Browse Forums Landscape & Garden Design Re: Tank / rainwater system missing filter 2Mar 13, 2013 4:48 pm The Harder You Try - the Luckier You Get ! Web site http://www.anewhouse.com.au Informative, Amusing, and Opinionated Blog - Over 600 posts on all aspects of building a new house. Re: Tank / rainwater system missing filter 3Mar 13, 2013 7:55 pm 3in1 Supadiverta. Rainwater Harvesting Best Practice using syphonic drainage. Cleaner Neater Smarter Cheaper Supa Gutter Pumper. A low cost syphonic eaves gutter overflow solution. Re: Tank / rainwater system missing filter 4Mar 14, 2013 9:54 am Thanks so much to you both for the help. The tank does have a first flush diverter and the "water collecting funnel" (excuse the technical language) that the downpipe goes into has a mesh screen over it to stop leaves. I'm not sure where the outlet supplying the tank is fitted, unfortunately. If it's not clear in the photos below I can try and find out. I wondered about sediment building up in the bottom of the tank, so I flushed out a few litres from the outlet valve on the bottom and the water looked perfectly clear to me. Of course I'm not sure whether this is an indication that it's actually all clear in there though. There are some photos below. It's a 5000 litre tank. I'm not sure about the dimensions but I can measure it up tonight. I'm not exactly sure but I think the builder said that three of the downpipes were diverted to it. I'm not sure exactly what you mean by the 'flow path to the tank' though. Hopefully it might be clear by the photos below? Also, re spending some more to fix the problem and gaining additional storage space and/or modifying with a higher outlet - with time and budget commitments we're primarily concerned with just fixing the sediment problem at this stage. If these are nesessary to fix the problem then I suppose we'll need to look at them, but I was also wondering whether installing the filter would be a good start too? Really appreciate the help. Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Re: Tank / rainwater system missing filter 5Mar 14, 2013 2:00 pm The photos are a great help but the news is not good. I will firstly describe what you have so that you understand the system and the problems and then give some thoughts on possible solutions. Unfortunately, most tank installs are sub standard as plumbers have no training and very few have a clue or even care. I assume that you are either in QLD or northern NSW. PUMP You will notice that there is a power lead going into the tank and a smaller pipe coming out of the tank near the tank's top meshed inlet. This is the power supply for and the water pipe from a submersible pump. The small pipe feeds water to the Rainbank. It is really bad to have the pump directly below the downpipes that feed into a tank through a top meshed inlet as the inflow will cause sediment resuspension that results in dirty water being drawn into the pump. Water falling even a short distance generates toroidal vortices. These are ring shaped and they rotate inwards at high velocity. Toroidal vortices travel slowly but microburst with a force far greater than their descent velocity. Rotation is necessary to maintain the ring as rotation stabilises other motion. For the reasons just mentioned, the tank does not have to be near empty to have the sediment layer directly under the falling water stirred up. If the sediment layer is fairly thick, then the pump could also be sucking muck directly from the sediment layer. INFORMATION ON MICROBURSTS & IMPACTING VORTICES http://en.wikipedia.org/wiki/Microburst http://www.damtp.cam.ac.uk/lab/people/s ... alziel.pdf TOROIDAL VORTICES - bear with the slow opening. http://www.youtube.com/watch?v=EISHbRxgi-8 HAVING FUN WITH TOROIDAL VORTICES http://www.youtube.com/watch?feature=fv ... kACZy2ZD2k RAINBANK The Rainbank is an automatic mains water switching device that changes to mains water when the tank level gets low. The pump supplies the Rainbank. The operational mode is proof that the tank's water level does not need to be low for the submersible pump to draw dirty water. If a water tank pump supplies sanitary flushing, an automatic or manual mains water switching device is required. The problem is that plumbers either don't know the regulations or they just want the extra income by supplying and fitting an expensive automatic device rather than something much simpler and cheaper like a RainAid that costs $130-140. Very few new home buyers are told of their options and cases of new home owners being supplied with unnecessarily large pumps and expensive automatic mains water switching devices is rife. http://www.apexvalves.co.nz/plumbing/apex/rainaid.html