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AQUA PLUS indirect-fired water heaters — Product Manual
Domestic water piping
Figure 2 DHW piping
Piping overview
THERMAL EXPANSION TANK — If a
backflow preventer, check valve, or pres-
sure reducing valve is piped on cold water
inlet of water heater, you must install an
expansion tank on cold water supply line
to prevent normal thermal expansion
from repeatedly forcing open T&P relief
valve.
The T&P relief valve is not intended for
constant duty, such as relief of pressure
due to repeated normal system expan-
sion. Refer to expansion tank manufac-
turer’s instructions for proper sizing.
Failure to comply could result in severe
personal injury, death or substantial
property damage.
General applications
1. Figure 2 — This piping configuration can be used in
most cases, except where local codes require special
components or piping not illustrated.
2. Some codes may require the items listed as optional,
such as a vacuum breaker on the inlet line, or re-
circulation piping.
Massachusetts applications
1. For Massachusetts code applications, or as
required elsewhere by local codes, install the fol-
lowing options.
a. Thermal siphon on DHW inlet and outlet.
b. Vacuum breaker on domestic water inlet line.
c. Recirculation — Massachusetts code applica-
tions require recirculation piping or heat-traced
piping if the distance from the water heater to
the furthest fixture exceeds 100 feet. See page 8
for details.
Figure 3 Piping connection sizes
Model
AQUA PLUS
Connections
(inches NPT)
DHW
in/out
Boiler water
in/out
Recirculation
tapping
35
¾ 1 ¾
45
¾ 1 ¾
55
¾ 1 ¾
85
1 1 ¾
105
1 1 ¾
Part number GL-E223-ADOC 0311
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