Boiler Manual
Part Number 550-110-593/1099 19
Typical piping — multiple-zone installations
Figure 11
Zoning with circulators
— return water 130 °F or higher.
Figure 12
Zoning with zone valves
— return water 130 °F or higher.
1Boiler isolation (balancing) valves
2Flow/check valve
3System or zone circulator
5Zone valve
6Drain valve
9Relief 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 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 10.)
13 Air separator and automatic vent, if used (Note that
the fill valve must always be connected to the
expansion tank, regardless of location 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 13 – 17, 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.
59308
10
Cold
water
fill
11
12
9
GOLD
CGa
ZONE 2
ZONE 1
1
11
2
2
3
1
66
13
59309
10
Cold
water
fill
11
12
9
GOLD
CGa
ZONE 2
ZONE 1
1
6
11
6
1
5
13
Alternate
circulator
location