flow path for sediment. Flow velocity up a vertical riser is unable to do this, the reason why debris accumulates in standard wet system’s horizontal pipes.
The location (Gympie) has heavy seasonal rainfall in excess of John’s needs, the reason a dedicated flush/outdoors tank is used. The house supplies tanks 1 &2 while the garage supplies tank 3. If filling priority to tanks 1 & 2 is needed, the 50 mm valves (diverted to tank 4) can be closed after the first +5 mm of rain.
Rural property owners should consider having separate tanks for indoor and outdoor use and direct the best quality harvested water to the dedicated house tank.
50 mm valves were chosen so that when the tanks are full and there is heavy rain during a 1:20 Average Recurrence Interval (ARI), the inflow to all 4 tanks will be equalised as much as possible to balance the overflow pipes. Using 40 mm inlets would not have allowed this. The valve size chosen will differ with different scenarios.
A low restriction inlet must be fitted a minimum of 100 mm above the bottom of the tank at the inlet’s lowest point and preferably within 75 degrees of an outlet that supplies a pump.
When a low restriction inlet is used, sealed mosquito proof leaf diverters must be fitted to the downpipes to prevent larger debris entering the tank. It is a regulatory requirement that water entering a tank must pass through mesh with apertures less than 1,000 microns (1 mm) in diameter.
A low restriction inlet operates with greater head pressure than water flowing up a vertical riser due to the height difference between the level of water in the tank and the height of the vertical riser. This gives the low inlet priority flow and increases the flow rate through the wet system, solving a common problem when fitting leaf diverters results in insufficient head.
Because leaf diverters and sediment traps are used, the water in tank 4 is still of better quality than the water in most water tanks fed by standard wet systems. When leaf diverters and a low inlet are used, the small amount of sediment entering the wet system is flushed every rain event, eliminating the gradual build up of debris in wet system pipes.
Do not use leaf diverters that have a coarse outer mesh and a finer inner mesh. These allow bird droppings and other smaller organic matter to drop through the outer mesh and then wash through the finer inner mesh. This design is known as an entrapment filter. Only use a leaf diverter that has a fine outer mesh (diversion filter).
A leaf diverter also acts as an air gap to prevent the gutter back filling during a severe storm.
Never fit first flush diverters to the top of wet system’s vertical risers! To do so only fills the diverter with the water retained in the riser while the first flush is still in the downpipe at the other end. Incredibly, numerous wet systems are fitted with first flush diverters at the top of vertical risers.
Fitting leaf diverters to downpipes reduces the available head but a low restriction inlet increases the pipe’s flow rate, compensating for the lesser head. In John’s case, the 50 mm valves must be left open during heavy rain because the flow rate up the risers would be insufficient. This is particularly true during wind driven rain when one side of the house roof receives more rain than the other side. In this instance, only one valve may need to be left open.
The water retained in John’s wet system pipes when it stops raining is the cleanest water drained from the roof. Debris retained in standard wet system pipes depletes the water of oxygen when it breaks down, creating anaerobic (devoid of oxygen) conditions because the water in the pipe cannot breathe, unlike water in a tank.
When leaf diverters are fitted to downpipes, not a lot of debris flows into a wet system pipe every rainfall but if a standard wet system is only flushed a couple of times a year, the gradual debris build up can be significant. Water retained in a standard wet system pipe can be of worse quality than the first flush.
This thread’s wet system was designed for John’s situation and location. Small modifications would be needed for other situations and areas. The following notes are for thread visitors interested in designing their own improved wet system.
A smaller pipe branching off a vertical riser’s base and diverting to a low inlet provides a high velocity low restriction flow path for sediment. Flow velocity up a vertical riser is unable to do this, the reason why debris accumulates in standard wet system’s horizontal pipes.
The location (Gympie) has heavy seasonal rainfall in excess of John’s needs, the reason a dedicated flush/outdoors tank is used. The house supplies tanks 1 &2 while the garage supplies tank 3. If filling priority to tanks 1 & 2 is needed, the 50 mm valves (diverted to tank 4) can be closed after the first +5 mm of rain.
Rural property owners should consider having separate tanks for indoor and outdoor use and direct the best quality harvested water to the dedicated house tank.
