Burnham ALPINE Installation, Operation And Service Instructions page 93

Xii. Operation (continued)
7. Priority Demand
The Sage2.1 accepts a call for heat (demand) from
multiple places and responds to each demand according
to it's relative importance. When more than one demand
is present at one time the more important demand is
selected as the "priority" demand and is used to operate
the boiler and pumps. The selected priority demand
is displayed on the boiler "Status" screen (see Figure
55). For example, when Domestic Hot Water (DHW)
demand has priority the firing rate setpoint is set equal
to the DHW Setpoint, the DHW, Boiler and System
pumps respond to a DHW demand. Table 26 lists
available priority demands in order of highest priority
to lowest priority:
Table 26: Order of Priority
Status Screen
Priority
Display "Priority"
Order
Sequencer Control
st
1
Domestic HW
nd
2
rd
3 Central Heat
Frost Protection
4 th
th
5 Warm Weather
Last Standby
The Sage2.1 accepts a demand from the following
inputs:
a. Sequence Control
A Sequencer Control demand is received when the
boiler is connected to a Sequence Master using an
Ethernet cable to connect the "Boiler - to - Boiler
Communication Network" RJ45 connection.
Sequence Control is the priority when the boiler is
connected to a Sage2.1 with the Sequence Master
"enabled" (refer to Modular Installation, Section X,
G, 4 for additional information). Networked boilers
display "Sequence Control" as the priority even if
there is no current Call For Heat. The boilers are
"slaves" waiting to fired based on the Sequence
Master's demand inputs.
Boiler Responding to:
The boiler is connected to the
Sage2.1 modular boiler network.
The boiler accepts demand from
the Sequencer Master.
DHW demand has been received
and selected as the priority
demand. DHW is always higher
priority than Central Heat and when
DHW priority is enabled is higher
priority than the Sequencer Control.
Central Heat call for heat is on and
has been selected as priority.
Frost Protection is active and there
is no other call for heat. Frost
protection will be a higher priority
than Sequencer Control if the
Sequence Master has no active call
for heat.
Warm Weather Shutdown (WWSD)
is active and the boiler will not
respond to central heat demands.
DHW demand is not blocked by
WWSD.
There is no demand or there is
demand and the boiler is not firing
because the sensed temperature is
greater than setpoint.
b. Domestic Hot Water
A domestic hot water demand is received by wiring
a demand contact to the low voltage terminal
strip "DHW Temp Switch" terminals. The boiler
responds to a domestic hot water demand with a
domestic hot water setpoint and pump settings.
Domestic HW demand has priority over Central
Heat demand and has priority over Sequencer
Control when DHW Priority is enabled. Refer to
Adjusting Parameters, Paragraph E for additional
information.
c. Central Heat
The Sage2 accepts a Central Heat demand from
the below listed sources. When a Central Heat
demand has priority the boiler responds to central
heat setpoint and pump settings. Outdoor reset
and Setback Setpoint settings are available during
a Central Heat priority:
i. Conventional Thermostat
A heating request is received by simply wiring
a thermostat to the low voltage terminal strip
"Heating T-Stat" terminals.
ii. EnviraCOM Enabled Thermostat
A heat demand and setpoint "setback" request
is received by wiring an EnviraCOM enabled
thermostat to controller terminals "D, R & C".
For example, when a VisionPro EnviraCOM
thermostat is connected a call for heat and
"sleep" and "away" information is received.
Additionally, the home owner is alerted to a
boiler problem by a thermostat red LED and
error message.
iii. External Modular Boiler Controller or Building
Automation System (BAS)
A heating request is received from an external
control by wiring a heat demand to the low
voltage terminal strip "Heating T-Stat"
terminals and a firing rate to the Remote
Firing Rate terminals. Additionally, parameter
selections are required. Refer to Adjusting
Parameters, Paragraph E for additional
information.
d. Frost Protection Call For Heat
Frost Protection demand is generated by system
protection logic (refer to Operation, Paragraph A,
9 h for more information). Frost protection will
be a higher priority than Sequencer Control if the
Sequence Master has no active call for heat.
e. Warm Weather Shutdown (WWSD) Setpoint
When enabled, the boiler will not be allowed to
start if the outside temperature is greater than the
WWSD setpoint. WWSD is the priority demand
when active and there is no DHW demand.
9