Weil-McLain CGi 4 Series Manual page 23

CGi
SERIES 4 — GAS-FIRED WATER BOILER —
4c
Water piping — multiple zones
Figure 18
Boiler isolation (balancing) valves
1
Flow/check valve
2
System or zone circulator
3
Zone valve
5
Drain valve
6
9 Relief valve
Part Number 550-142-302/0520
Zoning with circulators
— return water 130°F or higher.
For systems with possible low return-water temperature (such as converted gravity systems,
radiant heating systems and heat pump systems), refer to the special piping suggestions of
, as applies. Failure to prevent sustained low return water temperature to
Figures 20 – 24
the boiler could cause corrosion of the boiler sections, resulting in severe personal injury,
death or substantial property damage.
Boiler Manual
Figure 19
Automatic air vent (with diaphragm-type expansion tank), or con-
10
nect to tank fitting (closed-type expansion tank).
automatic air vent when using closed-type expansion tank. It would
allow air to leave the system, causing waterlogging of the expansion
tank.
Fill valve
11
Diaphragm-type or bladder-type expansion tank, if used (For
12
closed-type expansion tank, pipe from top of air separator to tank
fitting as in .)
Figure 17
Air separator and automatic vent, if used (Note that the fill valve
13
must always be connected to the expansion tank, regardless of loca-
tion of expansion tank circulator or air separator.
(continued)
Zoning with zone valves
— return water 130°F or higher.
DO NOT
use an
23