(Taken directly from notes made as I've discovered, expanded and used the system)
1. House and Garden supply
2. Pump box layout
Two Unconnected Water Storage Systems
The system suffers from having been added to over time, it is a little over-complicated but is at least manageable and has some flexibility.
The two systems must never be connected, except to prime the well pump. Use of household water for priming will not be necessary once the return from the tanks is completed (dotted line in the diagram).
Household Domestic Rainwater System
This system provides rainwater to the house, and two external taps one at the front beside the verandah near the smaller kitchen window and the other at the rear next to the septic tank. It also provides top-up water for the hydronic heating/cooling buffer tank.
There are two primary collection tanks:
House tank (approximately 15,000 litres)
Garage tank (approximately 15,000 litres)
There is one supplementary storage tank:
Paddock tank nearest the carport (33,000 litres)
Each tank has an isolation valve (valves C, E and F). To facilitate pumping water from the House tank to the other two tanks there is an additional isolation valve D at the House tank.
How To Prime Pump A
Pump A operates under “flooded” condition and does not normally require priming. If air enters the system and prevents the pump from starting automatically when taps are opened then the pump will need to be primed.
Open the exterior house tap to the left of the pump box (next to the septic tank).
Press and hold the priming button on the pump controller inside the pump box.
Release the button when water flows from the tap. The pump will restart.
Close the tap.
Water for household use may be sourced directly from any or all of the three tanks by opening their isolation valves. Normally this would be the House tank alone by closing valves D, E and F. To switch to the Garage tank and allow the House tank to refill naturally from rainwater, close valves B and C and open valves D and E. Similarly to switch to the Paddock tank open valves D and F.
In the event of a power outage (no pumps), very low pressure water can be made available to most house taps under gravity by opening valves B and D. If the House tank is low then close valve C and open valve B and either valve E or F depending on which tank has the highest level.
Check the 20 micron filter every 6 months and the 5 micron filter every year or two or if low water pressure indicates a possible blockage. The filters are pleated whole-of-house filters and should deliver up to 140lpm when operating correctly. They can be carefully cleaned manually a few times before they need to be replaced entirely. They cost around $70 each from the local supplier in town.
They are intended to screen out debris and sediment but not bacteria. Single outlet 0.4 micron filters will be installed in the kitchen and wash basins to screen bacteria and very fine sediment.
House isolation valves
The kitchen is supplied via a separate line from the pump box and the two lines can now be isolated via new valves O and P. The kitchen supply line also continues on to the Annex where there is a capped pipe end situated on the outside of the workshop wall next to the annex water tank. The reworking of the system included fitting a pressure reduction valve.
Valve L must always remain open to provide top-up water to the hydronic system via the one-way pressure-activated valve M (identified by the pressure gauge). Valve L should be closed if a leak is detected in the hydronic system, in which case also switch the heating/cooling system off via the manual switch in the hall toilet. Switching the geo exchange system off via the breaker in the fuse box will stop heating the domestic hot water tank in the laundry.
Transfer between tanks
Water may be transferred between any tanks under gravity, or from the House tank to either of the other two via Pump A, without affecting house supply.
The tank overflow outlets are not necessarily all at the same height so opening all isolation valves permanently will decrease the total water storage capacity. The lowest overflow outlet is the House tank followed by the Garage tank and the Paddock tank is the highest.
In the event that all tanks are low, opening all isolation valves plus valve D will maximise rainwater collection by averaging the levels across all three tanks, but only until the House tank (lowest overflow outlet) becomes full.
To transfer water under gravity between the Garage tank and the House tank open valve E then valves C and D to connect the two tanks. Valves A and C may be left open for normal household supply. Ensure that valve B remains closed.
To pump water from the House tank to the Paddock tank, assuming valves A and C are open for normal household use, open valve F at the Paddock tank and then open valve B in the pump box. The pump should start. Ensure that valve D remains closed. Close valves B then F either when water appears at the overflow outlet of the Paddock tank or when the level in the House tank has fallen to the lowest usable level. The pump should stop. In the later case (House tank reaches lowest useful level), follow example (1) to transfer water from the garage tank to the house tank.
Opening valves B and D together will open a loop causing the pump to start and run continuously.
With the house tank valve C open, opening valve B and another tank valve (E and/or F) will start the pump running continuously, potentially draining the house tank through the overflow of the other tank.
It is important therefore to keep all valves closed and only open those valves required to perform the function in mind. If the pump is running while no taps are open then check all valve states.
Garden and Paddock Well Water System
This system extracts water from the shallow well approximately three metres deep at the rear of the residence to supply garden and paddock use and two storage tanks. An in-line 200 micro metre filter has been installed intended only to prevent debris from clogging sprinklers, spayers etc.
It takes a particularly wet Spring to bring the water table to it’s highest level approximately 50cm from the top of the well. Over a normal summer it can drop to 1.5 metres or more. The diameter of the well is about 1 metre giving a maximum capacity of about 2300 litres (average capacity: about 1500 litres). From empty it takes 24 hours or more for the level to come back up to the average level, so the average ingress rate is about 1 litre per minute.
How to Prime Pump B
When air gets into the pipes it will be necessary to prime the well pump (Pump B).
Connect a hose from the Pump Box Tap to the Priming Inlet at the well.
Open valve I then valve B. Pump A may start at this point. If it does it’s probably because valve D is open.
Open the pump box tap. Pump A should start if it didn’t already in step 2.
Open the garden tap located to the right of the pump box, not the tap next to the septic tank. Water should flow (this is water from the household system flowing through the well line and through Pump B).
Connect power to Pump B and open valve G.
If the Pump B doesn’t start press the priming button on the Pump B controller.
Release the priming button. Pump B should restart and continue running.
Monitor the garden tap (step 4). Water flow should increase significantly after some seconds.
Close valve I then valve B, close the pump box tap and disconnect the hose.
Close the garden tap then close valve G. Pump B should stop.
Remove power from Pump B.
To run sprinklers from any of the four garden taps pressure is required and this is currently only possible using well water directly via Pump B. Ensure that the paddock tanks/taps isolation valve H (next to the garden tap near the driveway) is closed whenever running sprinklers in the house yards.
Pumping well water to the tanks
To pump water to either tank, open valve H and the tank's isolation valve (at the tank).
Do not open both tank isolation valves (J and K) simultaneously because this will drain water out of the Paddock High tank through the lower tank overflow outlet.
Gravity Pressure Supply
By leaving valves H and either J or K open, gravity pressure water is available at the garden and paddock taps to fill containers or for pressure spray washing etc.
Return Line from Tanks to Pump B
Yet to be installed, this line will connect a point just above valve H to the Priming Inlet point above valve I (dotted line in schematic diagram). Closing valve H and opening valve I will provide priming water to Pump B simplifying the priming process and at the same time enable water to be pumped from either tank to the garden taps.
The well one-way foot valve N ensures that water does not drain from the tanks into and overflow the well when the pump is not running. Some additional valves may be required to isolate the well water if pumping continues to draw well water while sourcing tank water.
The leak was located under the verandah slab outside the 1905 kitchen extension in the rural poly pipe that feeds the garden tap nearby. The 100mm damaged section was cut out and an inline joiner was inserted.
It appears to me from inspection that the pipe must have been damaged before or during installation decades ago and may even have been leaking already although very very slowly. I suspect the new pump that replaced the old one 18 months prior increased line pressure which eventually opened up the split in the pipe further over time.