Specifications

INSTALLATION – WATER HEATER
19
FROST PROTECTION
The water heater has a frost protection system. The frost protection system will protect the water heater from
damage, by preventing ice forming in the waterways of the water heater, in the event of freezing conditions
occurring.
The frost protection system will be rendered inoperable if electrical power is not available at the water heater.
Damage to the water heater caused by freezing of the pipe work to or from the water heater is not covered
under the Rheem warranty. Refer to AS/NZS 3500.4 for precautions to be taken for installations in frost
prone areas. The water heater is not suitable for installation in areas where the ambient temperature falls
below -20ºC (including wind chill factor).
The cold water line to the water heater must be insulated with suitable thickness insulation if freezing
conditions are likely to occur. The insulation must be fitted to the underside of the water heater and be
weatherproof and UV resistant if exposed.
MAINS WATER SUPPLY
Where the mains water supply pressure exceeds that shown in the table below, an approved pressure
limiting valve that does not have non return valve characteristics (such as an RMC PSL series valve) is
required and should be fitted as shown in the installation diagram (refer to page 22).
Model
W27
Relief valve setting
1000 kPa
Expansion control valve setting
850 kPa
Max. mains supply pressure
With expansion control valve
650 kPa
Without expansion control valve
800 kPa
Min. mains supply pressure *
160 kPa
* minimum water supply pressure required to achieve the rated flow
and performance
Notes:
It is not recommended to install this water heater with a low pressure water supply.
A minimum water supply pressure of 160 kPa is required to achieve the rated flow and performance of
the water heater.
If sludge or foreign matter is present in the water supply, it is recommended a suitable filter be
incorporated in the cold water line to the water heater.
This water heater is not suitable for connection to bore water or spring water unless a water treatment
device is fitted.
Refer to “Water Supplies” on page 12 for further information on water chemistry.
WATER TEMPERATURE DIAGRAMS
Note: Water initially discharged by this water
heater at start-up may be at a temperature of up
to 70°C before the water heater normalises to its
preset outlet temperature.
Temperature Limiting Devices – refer to “Hot
Water Delivery” on page 20.
Factory preset outlet temperature setting is:
874 series 60°C