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Circulated Hot Water Flow & Return Systems
The solar storage cylinder of a solar water heater should not be installed as part of a circulated hot water
flow and return system in a building. The benefits of solar gain will be significantly reduced and energy
gained from the sun lost through the pipe work.
If a circulated flow and return system is required, the gas booster can be installed as part of a circulated hot
water flow and return system. In this case, it is necessary to connect the return line to the inlet of the gas
booster and in parallel with the solar storage cylinder hot water outlet (
refer to “Circulated Flow & Return
Plumbing Diagrams” on page 28).
If the gas booster is mounted on the solar storage cylinder (integrated gas booster), then a suitable tee must
be installed at the inlet to the gas booster. The flexible hose from the solar storage cylinder hot water outlet
and the circulation return line is connected to the tee.
An Aquamax CF20-60 or CF26-60 model continuous flow in-series gas booster can be installed as part of a
circulated hot water flow and return system in a building provided the following requirements are met:
The gas boosters preset outlet temperature setting is set to a
minimum
of 70°C to meet the
requirements of AS 3498.
The circulator must be sized and set to provide a
minimum
flow rate of 3.0 L/min through the circulated
hot water flow and return system.
The circulator must be thermostatically and / or timer controlled.
The circulator
must not
be set to operate continuously, i.e. 24 hours per day.
It has been determined that hot water demand can be met by the gas booster (the gas booster has
been suitably sized).
For circulated hot water flow and return systems, a temperature limiting device can only be installed on a
dead leg which branches off the circulated hot water flow and return pipe.
Warning:
Installing a temperature limiting device in the circulated flow and return pipe work, or
circulating tempered water from a temperature limiting device may cause water to be delivered to ablution
areas at a temperature exceeding the requirements of AS/NZS 3500.4.
Circulated Flow & Return Plumbing Diagrams
Circulated Flow & Return Plumbing Diagram
– Gas Boosted Solar System with Integrated Gas Booster
