Burnham K2WTC - Page 102

102
107774-01 - 9/17
7. Warm Weather Shutdown (WWSD)
Some boilers are used primarily for heating buildings,
and the boilers can be automatically shutdown when
the outdoor air temperature is warm. When outside air
temperature is above the WWSD setpoint, this function
will shut down the boiler, boiler and system pump.
8. Energy Management System (EMS) Interface
 A factory congured RS485 Modbus interface is
available for Energy Management System (EMS)
monitoring when not used for Multiple Boiler
Sequencer Peer-To-Peer Network. Consult factory for
points list or if this interface must be used in addition
to the boiler Peer-to-Peer Network.
9. Circulator Control
The control manages the operation of the built-in
boiler pump, built in diverting valve, and installer
supplied system pump (if used). The system pump
maybeconguredtorunorremainoffwhenacall
for domestic hot water is present (default is for the
system pump to run). Circulators and diverting valve
are automatically energized for a 20 second exercise
period after not being used for longer than 7 days.
Circulator exercise helps prevent pump rotor seizing.
10. Multiple Boiler Sequencer Peer-To-Peer
Network
The Control includes state-of-the-art modulating lead-
lag sequencer for up to eight (8) boilers capable of auto
rotation, outdoor reset and peer-to-peer communication.
The peer-peer network is truly “plug and play”. This
boiler may only be used as a slave in such a system.
Consult the factory for additional information on using
this boiler in multiple boiler systems.
XIII. Operation (continued)
B. Water Temperature Regulation
1. Priority Demand
The Control accepts a call for heat (demand) from
multiple places and responds according to it’s
“Priority”. When more than 1 demand is present the
higher priority demand shown in Figure 13.1 is used
to determine active boiler settings. Active “Priority”
is displayed on the “Boiler Status” screen.
Priority
Status Screen
Display
Boiler Responding to:
1st Domestic Hot
Water
DHW call for heat is on and selected
as the priority demand. DHW is
higher priority than Central Heat
during the DHW priority time.
(default = 60 minutes)
2nd Central Heat Central Heat call for heat is on and
there is no DHW demand or DHW
priority time has expired.
3rd Auxiliary Heat Auxiliary Heat call for heat is on and
there is no Central Heat or DHW
demand. (NOTE: May be user
selected to be higher priority than
Central Heat.)
4th Frost
Protection
Frost Protection is active and there
is no other call for heat.
5th Warm
Weather
Shutdown
(WWSD)
WWSD is active and the boiler
will not respond to central heat
demands. DHW demand is not
blocked by WWSD.
6th Standby There is no demand detected.
Table 13.1: Order of Priority
4. Auxiliary Heat Setpoint
Auxiliary Heat is a second heating demand that may
be used to serve either lower temperature radiation or
warmer heat demands such as fan coils. This demand
may only be initiated via the Sage Zone Panel. Upon
an Auxiliary Heat call for heat the setpoint is either the
user entered Auxiliary Heat Setpoint or is automatically
adjusted as Outdoor Air Reset.
5. 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 increases. When the water
temperature is properly matched to 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
too high a setting) water. Reset control saves energy
by reducing room over heating, reducing boiler
temperature&increasingcombustionefciencyand,
reducing standby losses as a boiler and system piping
cool down to ambient following room over heating.
6. Boost Time
When the Central Heat Setpoint is decreased by
Outdoor Air Reset settings the Boost function can
be enabled to increase the setpoint in the event that
centralheatdemandisnotsatisedforlongerthanthe
Boost Time minutes. The Boost feature increases the
operating temperature setpoint by 10°F (5.6°C) every
20minutes(eldadjustable)thecentralheatdemand
isnotsatised.Thisprocesswillcontinueuntilheat
demandissatised(indoorairisatdesiredtemperature),
2. Setpoint Purpose
The Control starts and stops the boiler and modulates
the boiler input from minimum (MBH) to maximum
(MBH) in order to heat water up to the active setpoint.
The setpoint is determined by the priority (Central
Heat or Domestic Hot Water) and as described in the
following paragraphs.
3. Central Heat Setpoint
Upon a Central Heat call for heat the setpoint is
either the user entered Central Heat Setpoint, or is
automatically adjusted by Outdoor Air Reset or, an
Energy Management System (EMS) supplied setpoint.