INSTALLATION – WATER HEATER
40
CIRCULATED HOT WATER FLOW AND RETURN SYSTEM
An 884 series continuous flow water heater can be installed as part of a circulated hot water flow and return
system in a building.
Notes:
•
the preset outlet temperature setting of the water heater must be set to at least 60°C.
Water should not be circulated from a water heater with a temperature setting of less than 60°C. In New
Zealand an approved UV sterilisation or chlorine disinfection system may be used if the temperature
setting of the water heater is less than 60°C.
•
temperature controllers should not be installed with a water heater as part of a circulated hot water flow
and return system.
The exception is with an Ez-Link System dual installation, where:
AU – only a Kitchen controller can be installed, which
MUST NOT
be below 60°C to meet the
requirements of the Plumbing Standard.
NZ – can have a Kitchen controller and / or Bathroom controller(s) installed and must also have an
approved UV sterilisation or chlorine disinfection system installed. This is required as the maximum
temperature controller settings are less than 60°C, and the requirements of the Plumbing Standard
must be met.
Warning:
The controller must be left on during periods the circulator may operate.
The circulator must be:
•
sized and set to provide a minimum flow rate of 3.0 L/min through the recirculated 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.
Warning:
An 886 series continuous flow water heater
must not
be installed as part of a circulated hot
water flow and return system in a building.
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.