Having a Rainbank also restricts the rectification options available as does the submersible pump. You will notice however that the horizontal pipe coming out of the Rainbank has a Y fitting. There is also another Y fitting on the small water pipe fitted between the tank and the Rainbank. If you turn off the pump etc and undo the Y fittings, you should find that they are filters of sorts. Just open one up and have a look see. The problem with inline filters is that for them to work, they must capture and retain debris and so they are generally coarse apertured so they don't block but a Y fitting gives some protection against this. I am also 99% sure that it is not compliant for the pipe that connects the pump to the Rainbank to not have a flexible fitting and I can check this if necessary. FIRST FLUSH DIVERTER The one that I see in the photos is an absolute joke. REASON: It is fitted near the top of a wet system vertical riser. Just to explain. The infeed pipe appears to be a 90mm PVC stormwater pipe. These are measured as an outside diameter; the most common ones have an internal diameter of 86.2mm. This gives them an internal volume of about 5.8 litres per metre. The accepted minimum required flushing velocity of HORIZONTAL drain pipe is .6 metres per second or (5.8 x .6) 3.5 litres per second for a flooded 86mm ID PVC stormwater pipe. This is 210 litres per minute but remember...the vertical riser is VERTICAL! If the pipe was serviced by let's say 35 sq m of roof, this equates to 35 litres per minute for every 1 mm of rain per minute and so you would need 6mm of rain per minute to deliver the required flush rate of 210 litres per minute to a flooded horizontal pipe. All that will happen is that the water that has remained in the vertical riser (that has settled) is the water that will fill the 'first flush diverter' while the actual first flush will be still down the other end of the pipe! The first flush diverter is useless. I will just mention here that the required flushing water volume is different for wet system pipes as normal drain pipes are obviously not flooded and flow at greater velocity with less water. WET SYSTEM INSPECTION OPENING You will notice that there is a capped opening on a short horizontal section of pipe near the bottom of the vertical riser. These are required in many areas so that the underground wet system pipe can be flushed of debris to prevent the retained water from stagnating. Just to explain, when organic matter breaks down, it takes oxygen from the water and the water becomes anaerobic. The next step is stagnation. The IO that you have is next to useless as the driving head when opened will only be from the top of the first flush diverter. For the wet system pipe to flush, it needs a good driving head fron the downpipe but even if there was no first flush diverter fitted to the vertical riser, the driving head would only be the level at the top of the riser. The IO is also very obviously fitted well above the level of the underground wet system pipe. IO's are best fitted at the same level as the buried pipe but unless the pipe can be run down a slope, this option is not always available. RAIN HEADS / LEAF DIVERTERS These are required in many areas, particularly in northern NSW & QLD, to: (a) Prevent leaves and other organic matter from entering the wet pipes. (b) Prevent mosquitoes from breeding. Most areas also require a flap valve to be fitted to a wet system pipe where it discharges to a tank's top meshed inlet. Your wet system pipe does not have one fitted. WHAT CAN BE DONE? I could recommend many things but the following is a 'budget' starter. You should firstly desludge the tank and this will give an immediate fix. Check the Y fittings as they are probably filters. Have a look at the underground wet system pipe and see if there is anywhere along its run where a tee could be fitted, preferably close to the tank. This could then be attached to a branch pipe and run to a convenient area and used to flush the wet system. Alternatively (and better), you could plumb in a simple sediment trap like the one discussed in the thread linked below. Just modify it to the 90mm wet pipe and your own situation. viewtopic.php?f=35&t=60317 If you could find or have made a sealed cylinder that was fitted to the pipe between the tank and the Rainbank and used this as a small settling tank (maybe 20 litres), the water from the pump could enter about 1/4 of the way up and the water would exit at the top. Also have a drain outlet on the bottom (the 'tank' may need a stand). You could make room for it by removing the useless first flush diverter from the vertical riser. Also look at buying some aquarium filter and cut it to size to fit over the tank's top meshed inlet. This will capture sediment but it will need regular cleaning. EDIT: The 3-4 hundred dollars I first referred to was to purchase a smaller same height tank and fit the pump to that tank. That would have allowed the original tank to retain the same infeed pipes but to also serve as a settling tank and supply the smaller tank with decanted water. The submersible pump and the rainbank would make doing this a costly exercise if a plumber was involved. The best rainwater harvesting systems use settling tank systems. 