Weil-McLain CGi Series 3 Installation And Maintenance Manual page 25

CG i
GAS-FIRED wATER BOILER- sERIEs a -
Boiler Manual
4d
Piping - low temperature systems
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Figure 20 Primary/secondary piping
Zoning wtth circulators
Figure 21 Primary/secondary piping
Zoning w1th zone valves
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1 Boiler isolatio n (balancing) valves
2 Flow/ check valve
3 System o r zone circulator
4 System temperature gauges
5 Zone valve
8 Drain valve
7 System tem perature valves (see instruc-
tions to the left for adjusting valves}
8 Blend temperature gauge
71023
71022
9 Relief valve
10 Automatic air vent {with diaphragm -type expansion tank), or
connect to tank fitting (closed-type expansion tank). DO NOT
use an automatic air vent when using d osed-type expansion tank.
It would allow air to leave the system, causing waterlogging of
the expansion tank.
11 Fill valve
12 Diaphragm-type or bladder-type expansio n tank, if used (Fo r
dosed-type expansion tank, pipe from top of air separator to
tank fitting as in Figure 17.}
13 Air separato r and automatic vent, if used (No te that the fill valve
must always be connected to the expansion tank, regardless of
location of expansion tank, circ ulato r or air separator.)
Part Number 550-142-780/0712 25