INSTALLATION – WATER HEATER
19
CIRCULATED HOT WATER FLOW AND RETURN SYSTEM
A Solahart in-series gas booster can be installed as part of a circulated hot water flow and return system in a
building. The preset outlet temperature setting of the water heater must be set to at least 60°C, or at least
70°C to meet the requirement of AS 3498, or at least 70°C if the water temperature decreases by more than
5°C through a circulated hot water flow and return system due to heat loss in the ring main. Water should not
be circulated from a water heater with a temperature setting of less than 60°C.
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, and
either thermostatically and / or timer controlled.
The circulator
must not
be set to operate continuously, i.e. 24 hours per day.
Temperature Limiting Device
A temperature limiting device cannot be installed in circulated hot water flow and return pipe work. The
tempered water from a temperature limiting device cannot be circulated. Where a circulated hot water flow
and return system is required in a building, a temperature limiting device can only be installed on a dead leg,
branching off the circulated hot water flow and return pipe.
If circulated tempered water were to be returned back to the water heater, depending on the location of the
return line connection on the water supply line to the water heater, then either:
water will be supplied to the cold water inlet of the temperature limiting device at a temperature
exceeding the maximum recommended water supply temperature, or
when the hot taps are closed no water will be supplied to the cold water inlet of the temperature limiting
device whilst hot water will continue to be supplied to the hot water inlet of the temperature limiting
device.
These conditions may result in either water at a temperature exceeding the requirements of AS/NZS 3500.4
being delivered to the hot water outlets in the ablution areas, or the device closing completely and not
delivering water at all, or the device failing. Under either condition, the operation and performance of the
device cannot be guaranteed.
LEGEND
LEGEND
Circulated Hot Water Flow and Return
In-series Gas Booster as part of a Solar Water Heater Installation
REDUCING HEAT LOSSES
The hot water line from the in-series gas booster and the pipe work between the solar storage tank and the
in-series gas booster must be insulated in accordance with the requirements of AS/NZS 3500.4. The
insulation must be weatherproof and UV resistant if exposed. The insulation must be fitted up to the
connections on the both the underside of the water heater and the solar storage tank.
from solar
storage tank
