Install Instructions

Part Number 550-142-902/1016
CGi
GAS-FIRED WATER BOILER — SERIES 3 — Boiler Manual
23
Water piping — multiple zones (continued)
4c
Figure 18 Zoning with circulators
— return water 130°F or higher.
Figure 19 Zoning with zone valves
— return water 130°F or higher.
1Boilerisolation(balancing)valves
2 Flow/check valve
3Systemorzonecirculator
5Zonevalve
6Drainvalve
9 Relief valve
10Automaticairvent(withdiaphragm‑typeexpansiontank),orcon-
nect to tank fitting (closed-type expansion tank). DO NOT use an
automatic air vent when using closed-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 expansiontank,if used (For
closed-type expansion tank, pipe from top of air separator to tank
fitting as in Figure 17.)
13Airseparatorandautomaticvent,ifused(Notethatthellvalve
must always be connected to the expansion tank, regardless of loca-
tion of expansion tank circulator or air separator.
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
Figures 20 – 24, as applies. Failure to prevent sustained low return water temperature to
the boiler could cause corrosion of the boiler sections, resulting in severe personal injury,
death or substantial property damage.