Weil-McLain CGi Series 3 Installation And Maintenance Manual page 21

CG i
GAS-FIRED wATER BOILER- sERIEs a -
Boiler Manual
4b
Water piping - single-zone system
IAcAunoNI
Undersized expansion tanks cause system water to be lost from relief valve and makeup water
to be added through till valve. Eventual section failure can result
Diaphragm-type or bladder-
type expansion tank
(Figure 16)
t.
Ensure expansion tank size will handle ooiler and
system water volume and temperature. Tank must
be located in boiler return piping as close to ooiler
as possible, before inlet side of circulator. See tank
manufacturer's instructions for details.
2.
Install an automatic air
vent
as shown.
Closed-type expansion tank
(Figure
17)
t.
Ensure expansion tank size will handle ooiler and
system water volume and temperature. See tank
manufacturer•s instructions for details.
2.
Connect tank
to 'h''
NPT
tapping located behind
supply outlet, using
'h"
NPT
piping. Pitch any
horizontal piping up towards tank I inch per 5 feet
of piping.
I&
WARNING!
Use Figure
16
or Ftgure
17
only for single-zone systems designed for return water at least I
30°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
24-29.
Failure to
prevent low return water temperature to the ooiler could cause corrosion of the ooiler sections
or burners, resulting in severe personal injury, death or substantial property damage.
Figure
16
Diaphragm- or bladder-type expansion
tank - Piping to single-zone system
using diaphragm-type or bladder-type
expansion tank.
See
Table 6 for piping
sizes.
Isolation
valve
Circulator
From
system
Cold
water
fill
To
DIAPHRAGM
expansion tank
and fittings
To
system
Automatic
air vent
•Alternate
location
Figure 17 Closed-type expansion tank - Piping
to s ingle-zone system us ing closed-
type expansion tank.
See
Table
6
for
piping sizes.
Relief
valve
Circulator
From
system
CLOSED
type
expansion tank
--.......~.....-
Isolation
valve
To
system
•Alternate
location
Part
Number 550-142-780/0712
2 1