50 mm valves were chosen so that when the tanks are full and there is heavy rain during a 1:20 Average Recurrence Interval (ARI), the inflow to all 4 tanks will be equalised as much as possible to balance the overflow pipes. Using 40 mm inlets would not have allowed this. The valve size chosen will differ with different scenarios.
A low restriction inlet must be fitted a minimum of 100 mm above the bottom of the tank at the inlet’s lowest point and preferably within 75 degrees of an outlet that supplies a pump.
When a low restriction inlet is used, sealed mosquito proof leaf diverters must be fitted to the downpipes to prevent larger debris entering the tank. It is a regulatory requirement that water entering a tank must pass through mesh with apertures less than 1,000 microns (1 mm) in diameter.
A low restriction inlet operates with greater head pressure than water flowing up a vertical riser due to the height difference between the level of water in the tank and the height of the vertical riser. This gives the low inlet priority flow and increases the flow rate through the wet system, solving a common problem when fitting leaf diverters results in insufficient head.
Because leaf diverters and sediment traps are used, the water in tank 4 is still of better quality than the water in most water tanks fed by standard wet systems. When leaf diverters and a low inlet are used, the small amount of sediment entering the wet system is flushed every rain event, eliminating the gradual build up of debris in wet system pipes.
Do not use leaf diverters that have a coarse outer mesh and a finer inner mesh. These allow bird droppings and other smaller organic matter to drop through the outer mesh and then wash through the finer inner mesh. This design is known as an entrapment filter. Only use a leaf diverter that has a fine outer mesh (diversion filter).
A leaf diverter also acts as an air gap to prevent the gutter back filling during a severe storm.
Never fit first flush diverters to the top of wet system’s vertical risers! To do so only fills the diverter with the water retained in the riser while the first flush is still in the downpipe at the other end. Incredibly, numerous wet systems are fitted with first flush diverters at the top of vertical risers.
Fitting leaf diverters to downpipes reduces the available head but a low restriction inlet increases the pipe’s flow rate, compensating for the lesser head. In John’s case, the 50 mm valves must be left open during heavy rain because the flow rate up the risers would be insufficient. This is particularly true during wind driven rain when one side of the house roof receives more rain than the other side. In this instance, only one valve may need to be left open.
The water retained in John’s wet system pipes when it stops raining is the cleanest water drained from the roof. Debris retained in standard wet system pipes depletes the water of oxygen when it breaks down, creating anaerobic (devoid of oxygen) conditions because the water in the pipe cannot breathe, unlike water in a tank.
When leaf diverters are fitted to downpipes, not a lot of debris flows into a wet system pipe every rainfall but if a standard wet system is only flushed a couple of times a year, the gradual debris build up can be significant. Water retained in a standard wet system pipe can be of worse quality than the first flush.
Thank you for all the information.
We will be going from dam water to tank and town water (old bore there too but above ground pump in 20yrs)
So very appreciate of all the tips. Do you do consults on individual situations through your business?
No. Sorry. I have done so in the past but it just impacts too much on my time.
I research and develop new products. I just give advice on the forum about rainwater harvesting because I have a passion for environmental management and water conservation plus I have retained the rights to a couple of rainwater harvesting products that I have developed. I also want to publicise this harvesting method whenever I can because of the number of calls I get from people with stagnant water tanks.
If you are off the water grid, then you undoubtedly will have a wet system. The low inlet and sediment trap are very easy to plumb and they improve the water quality and increase yield. It really is an easy method to have. The flow calculations must be correctly worked though.
In many instances, people can just have a large low inlet valve and do away with the vertical riser all together. The water flowing into the tank also oxygenates the anaerobic zone whereas water falling from a vertical riser into the tank can cause significant sediment re-suspension during heavy rain.
Just start a new thread in the Eco Living sub forum, that way others will also benefit.
A lot of people have already benefited from John's thread. Unfortunately, many people ask for advice and then remove photos and diagrams once they have what they want but John has posted additional photos and feedback for the benefit of others. It hasn't gone unnoticed.
EDIT: Unfortunately, photos and diagrams disappeared from (probably?) all older forum threads including this one a few years ago, one of the dangers of using sites like the old Photo Bucket.
