Rheem 136-1826 - Manual (Page 20)

It is recommended that a gate valve be installed in the cold water supply line adjacent to the heater. If Local Codes
require a check valve - provisions must be made for thermal expansion.
A minimum pressure of 30 PSIG must be maintained in the system to prevent damage to the heater due to lack
of water circulation caused by vapor formation at suction side of the system pumps.
NOTE: Should the cold water supply be interrupted, for any reason, the gas supply must be manually shut off to
prevent heater damage. When the service is restored the lines must be vented to eliminate accumulated air.
b. WATER
Water piping should be installed according to the local code requirements, ASHRAE, ASPE and BOCA
or other regulatory agencies.
COLD WATER SUPPLY
The cold water supply piping, to the heater must be adequate to handle the design load requirements of the hot
water system. The following table illustrates the flow and minimum pipe sizes.
Model
Size
136
181
264
331
399
512
627
726 Flow
GPM
85
90
90
90
90
90
90
90 Model
Size
825
926
962
1083
1125
1178
1287
1337
Min
Pipe
NPT
1-1/4
1-1/2
1-1/2
1-1/2
1-1/2
2
2
2
Flow
GPM
22
30
42
53
63
82
85
85
Min
Pipe
NPT
2
2-1/2
2-1/2
2-1/2
2-1/2
2-1/2
2-1/2
2-1/2
Model
Size
1413
1467
1570
1630
1758
1826 Flow
GPM
90
90
90
90
90
90
Min
Pipe
NPT
2-1/2
2-1/2
2-1/2
2-1/2
2-1/2
2-1/2
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