Potable Space Heating - Rheem HG Series Use & Care Manual

Supplemental instructions for gas water heaters
installed in potable/space heating applications.
Local codes or plumbing authority requirements may vary from the instructions or diagrams provided in
this manual and take precedent over these instructions.
Hot water
supply to
house
Hot water
supply to
From HOT
heating
outlet on
unit
water heater
Tee fitting for vertical hot
water supply lines.
From HOT
Hot water
outlet on
supply to
water heater
house
Hot water supply
to heating unit
Tee fitting for horizontal hot
water supply lines.
Typical Piping Diagram for Combination Potable/Space Heating Installation
Spring loaded check valve in
heating unit hot water supply line
and cold water return line (not
supplied with water heater)
NOTE: This valve is incorporated in
some heating units. Refer to the
installation instructions supplied
with specific heating unit to
determine if it is required.
Isolation valve in hot water
supply line to heating unit
(not supplied with water heater)
See diagrams above for proper
pipe application for vertical
or horizontal supply lines
Gas line to water heater
Gas water heater
Temperature and
pressure relief valve
discharge line
Combination Potable and Space Heating Application
Tee fitting must be installed as shown.
This insures that any air in the water
lines will be purged through the domestic
water faucets and showers.
WARNING: When this system
requires water for space heating at
elevated temperatures (above 125°F.), a
mixing or tempering valve must be
installed in the hot water supply line to
the house in order to reduce the scald
hazard potential.
WARNING: Any piping or components
used in the installation of this water
heater in a combination potable and
space heating application must be
suitable for use with drinking water.
WARNING: If this water heater is
installed in an application intended to
supply domestic hot water needs and
hot water for space heating purposes,
do not connect the heater to an existing
heating unit or components of a heating
system that have previously been used
with a non drinking water system. Toxic
chemicals such as those used for boiler
treatment may be present and will
contaminate the drinking water supply
causing possible health risks. Never
introduce toxic chemicals, such as
those used for boiler treatment, into
this system.
Air vent
Domestic hot water supply
Incoming cold water supply
Mixing or tempering
valve (refer to
warning above)
Isolation valve in
cold water return
line from heating
unit (not supplied
with water heater)
Cold water return line
from heating unit
Hot water
supply line into
heating unit
Drain valve
(not supplied
with water
heater)
6 air gap
Heating unit
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