3in1 Supadiverta. Rainwater Harvesting Best Practice using syphonic drainage. Cleaner Neater Smarter Cheaper Supa Gutter Pumper. A low cost syphonic eaves gutter overflow solution. Re: Tank / rainwater system missing filter 6Mar 15, 2013 2:12 pm Wow, thanks for such a comprehensive and helpful reply SaveH20. To be honest I'm still absorbing a lot of it as there seems to be a lot there for me to pick up. I’ll get some acquarium filter and fit that to the top meshed inlet - any particular courseness or grade that would be best to use? I’ll check if there are filters in the Y fittings and clean them out if so. I'm also still wondering specifically about the cartridge filter, which they quoted as $160 to supply and install. Would this be worthwhile getting to remove some of the sediment, or due to our poor setup would the filter not be effective? With the install so far I'm inclined to avoid having the same company install the filter and would prefer to have somebody else install it, or even do it ourselves if it's easy enough. Desludging – is this something we can do ourselves by letting water out of the outlet valve on the bottom, or is it something we'd be better off getting a professional in for? I've read that they pump the sludge out of the bottom which presumably does a more thorough job. There’s another opening in the top of the tank (at the other end) with no pipes sticking into it, which looks similar to the one in the photos but this one doesn't have any pipes going into it (I can take a photo if it helps). Could we get a plumber or tank installer / maintainer out to shift the pump inside so that it’s operating at the other end of the tank, with the outgoing pipe coming out of this other hole in the top, and therefore away from the downpipes? If so, would this be a worthwhile change or would the main problem lie elsewhere? I must admit you've lost me a little with the first flush diverter. Is there anything we can do to fix this? eg. move its connection to the vertical riser lower? It's very annoying to find out that the install job isn't the greatest. Is this stuff that we should be taking up with the manufacturer/installer to try and get them to rectify? Or is it likely just poor practice that still fits within their obligations when doing the install? Sorry for all the questions, but there seems to be a lot more to this than I originally thought. Thanks again for all your help. Re: Tank / rainwater system missing filter 7Mar 15, 2013 9:15 pm I try to explain things so that the person that I hopefully help will understand what the basic principles and terminology are plus there are other people also reading this and many would have similar issues. For what its worth, your set up would be one of the better ones that I have seen but that is only because I see so many shockers. Yours is easy to fix. http://www.couriermail.com.au/ipad/tank ... 6024704679 There are tank cleaning businesses that recirculate and filter the water with little loss. If you do it yourself, you will obviously save money but you will lose a lot of water - but water is cheap. You will be restricted to not being able to tip the tank on its side but you have a big advantage in that you have another top inlet at the end opposite the pump. You are also fortunate to have a low fitted drain valve. Most tanks have a low fitted drain valve but it is usually connected to the pump!!! Just remove the inlets, open the tap and scrub the bottom of the tank with a yard broom to stir it up. When the tank is nearly empty, fit a pressure nozzle to a hose and give the bottom a blast. Tanks filling via standard systems often get a black tar like coating on the bottom and this requires some work but this depends on the area you live. As it is the first clean, I think that you should have a look at what is on the bottom. One of the big problems with standard rainwater harvesting systems is that the tank continues to receive water when the tank is full, putting more and more silt into the tank for no other benefit. You have an air gap on the