INSTALLATION – WATER HEATER
23
HOT WATER DELIVERY
This water heater can deliver water at temperatures which can cause scalding.
It is necessary and we recommend that a temperature limiting device be fitted into the hot water piping to
any ablution and public areas such as a bathroom, ensuite or public amenities when a Multipak water heater
is installed to reduce the risk of scalding. The installing plumber may have a legal obligation to ensure the
installation of this water heater meets the delivery water temperature requirements of AS/NZS 3500.4 so that
scalding water temperatures are not delivered to a bathroom, ensuite or other ablution or public area.
The temperature limiting device used with a continuous flow gas water heater should have:
•
a specified ‘minimum temperature differential’ between the hot water inlet and the tempered water outlet
of no greater than 10°C, and
•
a specified ‘maximum permitted pressure variation’ in the supply between the hot water inlet and the cold
water inlet of no less than 15%.
Refer to the specifications of the tempering valve.
TEMPERATURE LIMITING DEVICE
A temperature limiting device cannot be installed in circulated hot water flow and return pipe work, unless it
is specifically designed to do so, such as the Rheem Guardian warm water system. 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.
Note: a Multipak/50 system with the words
“THIS APPLIANCE DELIVERS WATER NOT EXCEEDING
50
O
C IN ACCORDANCE WITH AS3498”
on the front panel of the water heater complies with the
requirements of AS3500.4 for 50
o
C maximum delivery temperature and requires no further tempering for
these applications.
