Here is a picture of the Davey Rainbank I installed sometime back. It’s part of a water tank system I have at home of 24,000 litres and has been working well for 6 months. The system was installed to reduce our water bills and provide an independent water supply for any soft collapse scenario or local or state level water system failures that might arise and it’s a great feeling to be watering our food crops in wicking beds or flushing our toilet using rainwater.
To provide redundancy in case of failure, contamination or leaks the system is divided into four, including two main parts which are both used for watering and can use either pumps or gravity, an isolated 3600L tank as a backup storage and a very small tank capturing some water off an isolated shed. Each of the four systems sources their water from different parts of the roof(s). Each tank in each system can be isolated.
To provide redundancy in case of failure, contamination or leaks the system is divided into four, including two main parts which are both used for watering and can use either pumps or gravity, an isolated 3600L tank as a backup storage and a very small tank capturing some water off an isolated shed. Each of the four systems sources their water from different parts of the roof(s). Each tank in each system can be isolated.
So all was going well until I had my plumber over who shut the mains supply off. It was a hot day. I thought I have my tanks connected I will water the garden. I went to turn on one of the taps connected to the Davey Rainbank and nothing. I checked the power and tanks water levels - all good thus we have a problem. A quick google search and a read of the Davey user manual and FAQs I realise my system design had a major fault, my Davey Rainbank required mains pressure to work. Any scenario where mains water fails or is turned off my system fails - not a good prepping outcome.
This little exercise, though quite embarrassing, reinforces some very basic but key prepping lessons.
So where to now? I want that system to be able to supply water from the tanks without mains pressure. So it is out with the Rainbank (selling second hand shouldn’t be too hard) and in with something else.
Options include going with a mechanical automatic mains / pump diverter. Here are two options that popped up on a whirlpool discussion:
http://www.irrigationwarehouse.com.au/prod299.htm
http://www.acquasaver.com.au/
Or go completely manual which should work in my case as I have a reasonable volume of storage and I check water tank levels regularly. I can even move water around from other parts of the system.
If I want a manufactured one valve system I might choose this:
http://www.mainrain.com.au/MainRain%20eBrochure/MainRain_eBrochure.pdf
Or I can simply add two manual valves, one on the mains line and one on the pump. I might only need one if I wish to rely on the pumps backflow protection but this means if I need to service the pump I would need to shut the mains water as well too shutting down this parts of the system.
I will also need a new pressure controller for my submersible pump. So the question now is to Davey or not to Davey… off to the forums.
This little exercise, though quite embarrassing, reinforces some very basic but key prepping lessons.
- never assume anything, make sure what you think is true is i.e, check the manual / specs / FAQs I just assumed a mains tank diverter system would work without main supply (I mean who would design it not to work - Davey obviously)
- test your systems in a realistic way prior to the event you have designed them for i.e. turn off the mains and see if the system works.
- get a second opinion of an expert and check the reviews. We have a Davey fire pump on our property that is used to pump water to a header tank. It has just kept going and going for year and years. I made a purchase choice based on my experience with the brand rather than the performance of the product in question which is a very different technology than their fire pumps.
So where to now? I want that system to be able to supply water from the tanks without mains pressure. So it is out with the Rainbank (selling second hand shouldn’t be too hard) and in with something else.
Options include going with a mechanical automatic mains / pump diverter. Here are two options that popped up on a whirlpool discussion:
http://www.irrigationwarehouse.com.au/prod299.htm
http://www.acquasaver.com.au/
Or go completely manual which should work in my case as I have a reasonable volume of storage and I check water tank levels regularly. I can even move water around from other parts of the system.
If I want a manufactured one valve system I might choose this:
http://www.mainrain.com.au/MainRain%20eBrochure/MainRain_eBrochure.pdf
Or I can simply add two manual valves, one on the mains line and one on the pump. I might only need one if I wish to rely on the pumps backflow protection but this means if I need to service the pump I would need to shut the mains water as well too shutting down this parts of the system.
I will also need a new pressure controller for my submersible pump. So the question now is to Davey or not to Davey… off to the forums.
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