Expansion Tank - Weil-McLain GOLD CGt Manual

GOLD CGt Gas-Fired Water Boiler — Boiler Manual
4b
Water piping — single-zone system

Expansion tank

Diaphragm-type or bladder-type
expansion tank — Figure 16
1. Ensure expansion tank size will handle boiler and
system water volume and temperature. Tank must
be located in boiler return piping as close to boiler
as possible, before inlet side of circulator. See tank
manufacturer's instructions for details.
2. Install an
Figure 16 Diaphragm- or bladder-type expansion tank
Piping to single-zone system using diaphragm-
type or bladder-type expansion tank. See Table
5 for piping sizes.
System
return
Isolation valves
(typical)
Return line
(Pipe to 3-way
valve as shown)
Relief valve
(Pipe to drain)
Circulator
(install only on
boiler return line,
as shown)
071018
Part Number 550-110-290/0501
as shown.
automatic air vent
Undersized expansion tanks cause system water to be lost from relief valve and makeup water
to be added through fill valve. Eventual section failure can result.
Use or
Figure 16 Figure 17
130 °F. For systems with low return water temperature possible, such as converted gravity
systems and radiant heating systems, refer to the special piping suggestions of pages 24-25.
Failure to prevent low return water temperature to the boiler could cause corrosion of the
boiler sections or burners, resulting in severe personal injury, death or substantial property
damage.
Cold water fill
System
supply
Automatic air vent
(pipe to tapping
behind boiler supply
tapping as shown)
Closed-type expansion tank — Figure
17
1. Ensure expansion tank size will handle boiler and
system water volume and temperature. See tank
manufacturer's instructions for details.
2. Connect tank to ½" NPT tapping located behind
supply outlet, using ½" NPT piping. Pitch any
horizontal piping up towards tank 1 inch per 5 feet
of piping.
only for single-zone systems designed for return water at least
Figure 17 Closed-type expansion tank
Piping to single-zone system using closed-
type expansion tank. See Table 5 for piping
sizes.
To diaphragm System
expansion tank
return
Isolation valves
(typical)
Return line
(Pipe to 3-way
valve as shown)
Relief valve
(Pipe to drain)
Circulator
(install only on
boiler return line,
as shown)
071019
Closed type
expansion tank
(piped to vent tapping
behind boiler supply)
Cold water fill
System
supply
21