Tee fitting for vertical hot
water supply lines.
Hot water
supply to
house
From HOT
outlet on
water heater
Hot water
supply to
heating
unit
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.
Tee fitting for horizontal hot
water supply lines.
From HOT
outlet on
water heater
Hot water
supply to
house
Hot water supply
to heating unit
Combination Potable and Space Heating Application
Tee fitting must be installed as shown.
This ensures that any air in the water lines
will be purged through the domestic water
faucets and showers.
DANGER: When this system
requires water for space heating at
elevated temperatures (above 125°F
[52°C.]), 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.
DANGER: 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.
DANGER
:
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.
CO
LD
HO
T
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 check valve is
incorporated in some heating units.
Refer to the installation instructions
supplied with specific heating unit to
determine if it is required.
See diagrams above for proper
pipe application for vertical
or horizontal supply lines
Gas line to water heater
Cold water
return line from
heating unit
Hot water
supply line
into heating unit
Heating unit
Isolation valve in cold
water return line from
heating unit (not
supplied with water
heater)
Mixing or
tempering
valve (refer
to warning
above)
Water Heater Jacket
Temperature and pressure
relief valve discharge line
Drain valve
(not supplied with water
heater)
Temperature and Pressure
Relief Valve
Isolation valve in hot water supply line
to heating unit
(not supplied with water heater)
Incoming cold
water supply
Domestic hot water supply
Air vent
15
6” Air Gap
Combustion Air Inlet
Openings
Thermal Expansion
Tank (if required-not
supplied with water
heater)
Heat Trap
6” Min.
Shut-Off
Valve