9
8.
Boiler Temperature Regulation
a. Overview
Based on the call for heat type, the Sage2.1
selects a firing rate target temperature setpoint.
Sensed temperature is compared to this Setpoint
to both adjust firing rate output and along with the
corresponding “Diff Above” and “Diff Below”
settings cycle the boiler.
b.
Central Heat Setpoint
The Central Heat Setpoint is fixed at the contractor
selected value unless Outdoor Air Reset is enabled
or a “Setback” thermostat is connected. The value
of this setpoint is set up based on the type and
quantity of radiation installed.
c. Domestic Hot Water (DHW) Setpoint
The DHW setpoint is fixed at the user selected
value unless a “setback” thermostat is connected.
The value of this setpoint is established based on
the requirements of the indirect water heater.
i.
Domestic Hot Water Priority (DHWP)
When domestic hot water priority is selected
and there is a DHW call for heat, the system
pump will be turned off (when system pump
run pump for parameter is set for “Central Heat
Optional Priority”) and the DHW pump will
be turned on. Additionally, if outdoor reset is
active, the active setpoint is adjusted to be at
least greater than a DHW Setpoint. Priority
protection is provided to ensure central heat
supply in the case of excessive or failed DHW
call for heat.
d.
Outdoor Air Reset
If an outdoor temperature sensor is connected
to the boiler and Outdoor Reset is enabled,
the Central Heat setpoint will automatically
adjust downwards as the outdoor temperature
Xii. Operation (continued)
increases. When the water temperature is
properly matched to home heating needs there
is minimal chance of room air temperature
overshoot. Excessive heat is not sent to the room
heating elements by “overheated” (supply water
temperature maintained at High Limit setting)
water. Reset control saves energy by reducing
room over heating, reducing boiler temperature
& increasing combustion efficiency and reducing
standby losses as a boiler and system piping cool
down to ambient following room over heating.
i.
Boost Time
When the Central Heat Setpoint is decreased by
Outdoor Air Reset settings the Boost function
can be enabled to increase the setpoint after the
central heat demand is not satisfied for longer
than the Boost Time minutes the operating
temperature setpoint is increased by 10 F. This
process will continue until either heat demand
is satisfied (indoor air is at desired temperature)
or a maximum setpoint is reached. Once the
heat demand is satisfied, the operating setpoint
reverts to the value determined by the Outdoor
Air Reset settings. If Boost Time is zero, then
the boost function is not used.
ii.
“Setback” Setpoints
User adjustable setback setpoints are provided
for both Central Heat and DHW demands. The
Setback setpoint is used when the EnviraCOM
thermostat is in “leave” or “sleep” modes.
When setback is “on” the thermostat setback
setpoint shifts the reset curve to save energy
while the home is in reduced room temperature
mode. The Honeywell VisionPro IAQ (part
number TH9421C1004) is a “setback”
EnviraCOM enabled thermostat.
A.
Major Features
(continued)
Summary of Contents for Alpine ALP080
Page 40: ...40 Figure 29 Condensate Trap and Drain Line V Condensate Disposal continued ...
Page 56: ...56 VIII Electrical continued ...
Page 57: ...57 VIII Electrical continued Figure 35 Wiring Connections Diagram ...
Page 58: ...58 Figure 36 Ladder Diagram VIII Electrical continued ...
Page 64: ...64 Figure 39 Modular Boiler Direct Vent Termination X Modular Installation continued ...
Page 65: ...65 Figure 40 Modular Boiler Concentric Vent Termination X Modular Installation continued ...
