Lochinvar Outdoor Knight Boiler 151-286 - Manual (Page 39)

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Operating information
General
How the boiler operates
The outdoor boiler uses an advanced stainless steel heat
exchanger and electronic control module that allows fully
condensing operation. The blower pulls in air and pushes flue
products out of the boiler through the heat exchanger and flue
piping. The control module regulates blower speed to control
the boiler firing rate. The gas valve senses the amount of air
flowing into the boiler and allows only the right amount of gas
to flow.
How the control module operates
The SMART SYSTEM control module receives inputs from
boiler sensors and external devices. The control module
activates and controls the blower and gas valve to regulate heat
input and switches the boiler, Domestic Hot Water (DHW),
and system pumps on and off as needed. The user programs
the module to meet system needs by adjusting control
parameters. These parameters set operating temperatures
and boiler operating modes. Boiler operation can be based on
boiler outlet water temperature, boiler inlet water temperature,
system temperature, a 0-10V signal or ModBus, depending on
the parameter settings.
Control inputs and outputs
Room thermostat
There are three (3) heat/loop demand connections available on
this control. These inputs tell the boiler to provide water for
space heating. Each demand connection has its own set point
and outdoor air reset curve. When multiple demands have a
call for heat the control will give priority to the demand with
the highest set point.
Example: Assume that both heat/loop demand
1 and heat/loop demand 2 have a call for heat.
Demand 1 has a set point of 110°F. Demand 2 has a set point
of 140°F. The boiler will regulate the system temperature to
140°F until Demand 2 has been satisfied. Once Demand 2 has
been satisfied the boiler will provide 110°F water to the system.
SMART SYSTEM Multi-temp loop control
The outdoor boiler is capable of producing up to three (3) set
point temperatures to meet different space heating demands.
This device controls the temperatures of up to three (3)
separate loops, based on the settings for the three (3) heat/loop
demands (reference Lochinvar kit RLY30086).
0 - 10V input (set point or power)
The outdoor boiler can be controlled by a Building
Management System (BMS) provided that either an external
energy management system is installed that reduces the boiler
water temperature as the heating load decreases, the boiler
is not used for any space heating, or the boiler is part of a
modular or multiple boiler system having a total input of
300,000 Btu/hr or greater.
The control can be configured by the installer to use a 0 - 10
Vdc signal to either control set point or firing rate.
The outdoor boiler can also be programmed to accept a call for
heat from a 0 - 10V signal, reference the Outdoor Knight Boiler
Service Manual for a detailed explanation of this procedure.
DHW priority
The SMART SYSTEM control allows the connection of a DHW
thermostat or tank sensor to the low voltage connection board.
When a tank sensor is connected, the DHW thermostat input
is ignored. When a boiler is programmed for DHW Normal
Mode, the maximum firing rate can be limited to match the
input rating of the indirect tank coil.
DHW / space heating (SH) cycling
If a DHW call for heat is received while a space heating call is
in progress, and the DHW is in Normal Mode, the control will
start the DHW pump and shut the boiler pump off. The system
pump will remain on. For stand-alone boilers, if the space
heating call is still active while the DHW call is in operation,
the control will wait for 30 minutes (time adjustable by
installer) then it will switch back to the space heating demand.
There is a timer to switch from space heating to DHW and a
timer to switch from DHW to space heating. The control will
switch back and forth until one of the heat demands end.
Programmable controlling sensor
The control module is programmed to use the outlet sensor
as the control sensor by default. If a system supply sensor
is connected, the control automatically uses it as the control
sensor. For stand-alone boilers, the control sensor can be
changed by the installer to the inlet sensor. If the inlet sensor
is chosen as the controlling sensor, it is recommended that the
system supply sensor be installed in the system supply in order
to provide the best control of the inlet temperature.
Anti-cycling
After the burner turns off, the control will delay the next
burner cycle for a set time period (time is adjustable by the
installer). The time delay will be bypassed if the inlet water
temperature drops too far during the delay.
Boiler and system pump control
The boiler pump will run whenever the burner is firing, unless
the DHW is programmed for Normal Mode and the boiler
is heating the DHW tank. The boiler pump will run during
Freeze Protection Mode as well. It will continue to run for a
short time after the burner turns off or the Freeze Protection
Mode ends.
The system pump will run whenever there is a space heating
call for heat, or the boiler goes into Freeze Protection Mode. It
may be programmed to run during a DHW call for heat when
the DHW is programmed for Zone Mode. It will continue
to run for a short time after the end of the heat demand
or the Freeze Protection Mode. The system pump can be
programmed to run continuously if desired, except during
outdoor shutdown and/or a DHW call for heat.
ƽ CAUTION
When multiple temperature loops are
used, mixing valves are required for the
protection of any low temperature loops.
Outdoor Knight Boiler Installation & Operation Manual