I research and develop new products. I just give advice on the forum about rainwater harvesting because I have a passion for environmental management and water conservation plus I have retained the rights to a couple of rainwater harvesting products that I have developed. I also want to publicise this harvesting method whenever I can because of the number of calls I get from people with stagnant water tanks.
If you are off the water grid, then you undoubtedly will have a wet system. The low inlet and sediment trap are very easy to plumb and they improve the water quality and increase yield. It really is an easy method to have. The flow calculations must be correctly worked though.
In many instances, people can just have a large low inlet valve and do away with the vertical riser all together. The water flowing into the tank also oxygenates the anaerobic zone whereas water falling from a vertical riser into the tank can cause significant sediment re-suspension during heavy rain.
Just start a new thread in the Eco Living sub forum, that way others will also benefit.
A lot of people have already benefited from John's thread. Unfortunately, many people ask for advice and then remove photos and diagrams once they have what they want but John has posted additional photos and feedback for the benefit of others. It hasn't gone unnoticed.
EDIT: Unfortunately, photos and diagrams disappeared from (probably?) all older forum threads including this one a few years ago, one of the dangers of using sites like the old Photo Bucket.
Bookmarking thanks h20 and John
So much great information here. I read with interest about putting a header tank in the roof space to feed the toilet cisterns to save the pump and I was wondering how to size it?
Hi cjh,
This is John's thread but I don't think that he will mind if I answer.
Cisterns are high use low flow devices and if you can save on pump wear and tear, you are on a winner.
The advantage of using a header tank over a pressure tank is that nearly the total volume of a header tank can be used before a float activates the pump whereas a pressure tank has about 35% draw down because of the bladder plus a header tank is usually cheaper.
There are many float valves to choose from. You would also be wise to fit an overflow pipe. You also need to have the header tank fitted with mosquito proof mesh.
If you are also considering supplying rainwater to a washing machine, just be aware that many modern washing machines have high pressure solenoids and for those that don't, the flow will still be slow from a header tank.
You can have the header tank any size you like, it just depends on the space you have. Just remember that 1 litre = 1 kg.
A tank with a 20 litre draw down would save about 80% of pump start/stops when supplying a cistern. For most households, this would save several thousand pump start ups every year.
You will need to supply the harvested water to a second cistern valve. The Fluidmaster 400UK063 and the low pressure valve seal 242LP071 is discussed earlier in the thread. The doc below shows the optional twin cistern valve plumbing.
http://www.vba.vic.gov.au/__data/assets ... sterns.pdf
http://haron.com.au/fluidmaster_products.html
This is John's thread but I don't think that he will mind if I answer.
Cisterns are high use low flow devices and if you can save on pump wear and tear, you are on a winner.
The advantage of using a header tank over a pressure tank is that nearly the total volume of a header tank can be used before a float activates the pump whereas a pressure tank has about 35% draw down because of the bladder plus a header tank is usually cheaper.
There are many float valves to choose from. You would also be wise to fit an overflow pipe. You also need to have the header tank fitted with mosquito proof mesh.
If you are also considering supplying rainwater to a washing machine, just be aware that many modern washing machines have high pressure solenoids and for those that don't, the flow will still be slow from a header tank.
You can have the header tank any size you like, it just depends on the space you have. Just remember that 1 litre = 1 kg.
A tank with a 20 litre draw down would save about 80% of pump start/stops when supplying a cistern. For most households, this would save several thousand pump start ups every year.
You will need to supply the harvested water to a second cistern valve. The Fluidmaster 400UK063 and the low pressure valve seal 242LP071 is discussed earlier in the thread. The doc below shows the optional twin cistern valve plumbing.
http://www.vba.vic.gov.au/__data/assets ... sterns.pdf
http://haron.com.au/fluidmaster_products.html
Thanks for the info, didn't mean to hijack someone's thread. I think I might need to start a new thread as I see a number of questions in my future.
This might be a silly question, but is it better to have the inlet directly over the outlets or as far away as possible? Surely, there would be more turbulence below the inlets, and it'd stir up all the muck just below the outlet?
I guess the good thing, would be maybe that would mean less would settle around the outlet? Or does it really matter???
