Browse Forums General Discussion 1 Oct 04, 2017 12:30 pm I have a particular problem with my cottage on tank water. The problem is that if electricity fails there is no water in the house. This is just what happened over the weekend whilst I had guests on short term stay. The guests were good about it and just went out for the day and came back after 4pm when the power was back on. However the risk of this happening again is forcing me to build in redundancy in case (as it will ) it happens again. As I see it I have three options: 1 Provide another line with water on gravity feed from a tank further up the hill with a three way valve. So in the case of failure just flick the lever on the valve and water supply will changeover from the pump to gravity feed. 2 as above but instead of gravity feed have a 12 volt (car battery) constant pressure pump for a flick over same as above. 3 Portable generator to power the pump whilst there is no power. I am leaning toward 1 as idiot proof but I will need another tank and roof for water collection (that means shed or a carport) 2 Would be cheapest for me as the pump is only about $100(at bunnings) and I already have spare boat battery. 3 Too messy and the cost of the generator Any ideas? Foremost Building Expert in Australia,assisting with building problems/disputes, building stage inspections,pre-contract review advice for peace of mind 200 blogs http://www.buildingexpert.net.au/blog Re: Tank water, providing redundancy. 2Oct 04, 2017 3:31 pm Kicking it a little more old school, we had a windmill that pumped to an higher up tank with the over flow going back to the original one. so it would be full whenever wind blew, no need for more collection areas. plus enviro friendly. image stolen for example but think: Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ JG King Lexington 240 Acreage build https://forum.homeone.com.au/viewtopic.php?f=31&t=87762 Re: Tank water, providing redundancy. 3Oct 04, 2017 5:40 pm Thanks emts but I don't have (nor want) windmill but you brought up a great point. I may not need extra roof area if I connect pump line to higher tank with a ball float valve. That way the high tank will always be full. Is there a way for auto switch over to higher tank supply if electricity is cut off to the pump? Another issue, I have Davey pressure pump(great pump) but when there is no power no water gets through. I would have thought that water would still flow through and fill my toilet cistern if my main tank level is nearly full. Foremost Building Expert in Australia,assisting with building problems/disputes, building stage inspections,pre-contract review advice for peace of mind 200 blogs http://www.buildingexpert.net.au/blog Re: Tank water, providing redundancy. 4Oct 04, 2017 8:11 pm building-expert Another issue, I have Davey pressure pump(great pump) but when there is no power no water gets through. I would have thought that water would still flow through and fill my toilet cistern if my main tank level is nearly full. Water will flow through a centrifugal pump but not through a high pressure cistern valve seal unless there is suitable head. The head also needs to close the seal otherwise it will keep flowing. The head difference between the tank and the cistern needs to be one metre IF the cistern is fitted with a Fluidmaster 400UK063 cistern valve (about $20 in the big green shed) and the standard high pressure seal has been replaced with the optional Very Low Pressure gravity fed (red) seal part number 242LP071. This seal also works fine with mains pressure, mine have been in for about 18 years now. http://www.plumbers-mate-sales.co.uk/fl ... 1136-p.asp If you go this route and can't find the gravity fed seal, I have them in stock and I will post you one gratias for the time you put into the forum. Re the no water supply issue when the power goes out, you have two choices additional to those already suggested. 1. You can install a header tank in the roof cavity and connect it to the cistern. This will also be quieter, reduce energy consumption and save on pump wear and tear. 2. You can install a decent size pressure tank that will supply a limited amount of water if the power fails but make sure that it is fitted with a butyl rubber bladder/diaphragm which is suitable for potable use. Rainwater is demineralised and if you use a pressure tank with a standard vinyl bladder or diaphragm, the pure water will draw every available contaminant including the elastomers which are toxic (and also taste bad) and which also causes the bladder to become brittle, the reason why so many pressure tanks used with rainwater fail. A pressure tank draws down about 35% of its stated capacity, the rest is air. When there is power, the pressure tank will supply water and the pump will not start until the water pressure drops to about 2 psi above the tank's air pressure. The pump will need a new pressure controller that will cut out at 70% of the pump's maximum head and at 2 psi above the tank's air pressure setting but the tank's pressure can be adjusted to suit the pump and the pressure controller. In other words, if the pump is rated at 55 psi and the tank is pressurised to 24 psi, the pressure controller needs to have a cut out setting of about 38.5 psi and a cut in setting of 26 psi so that it starts before the water runs out. Large pressure tanks are expensive, a quality 100 litre PressureWave costs about $480 discounted but if you are interested, I have a new high quality 165 litre tank here still in the box that was going to be used to store RO water in a coffee shop but they opted for a smaller tank due to space restrictions. It is nearly $700 new but you can have it for $450 if interested. https://www.bluewatertanks.com.au/brand ... -Wave.html Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ I also have a new still in the box Pressure Wave 80 litre tank, you can have that for $260 if interested. The drawback to using a pressure tank as an emergency supply is that the tank won't necessarily be near full when the power fails but that is why a large one is better. 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 water, providing redundancy. 5Oct 05, 2017 8:02 am Thank you Save H2O, not only are you very knowledgeable but also kind and generous. I will mull it over next week when I am there ( if I can get away from the boat and fishing). I am leaning toward 12v pressure pump and battery and a simple 3way valve. To activate in the event of power loss it will be a simple lever flick. I have once built kindergarten with emergency gravity feed water tank on the roof and that was fine but here I do have a hill at rear of the house and space for a boat shed (to be built). (and I don't want the tank on the roof) Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Foremost Building Expert in Australia,assisting with building problems/disputes, building stage inspections,pre-contract review advice for peace of mind 200 blogs http://www.buildingexpert.net.au/blog Re: Tank water, providing redundancy. 6Oct 05, 2017 8:29 am Just realised that you have a flat roof...so much for installing a header tank in the roof cavity! The 12V option would be good. 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 74811 From what I know about water tanks (I've been working with a client on them for a few years now) is this - The concrete can last a lifetime if they don't crack for some… 2 6485 If you can calculate the reasonable charged head from let's say 100mm below the gutter to the top of where the vertical riser's horizontal discharge pipe will be, that… 11 14468 |