About Your Water Heater; Model Type; Water Heater Operation; Gas Boosting For A Solar Water Heater - Rheem 18 Owner's Manual & Installation Instructions

MODEL TYPE

®
The Rheem electronic continuous flow gas water heater model you have chosen is for outdoor installation
only. This model has an extended warranty (refer to
The water heater has a maximum preset outlet temperature setting of:
874 series 60 C
876 series 48 C
Notes:
The 876 series water heater is marked "THIS APPLIANCE DELIVERS WATER NOT EXCEEDING 50°C
IN ACCORDANCE WITH AS 3498" on the front panel. This model;
must not be installed as an in-series gas booster water heater to a solar water heater, as water

temperature greater than 50°C can be delivered from the water heater contravening its compliance
to AS 3498.
must not be installed with a Water Star water heater as water temperature greater than 50°C can

be delivered from the system.
The 874 series of water heater may be installed as an in-series gas booster water heater to a solar
preheat water heater. For information relating to the function and operation of the solar water heater,
refer to the Owner‟s Guide and Installation Instructions supplied with the solar water heater.
When installed as a gas booster to a solar preheater, the 874 series water heater:
can deliver water at temperatures up to 75 C for a Premier Loline and Loline pumped system and a

Hiline thermosiphon system and possibly higher temperatures from a Premier Hiline thermosiphon
system.
during periods of low solar energy gain, will boost the water temperature automatically to a

minimum 60 C when required.

WATER HEATER OPERATION

The water heater operates automatically, heating water as it passes
through the water heater. When a hot tap is opened, the gas burners
ignite to provide immediate heating of the water. The heat produced by
the burner is transferred to the water through the heat exchanger. The
water is heated to a constant temperature by the automatic adjustment
of the gas supply to the burner to suit the water flow rate (refer to
"Temperature Control"
on pages 9 to 38). The gas burners extinguish
when the hot tap is closed.
Automatic safety controls are fitted to the water heater to provide safe
and efficient operation.

GAS BOOSTING FOR A SOLAR WATER HEATER

Water stored in the solar storage tank passes through the gas booster
water heater when a hot tap is opened. The gas booster water heater
is for heating water at times of low solar energy gain, such as during
cloudy or rainy weather, or during winter months.
Solar heated water can reach temperatures up to 75 C for a Premier Loline and Loline pumped system and
a Hiline thermosiphon system and possibly higher for a Premier Hiline thermosiphon system. The gas
booster water heater operates automatically. When the solar heated water temperature is 58 C or higher, the
flow passes through the gas booster water heater without boosting. When the solar heated water
temperature is below 58 C, the gas booster water heater heats the water to a minimum temperature of 60 C.

ABOUT YOUR WATER HEATER

"Warranty"
on page 80).
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