P/N 42-9450 8/08 Copyright 2008 Hydrotherm
Page 15 KN INSTALLATION AND OPERATION INSTRUCTIONS
Water piping (continued)
Figure 11 Suggested piping — multiple boilers — primary/secondary piping, reverse-return boiler headers
Multiple boilers, primary/secondary
Sizing and ow control
Size circulators to provide the ow needed for the individual zones.
Provide ow/check valves where shown to prevent gravity circulation or
forced ow in idle zones.
DHW operation, when required
e piping shown throughout this manual allows for domestic water
heating without ow through the heating loop(s). is is important for
summertime operation of DHW tanks.
Make sure to incorporate ow/check valves as shown. ese prevent forced
ow in idle zones.
LEGEND • • • • • • •
1 KN boiler
2 Boiler circulator
3 System circulator
5 Indirect- red DHW tank
(when used)
6 DHW circulator
7 Flow/check valve
8 Cold water ll line
9 Expansion tank (shown with diaphragm-type — see
page 12 for piping a closed-type tank) Expansion tank
(shown with diaphragm-type — see page 12 for piping
a closed-type tank)
10 Air separator with automatic air vent (Replace air vent
with piping to the tank ing on closed-type expansion
systems.)
11 Low water cut-o (when required)
12 Extra high limit (when required)
16 Boiler postpurge circulator (see page 11) KN
-
2 only
17 Header sensor, required
Isolation valve
Temperature gauge
5
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