tank overflow and this indicates that you are in QLD, probably under the BCC. If you are, then you would be getting quite a lot of heavy rain when the tank is already full. The filter cartridge is $160 to install PLUS ongoing replacement costs. The thing is...you apparently didn't have any early problems and having them now simply indicates that the tank needs a desludge. To reduce or even eliminate future desludges, why not consider this tank top inlet filter: http://www.tankfilter.com.au/ It is cheap but requires regular but simple maintenance. Repositioning the pump will cost and you are better off just desludging the tank and improving the water quality. If the builder is correct and there are 3 downpipes diverted to the tank, this means that there are two wet pipes that supply the vertical riser. If you had a heavy storm, the wet system pipes could flush a lot of accumulated muck into the tank and compromise the inlet filter I linked. I would fit either a trap or a flush outlet near the riser to capture and/or flush debris that accumulates in the wet pipes during times of lower rainfall. The first flush diverter is a lost cause. At the very most, it holds about 8 litres and if you lower it, it would reduce the capacity and it still wouldn't work anyway. The purpose of having a first flush diverter is to collect the initial dirtiest water that comes off the roof but that is down the other end of the wet pipe because wet system pipes remain flooded unless drained. If you do have 2 downpipes diverted to the vertical riser, then whoever fitted it probably thought that it was best to fit it where it is so that it services two downpipes. How stupid is that? They were also oblivious to the not inconsequential matter of required pipe flush velocity. The flush diverter should have a dripper at the bottom; does this work or is it blocked? If it is blocked, the retained water would not be the best. The leaf diverters are of more value to you at any rate. As for the poor install, I would let it go... The first flush diverter isn't regulated to be fitted so it works. The IO isn't regulated to be fitted so it works. The hard connections between the pump and the Rainbank (I am sure) are not compliant but the connection seems ok due to the connecting pipe having some flex by dipping down and then up to the Rainbank. If you weren't told of your options re a mains water switching device, then this has cost you quite a bit of money unnecessarily but it is well past the point now. Most plumbers don't know the regulations in their entirety. If you only use the pump to supply the toilet(s) and washing machine, I would be interested in knowing what model pump they have supplied. I have assumed it is a Davey. Cisterns are only regulated to fill at a minimum 6 litres per minute and washing machines fill slow. I see a lot of places where big, expensive pumps have been unnecessarily fitted. Not much you can do about it now though. Anyway, if you get the filter I linked and fit a sediment trap, the fix will cost less than $100. If you don't like the filter, then there are other options I can let you know about. EDIT: AS/NZS 3500.1 2003 Section 11 - PUMPS. Water services to buildings. 11.4 (B) refers to the requirements for "vibration eliminators" on a pump's suction and delivery sides to prevent undue stress on the pump and states: The pump's suction and delivery pipes shall be fitted with flexible couplings. Note that I have not copied the text word for word due to copyright but the above is accurate. Also, page 16 in the Davey Rainbank instruction manual linked below states: STEP 1 - PUMP POSITION evaluate and select the best pump site. this must be below the lowest anticipated level of the float switch and this level should be at least 100mm above the base of the tank to avoid sludge being drawn into the pump http://www.davey.com.au/site/DefaultSit ... Bank_0.pdf 3in1 Supadiverta. Rainwater Harvesting Best Practice using syphonic drainage. Cleaner Neater Smarter Cheaper Supa Gutter Pumper. A low cost syphonic eaves gutter overflow solution. Re: Tank / rainwater system missing filter 8Mar 17, 2013 11:19 am Thanks again for the very helpful reply. It's great to find someone going out of their way to really help a complete stranger - and no doubt like you say plenty of others will benefit from the info as well. I opened the top of the tank and had a quick peek inside and took some pictures which are below. It actually wasn't as filthy looking as I expected inside, but having never seen inside one before I have nothing to compare it to. There's a little black sludge on the bottom and some grime on the walls, and I can see some little