INSTALLATION AND OPERATION INSTRUCTIONS
1-24
SL 26-260 G3, SL 40-399 G3 MODULATING GAS BOILERS
1.6.2 Installation Rules
If the installation involves small loads, as in typical zoned baseboard heating applications,
use of a buffer tank is recommended. To aid in temperature transition from hot to cool
loads, a 3-way mixing valve can be placed at the entrance to the cool load (this will also
provide floor protection). This will permit immediate circulation of mixed flow into the cool
loop.
Figure 28: Primary/Secondary piping concept with simultaneous setpoint calls.
Always
ensure that loads sensitive to high temperatures (e.g. radiant floor) are protected using
appropriate means such as a manual mixing valve, or an aquastat (set to130°F, for
example) wired to the boiler’s auxiliary interlocks.
Figure 29: Two pump, two load - parallel piping concept
WARNING
Do not use automotive-type
ethylene or other types of
automotive glycol antifreeze,
or undiluted antifreeze of
any kind. This may result in
severe boiler damage. It is the
responsibility of the Installer to
ensure that glycol solutions are
formulated to inhibit corrosion
in hydronic heating systems
of mixed materials. Improper
mixtures and chemical additives
may cause damage to ferrous
and non-ferrous components
as well as non-metallic, wetted
components, normally found
in hydronic systems. Ethylene
glycol is toxic, and may be
prohibited for use by codes
applicable to your installation
location. For environmental
and toxicity reasons, IBC
recommends only using non-
toxic propylene glycol.
NOTE
The boiler, when used in
connection with a refrigeration
system, must be installed so
the chilled medium is piped
in parallel with the boiler with
appropriate valves to prevent the
chilled medium from entering the
boiler.
NOTE
The boiler piping system of a hot
water boiler connected to heating
coils located in air handling units
where they may be exposed to
refrigerated air circulation must
be equipped with flow control
valves or other automatic means
to prevent gravity circulation
of the boiler water during the
cooling cycle.
