Boiler Piping
Connect the expansion tank to an air separator
only if the air separator is located on the suc-
tion side (inlet) of the system circulator.
Always locate and install the system fill con-
nection at the same location as the expansion
tank connection to the system.
Diaphragm Expansion Tank
Always install an automatic air vent on the top
of the air separator to remove residual air from
the system.
Closed-Type Expansion Tank
It is recommended to pitch any horizontal pip-
ing upwards toward the expansion tank 1 inch
per 5 feet of piping. Use 3/4” piping for the
expansion tank to allow air within the system
to rise.
DO NOT install automatic air vents on a
closed-type expansion tank system. Air
must remain in the system and be
returned to the expansion tank to pro-
vide an air cushion. An automatic air
vent would cause air to be vented from
the system resulting in a water-logged
expansion tank.
Circulator
The PRESTIGE Excellence is supplied with a
Boiler circulator that provides circulation for
central/space heating (CH) and domestic hot
water (DHW) production. See Graph 2 on page
81 for pressure drop and minimum flow rate
through the boiler.
Sizing Primary Piping
See Figs. 9 through 12 on pages 20 and 21, for
recommended piping arrangements based on
various applications. Size the piping and sys-
tem components required in the space heating
system, using recognized design methods.
System Piping - Zone Circulators
Connect the PRESTIGE Excellence to the sys-
tem piping as shown in Fig. 9 page 20 when
zoning with zone circulators.
The installer must provide a separate circulator
for each zone of space heating.
To ensure an adequate flow rate through
the PRESTIGE Excellence, the boiler
supply and return piping size must be a
minimum of 1 inch.
System Piping - Zone Valves
Connect the PRESTIGE Excellence to the system
piping as shown in Fig. 10 page 20 when zoning
with zone valves. The primary / secondary piping
ensures that the boiler loop has sufficient flow.
To ensure an adequate flow rate through
the PRESTIGE Excellence, the boiler sup-
ply and return piping size must be a min-
imum of 1 inch.
System Piping - Through Boiler
In new or retrofit applications in which
primary/secondary arrangement is not utilized, the
PRESTIGE Excellence allows this flexibility due
to a lower boiler pressure drop, see Graph 2 on
page 81.
Figure 11, page 21 illustrates a multiple zone
valve system with a single system/boiler circu-
lator. A by-pass loop with a pressure differential
valve must be installed on the system piping.
Figure 12, page 21 illustrates a single zone utiliz-
ing the boiler circulator as the system circulator.
NOTICE
CAUTION
NOTICE
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