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9. Boiler Protection Features
a. Supply Water Temperature High Limit
The boiler is equipped with independent automatic
reset and a manual reset High Limit devices. The
automatic reset high limit is provided by a supply
manifold mounted Limit Device. The automatic
high limit is set to 200°F. The Sage2.1 monitors
a supply water temperature sensor that is also
mounted in the supply water manifold and supplies
an internal, manual reset high limit. The manual
reset high limit Hard Lockout is set at 210°F.
Additionally, if the supply temperature rises faster
than the degrees Fahrenheit per second limit a soft
lockout is activated.
b. High Dif
ferential Temperature Limit
The Sage2.1 monitors the temperature difference
between the return and supply sensors. If this
difference exceeds 90°F the control begins to
reduce the maximum fan speed. If the temperature
difference exceeds 100°F the control will shut the
unit down. The unit will restart automatically once
the temperature difference has decreased and the
minimum off time has expired.
LWCO NOTE
i. The Sage2.1 shuts down the boiler when
either
the supply water temperature is too high
or supply to return temperature differential
temperature is too high. This ensures the boiler
is shutdown in the event of a low water level
or low water ow condition.
ii. Some codes and jurisdiction may accept these
integral features instead of requiring a low
water cutoff. ADHERE TO ALL LOCAL
CODE REQUIREMENTS. Contact your
local code inspector prior to installation. If
required, a LWCO four-position wire harness
connection is provided for an external LWCO
kit (p/n 102097-01) to be added. If the LWCO
opens, the boiler will shut down and an open
limit indication and error code is provided.
If the limit installed is a manual reset type,
it will need to be reset before the boiler will
operate.
c. Return Temperature Higher Than Supply
Temperature (Inversion Limit)
Th
e Sage2.1 monitors the supply and return
temperature sensors. If the return water temperature
exceeds the supply water temperature for longer
than a limit time delay the Sage2.1 shuts down the
boiler and delays restart. If the inverted temperature
is detected more than ve times the boiler manual
XII. Operation (continued)
reset Hard Lockout is set. This condition is the
result of incorrectly attaching the supply and return
piping.
d. External Limit
An external limit control can be installed between
terminals 11 and 12 on the low voltage terminal
strip. Be sure to remove the jumper when adding an
external limit control to the system. If the external
limit opens, the boiler will shut down and an open
limit indication and error code is provided. If the
limit installed is a manual reset type, it will need
to be reset before the boiler will operate.
e. Boiler Mounted Limit Devices
The Sage2.1 monitors individual limit devices:
pressure switch, high limit device, condensate level
switch, low water cutoff (optional), fuel gas pressure
switches (optional) and external limit (optional).
If any of these limits opens, the boiler will shut
down and an individual open limit indication is
provided.
f. Stack High Limit
The Sage2.1 monitors the ue temperature sensor
located in the vent connector. If the ue tempera-
ture exceeds 194°F the control begins to reduce
the maximum fan speed. If the ue temperature
exceeds 204°F the control activates a manual reset
Hard Lockout.
g. Ignition Failure
The Sage2.1 Control monitors ignition using a
burner mounted ame sensor. In the event of a
failed ignition the control continuously retries with
a 5 minute time delay after 5 consecutive retries.
h. Central Heating System Frost Protection
When enabled, Frost Protection starts the boiler and
system pump and res the boiler when low outside
air temperatures are sensed. The Sage2.1 control
provides the following control action when frost
protection is enabled:
Table 27: Frost Protection
Device Start
Temperatures
Stop
Temperatures
Boiler & System
Pump
Outside Air < 0°F
Supply Water < 45°F
Outside Air > 4°F
Supply Water > 50°F
Boiler Supply Water < 38°F Supply Water > 50°F
NOTE
The Sage2.1 primarily provides freeze protection for the
boiler. Since the Sage2.1 only controls the system and
boiler circulators individual zones are not protected. It is
recommended that the boiler be installed in a location that is
not exposed to freezing temperatures.
A. Major Features (continued)
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