I guess the good thing, would be maybe that would mean less would settle around the outlet? Or does it really matter???
I assume that you are referring to the tank's top meshed inlet and the tank's outlet valve that supplies the pump.
Most tanks have the outlet valve fitted very low at the bottom and having the top meshed inlet above the outlet valve is not a good idea as falling water will cause sediment resuspension.
The tank's meshed overflow outlet also needs to be accessible from the tank's top inlet as the overflow mesh can gum up and this also needs consideration when deciding on the best location for the top inlet, the overflow outlet and the bottom outlet valve that supplies the pump.
Designing the system so that the pump is supplied by a floating intake like a WaterBoy and a supplementary low restriction inlet adds very little to the overall cost and also having a settling tank system combined with sediment traps and a TankVac overflow system will give you delivered water quality that will be in the top % of installations.
Of interest, if you pour water into a glass container, you will see that the bubbles don't go down very far at all and this leads people to believe that a tank doesn't need a lot of water depth to 'cushion' the effects that falling water may have on the sediment layer. What isn't seen are the generated toroidal vortices that cause sediment resuspension when they impact on the bottom boundary layer.
Toroidal (ring) vortices travel slowly but they rotate very fast to hold their shape for a long time due to rotation stabilising other motion. It is the fast rotating ring and not the vortex velocity that impacts on the sediment layer.
I have linked a discussion paper below that has some photos of impacting toroidal vortices that you might find interesting. I have also linked a You Tube video that shows underwater toroidal vortices that you should enjoy watching. The first 30 seconds is a bit slow though!
http://www.damtp.cam.ac.uk/lab/people/s ... alziel.pdf
https://www.youtube.com/watch?v=mHyTOcfF99o
Most tanks have the outlet valve fitted very low at the bottom and having the top meshed inlet above the outlet valve is not a good idea as falling water will cause sediment resuspension.
The tank's meshed overflow outlet also needs to be accessible from the tank's top inlet as the overflow mesh can gum up and this also needs consideration when deciding on the best location for the top inlet, the overflow outlet and the bottom outlet valve that supplies the pump.
Designing the system so that the pump is supplied by a floating intake like a WaterBoy and a supplementary low restriction inlet adds very little to the overall cost and also having a settling tank system combined with sediment traps and a TankVac overflow system will give you delivered water quality that will be in the top % of installations.
Of interest, if you pour water into a glass container, you will see that the bubbles don't go down very far at all and this leads people to believe that a tank doesn't need a lot of water depth to 'cushion' the effects that falling water may have on the sediment layer. What isn't seen are the generated toroidal vortices that cause sediment resuspension when they impact on the bottom boundary layer.
Toroidal (ring) vortices travel slowly but they rotate very fast to hold their shape for a long time due to rotation stabilising other motion. It is the fast rotating ring and not the vortex velocity that impacts on the sediment layer.
I have linked a discussion paper below that has some photos of impacting toroidal vortices that you might find interesting. I have also linked a You Tube video that shows underwater toroidal vortices that you should enjoy watching. The first 30 seconds is a bit slow though!
http://www.damtp.cam.ac.uk/lab/people/s ... alziel.pdf
https://www.youtube.com/watch?v=mHyTOcfF99o
In many instances, people can just have a large low inlet valve and do away with the vertical riser all together. The water flowing into the tank also oxygenates the anaerobic zone whereas water falling from a vertical riser into the tank can cause significant sediment re-suspension during heavy rain.
Does a low inlet valve mean that water would enter the tank via a valve toward the bottom of the tank, instead of via a vertical riser that feeds to the top of the tank?
So the large low inlet valve would just need to have a filter on it?
Why would anyone choose a vertical riser over a large low inlet valve?
Would having a large low inlet valve increase the head and therefore water pressure?
Thanks.
In many instances, people can just have a large low inlet valve and do away with the vertical riser all together. The water flowing into the tank also oxygenates the anaerobic zone whereas water falling from a vertical riser into the tank can cause significant sediment re-suspension during heavy rain.
Does a low inlet valve mean that water would enter the tank via a valve toward the bottom of the tank, instead of via a vertical riser that feeds to the top of the tank?
Yes. This modification to standard wet systems replicates the Supadiverta rainwater harvesting system.