particles floating around in the water, but nothing as bad as I was expecting. All this should be visible in the photos. Does it look worth emptying and desludging? Assuming it does still need a desludge, I just wanted to double check that a pressure hose (a Karcher, specifically) is ok to use, or is that likely to damage a protective coating or something similar? SaveH2O I would fit either a trap or a flush outlet near the riser to capture and/or flush debris that accumulates in the wet pipes during times of lower rainfall. Sorry, I'm still a little unclear on what you mean with this and can't imagine it in my head. Do you have a link to a picture so I can see what you mean? SaveH2O The flush diverter should have a dripper at the bottom; does this work or is it blocked? If it is blocked, the retained water would not be the best. The leaf diverters are of more value to you at any rate. I've unscrewed the cap on the first flush diverter periodically after heavy rain, and have never seen any debris in there at all. The dripper seems to work fine and the filter for it looks almost good as new. SaveH2O I would be interested in knowing what model pump they have supplied. I have assumed it is a Davey. Cisterns are only regulated to fill at a minimum 6 litres per minute and washing machines fill slow. I see a lot of places where big, expensive pumps have been unnecessarily fitted. Not much you can do about it now though. I believe it is a Davey like the rainbank system but we never received the manual for it so I can't say for sure. That filter you linked to looks great. I'm trying to source one near us and once I have we'll give it a try. Also, yes we are in Brisbane, though we actually fall under Moreton Bay Regional Council where we live. Thanks again - we greatly appreciate the time you're putting into helping us and all the advice you've been kind enough to share. Here are the photos of the inside of the tank: Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Re: Tank / rainwater system missing filter 9Mar 17, 2013 2:07 pm FIRST FLUSH DIVERTER A lot of people who have first flush diverters fitted with a new tank installs do not know that internal filters and small aperture drippers are high maintenance and it is good to know that you were aware of the need for a maintenance regime. The fact that yours is always clean demonstrates that the diverter is only filling with the settled water that has remained in the riser since the last rain. The leaf diverters will have 1mm mesh apertures and what gets through the mesh will be either grit that will mostly remain trapped in the wet system pipe or finer material that will travel up the riser with the increased flow velocity during heavier rain. Not having the diverter functioning is no big deal given that you have leaf diverters. One issue however is the dripper as most of these drain at 4 litres per hour. The volume of water that remains in the diverter plus the volume of water that remains in the riser and the two downpipes between the height of the bottom entry to the diverter to the bottom of the pipe at the riser's top 90 degree elbow would account for probably 15 litres. This means that you are losing 4 litres every hour plus another 15 litres (nearly 4 hours in reserve) in between rain or when it finishes raining. This accounts for several thousand litres of water lost every year from a fitting that doesn't work. I am very surprised at how clean the bottom of the tank is but this concerns me. Wet systems fed from multiple downpipes do put a lot of concentrated flow into the tank from the top during heavy rain and it stirs up the water on the bottom a fair bit. Diverting through the top inlet is actually the worst way to fill a tank. An undisturbed sediment layer acts as a filter as it is negatively charged and this allows it to lock away metals like lead as they are positively charged. The clean tank indicates that the source of the sediment clogging the washing machine filter and entering the cistern is most likely from three sources. 1) If the Y fittings are filters, they could be at their holding capacity and reconstituted debris is separating. 