Browse Forums General Discussion Re: Linking 2 water tanks, why doesn't this work? 8Mar 11, 2014 4:18 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: Linking 2 water tanks, why doesn't this work? 12Mar 14, 2014 12:10 am 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: Linking 2 water tanks, why doesn't this work? 14Mar 15, 2014 12:59 am 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: Linking 2 water tanks, why doesn't this work? 15Mar 15, 2014 10:16 am 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: Linking 2 water tanks, why doesn't this work? 17Mar 19, 2014 5:35 pm acem8 Fitting a simple non-return valve as shown in the diagram below has stopped that happening and now I am able to run off both tanks at the same time or one at a time. SaveH2O The house pump is not flooded at the big tank's lower water depths and it needs to have a check valve fitted on a flooded section of pipe. This must be before the balance line for obvious reasons. I would have fitted the non return valve before the balance line so that you can transfer water between tanks. As is, you can only transfer from the smaller tank to the larger tank PROVIDED that there isn't a check valve already fitted somewhere near the larger tank (as I believe there is) that is already stopping water flowing from the smaller tank to the larger tank. With the new check valve fitted in the balance line, you will not be able to use it as a balance line although the house pump will be able to use the balance line to access the smaller tank. acem8 Also the 3-4m of head pressure above the cottage pump means the main house pump does not draw on the cottage pump. The cottage pump cannot draw on the main house pump because I have now installed the non-return valve. Correct...but the cottage pump also cannot draw from the big tank due to the new check valve. acem8 Question - can I leave BV3 permanently open and the main house pump will take from whichever tank has the higher water level? All pipe diameter are the same, the main tank has a slightly easier flow path but then the small one isn't complicated. The above is assuming that there is an 'unknown' check valve near the large tank that is stopping water flowing from the small tank to the larger tank. BV3 is redundant for any purpose other than to isolate the smaller tank from the house tank. Most water will be drawn from the tank with the greater head relative to the house pump, particularly during low flow demand. 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: Linking 2 water tanks, why doesn't this work? 18Mar 20, 2014 12:54 pm I choose to put the non-return valve in the current position because it was easy to do for test purposes - it just screwed in to the ball valve BV3. I could move it to where you suggest but I have 2 reservations; 1) The position suggested would be 400mm below soil level and behind a bush which makes access in the future difficult. Are these valves service items that can go wrong? 2) After major rain events the level in the big tank will be higher than the overflow in the small tank. If BV4 is not closed I could slowly lose water from the big tank? 3) If the big tank ran out of water and we closed BV4 and then ran both properties off the small tank, is there a possibility of creating an air lock in the system if the small tank water level was below the suggested position of the non-return valve? ie. cottage pump pulls all the water out of the balance line. Re: Linking 2 water tanks, why doesn't this work? 19Mar 20, 2014 4:46 pm It is only an educated guess when one cannot see the topography. Some things suggested are not always feasible. At the moment and assuming that there is a check valve near the large tank that prevents water being transferred into that tank, the current set up only prevents water from being transferred between tanks. While having a facility to transfer water would be handy, it probably matters little to your situation as it is something that you can get around if needed. The big tank should not lose water if the new check valve does its job. Nevertheless, you would be wise to close BV3 whenever the house pump is not drawing from the smaller tank. I was concentrating on air pockets and air flushing rates because of earlier advice that there was not another check valve fitted near the bigger tank. You will not get entrained air or air pockets unless a tank outlet draws a vortex at a low water level. The air has to be infused. Provided the tanks water levels are sufficient, this won't happen. The unknown check valve was preventing water draining back from the house pump to the big tank but when you fitted the balance line, you created an unrestricted flow path to the smaller tank. Depending on the height of the water in the smaller tank in relation to the height of the house pump, air could/would have been ingested into the house pump when the height of the house pump and the smaller tank's water level reached equilibrium. The pump noises would have been a result of the pump trying to run with some air in the pump. It is strange as to why the pressure switch did not stop the pump when it detected low pressure. There has to be another check valve already fitted near the big tank that prevents water flowing back from the house pump to the big tank. If there isn't, then water would have been flowing back prior to creating the new flow path to the smaller tank. There being another check valve is evidenced by the fact that you are unable to transfer water from the smaller tank to the bigger tank. 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: Linking 2 water tanks, why doesn't this work? 20Mar 21, 2014 9:58 am Is the smaller tank's outlet valve that supplies the pump(s) a 32 mm valve or do you have a 32 mm (27 mm ID) poly pipe connected to a 1" or even a 3/4" outlet valve? 3in1 Supadiverta. Rainwater Harvesting Best Practice using syphonic drainage. Cleaner Neater Smarter Cheaper Supa Gutter Pumper. A low cost syphonic eaves gutter overflow solution. That was always going to be a challenge and a test of patience. Full marks to your mate. Did you discuss the wet area near the trampoline? 16 17287 6 11470 |