So the large low inlet valve would just need to have a filter on it?
Yes, the filter would be a good mosquito proof leaf diverter fitted to the downpipe. Fitting an additional simple wet system sediment trap that uses off the shelf fittings to capture and flush bed load also has benefit and was also learned during our initial rainwater harvesting research and development program before the Supadiverta was even thought of.
Why would anyone choose a vertical riser over a large low inlet valve?
Most plumbers and installers have minimal knowledge about rainwater harvesting best practice and simply copy what everyone else does, the reason why nearly all rainwater harvesting systems are poorly designed and sub standard.
If the downpipes are diverted to a low inlet, the hydraulic inflow calculations must ensure that the system will still flow with enough capacity and a safety margin to drain the roof when the tank is full during a 1:20 Average Recurrence Interval rain event.
Because vertical risers discharge into a tank from above the tank's roof, the low inlet will always operate with more minimum head than a vertical riser's constant head when the tank is full because the tank's water level is obviously always lower than the top of the vertical riser plus the flow path has less friction loss but large inlet valves are expensive and very, very few plumbers or installers know how to calculate flow rates through a smaller inlet. This of course is when all other things are equal, for example, both scenarios are fitted with mosquito proof leaf diverters at the downpipes that unfortunately result in head loss.
Water entering a storage tank must first pass through mosquito proof filter mesh. Standard wet systems are often plumbed without leaf diverters which instantly makes the system sub standard but a low inlet must be fitted with a leaf diverter at the downpipe because there is no other filter before the water enters the tank. This is why all systems need to have the tank's inflow calculations done along with the tank's overflow capacity to ensure it exceeds the inflow rate during heavy rain when the tank is full.
CAUTION: Rant ahead!
The fact is that installers have always diverted water to the top of tanks and drawn it from the bottom whereas the best way is to do the opposite but that is not all!
Questions never asked!
Why are there some poly tanks that have a very low molded threaded outlet socket that is only suitable as a drain valve yet there is no higher threaded socket molded that is suitable for connecting to the pump? This forces people to connect the pump to a drain valve and draw water from the anaerobic zone? Some tanks are fitted with a drain valve and an outlet to fill a watering can but no pump outlet.
Why are tanks optioned so that water flows into the tank through a meshed inlet that is fitted above the outlet that the pump draws water from?
Why are many tanks optioned without an access hatch that allows the overflow mesh to be cleaned?
Why are customers not told the tank's overflow capacity and why don't the tank manufacturers even know?
Why do you even need an overflow pipe, why not eliminate the overflow pipe and only fill the tank to a predetermined height that will also increase the tank's capacity?
Why do many of the slimline poly tanks supplied to unsuspecting customers still have designs that make desludging the bottom near impossible?
Why are first flush diverters fitted at the top of vertical risers when the first flush will still be in the downpipe at the end of the wet system when if first rains?
Why do installers invariably install submersible pumps directly on the tank's floor when many pumps suction water in from near the bottom of the pump even though it is often against the terms and conditions of warranty?
Why do installers fit overflow pipes without expansion joints when the tank sits on reactive ground?
Why do installers fit a pump's suction hose to a 90 degree elbow fitted directly to the pump?
Why do installers fit the pump to the tank that the water is diverted to when there is more than one tank that would otherwise allow having a superior settling system?
Why do installers fit powerful pumps with small supply pipes when they are only supplying slow fill short duration end fixtures like toilet cisterns and washing machines.
viewtopic.php?f=35&t=61588&p=956938&hilit=bucket#p956938
Would having a large low inlet valve increase the head and therefore water pressure?
Yes. The head will also vary with the tank's changing water level but a leaf diverter has to be fitted. NOTE: This isn't a regulatory requirement in many areas
Having an additional low restriction inlet valve also supplements a wet system's flow rate if still used in conjunction with a vertical riser but if you can do away with the vertical riser altogether, then it saves on material and labour costs plus it is neater. It also confuses everyone! Note that the tanks below are fed by our Supadiverta system, it is the same flow path except that the downpipes remain intact as does the storm water system. The tanks are not fitted with overflow pipes because the Supadivertas will only divert water to a pre determined level in the tank. This also gives additional storage capacity.
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