2) A build up of debris in the wet pipes is flushing through during heavy rain and settling around the submersible pump. 3) The pump is vacuuming the tank floor. See below. The second and third photos are of concern as they show that the pipe that takes water pumped from the pump to the Rainback is not vertical. This in turn indicates that the pump is sitting on an angle. This needs looking at as it is not right. Just reach in and try to reposition it if you can. Another concern is the black mark on the floor. Can you give this a quick brush over with a broom to make sure that it is sediment. For what the filter I linked costs, I think that it is well worth trying. Re the trap, if you have 3 downpipes diverted, then two of those feed the riser. To know whether the trap is worthwhile doing, I would need to know if two downpipes do connect to the riser and also know their connection (flow path) to the riser. They are easy to fit but maybe not worthwhile getting a plumber in. Checking the Y fittings, getting the inlet filter and looking at the slanted pump water pipe now needs to be the focus. There has been a few posts on Whirlpool lately where hard connected pumps and Rainbanks have given grief. 3in1 Supadiverta. Rainwater Harvesting Best Practice using syphonic drainage. Cleaner Neater Smarter Cheaper Supa Gutter Pumper. A low cost syphonic eaves gutter overflow solution. Re: Tank / rainwater system missing filter 10Mar 21, 2013 11:53 am One of the best threads I've read in ages. Great posts Re: Tank / rainwater system missing filter 11Mar 22, 2013 12:44 pm Definitely, I for one have greatly appreciated the help SaveH2O - Following the advice in your last post I'm going to have a look inside those Y fittings as soon as I can locate a spanner big enough to open them up! I'm also still chasing where to get that filter around Brisbane and will have a go at straightening the water pump pipe as well, though I suspect that may prove a little difficult being all the way up the other end of the tank. Thanks for all the help as always, and I'll update once I've managed to do some of the things above. Re: Tank / rainwater system missing filter 12Mar 22, 2013 3:22 pm StartingOut I'm going to have a look inside those Y fittings as soon as I can locate a spanner big enough to open them up! I'm also still chasing where to get that filter around Brisbane and will have a go at straightening the water pump pipe as well, though I suspect that may prove a little difficult being all the way up the other end of the tank. To reach the pipe, just unscrew the top meshed inlet next to it. Re the inlet down the other end that you have taken the photos through; does this normally have a meshed cover fitted to it? The WYE fittings do not look like normal filters but I am assuming that there will be a barrel filter inside. I could be wrong though. I don't know why they would have fitted WYE fittings if there was not a filter inside. Strange! Just having another look at the first photos and one photo looks as though the riser is a bigger pipe than the diverter and the overflow pipe but other photos suggest that they are the same size. If the riser is bigger, it will be a 100mm DWV pipe. These have an outside diameter of 110mm. I would be interested in knowing the size of this pipe. The circumference will be about 350mm from memory. I am really puzzled by the lack of sediment in the bottom of the tank. Leaf diverters do a really good job but I would have expected a lot more sediment after 2 years. I am wondering if the flow of water through the infeed pipes during heavy rain is causing the water and any light resuspended sediment to swirl around the oval tank during heavy rain when the tank level is low to start with and then discharge through the overflow once the tank is full. Most of the water would be coming from the wet system pipe (supplied by two downpipes) and this would have some minor forward carry as it flowed off the bottom of the infeed pipe although it will adhere to the curved downward surface (Coanda effect). If the two downpipes harvest let's say 30 sq m of roof each and there was heavy rain of 2mm per minute for a short duration, then this equates to 120 litres per minute or 2 litres per second infeeding from the wet pipe. The second infeed pipe however is angled and this pipe potentially gives a combined infeed during our reasonable storm of let's say 3 lps. This is substantial for a short tank and would cause significant disturbance. During times of normal rainfall, any fine organic matter would settle around the pump. It would be an interesting study of vorticity. 3in1 Supadiverta. Rainwater Harvesting Best Practice using syphonic drainage. Cleaner Neater Smarter Cheaper Supa Gutter Pumper. A low cost syphonic eaves gutter overflow solution. 18 90484 DIY, Home Maintenance & Repair But if it is a ground level open pit, then it is not a charged system. No surprises there. The pipes have obviously been altered and there would be a reason for this.… 3 31282 Grate, thank you! RexChan if thats the reason i could sleep well without thinking about additional cost. But 1st i'll need to read about NRV cleaning/replaing stuff. I… 7 31157 |