29
5
Field wiring
(continued)
Thermostat
1. Connect the room thermostats or end switches (isolated
contact only) to Heat/Loop Demand 1, 2, or 3, as shown
in FIG. 5-3.
2. Install the thermostat on the inside wall away from
influences of drafts, hot or cold water pipes, lighting
fixtures, television, sunlight, or fireplaces.
3. Thermostat anticipator (if applicable):
a.
If connected directly to boiler, set for 0.1 amps.
b. If connected to relays or other devices, set to match
total electrical power requirements of connected
devices. See device manufacturers’ specifications
and thermostat instructions for details.
Outdoor temperature sensor
In the absence of an external energy management system, an
outdoor temperature sensor must be used.
1. Mount the sensor on an exterior wall, shielded from
direct sunlight or flow of heat or cooling from other
sources.
2. Route sensor wires through a knockout at the rear of the
boiler (see FIG. 5-2).
3. Connect the outdoor temperature sensor (FIG. 5-3) to
the outdoor sensor terminals on the connection board to
enable outdoor reset operation of the outdoor boiler.
High gas pressure switch
If a switch is provided to detect excessive gas pressure, remove
the jumper wire from the terminals on the connection board,
and then connect them to its normally closed contacts (FIG.
5-3).
Low gas pressure switch
1. If a switch is provided to detect low gas pressure, remove the
jumper wire from the terminals on the connection board
and connect them to its normally open contacts (FIG. 5-3).
2. If both a high and low gas pressure switch is used, connect
their respective contacts in series, and connect them to the
terminals on the connection board (FIG. 5-3).
Failure to use the correct sensor may result
in the tank temperature being either above
or below the set point.
WARNING
DHW thermostat
Connect storage indirect water heater (DHW) thermostat
(FIG. 5-3) to the DHW thermostat terminals on the
connection board. If a tank sensor is connected (see DHW
Tank Sensor below) the tank thermostat is ignored.
DHW tank sensor
1. By installing a tank sensor, the SMART SYSTEM control
can perform the tank thermostat function. The SMART
SYSTEM control automatically detects the presence of
this sensor and generates a DHW call for heat when
the tank temperature drops 6°F (3°C) below the tank
set point and finishes the call for heat when the tank
temperature reaches the tank set point.
2. The tank sensor included with the Lochinvar Squire
Indirect DHW tank (TST20015) is the only sensor
suitable for use with the SMART SYSTEM control.
Connect the sensor leads to the Tank Sensor terminals on
the Low Voltage Connection Board (FIG. 5-3).
Variable speed system pump
If a variable speed pump is used in the primary loop, and a
0-10V signal is available from the pump speed control, this
signal can be used by the SMART SYSTEM control to anticipate
changes in the building heat load. By connecting this 0 - 10V
signal to the 0 - 10V SYS PUMP IN terminals, the boiler (or
cascade) can modulate up and down as the primary flow
increases and decreases.
Boiler pump speed output
This 0 - 10V output is available to control the speed of a variable
speed boiler pump. The SMART SYSTEM control will vary the
speed of this pump in order to maintain a minimum
T across
the heat exchanger, as well as prevent high limit lockouts when
the flow in the primary loop is extremely low. Connect this
output to the 0 - 10V input on the boiler pump speed control.
Rate output
This output provides a 0 - 10V signal that is proportional to the
firing rate of the boiler. This may be used by a BMS system to
monitor the actual rate of the boiler.
ModBus
When the optional ModBus interface module is installed, the
RS-485 ModBus cable is connected to these terminals. Use
shielded, 2-wire twisted pair cable. If desired, the shield can
be connected to ground by installing a jumper wire between
terminals 1 and 3 on connector X5 on the optional ModBus
interface module.
3. If the TST20015 is not compatible with the indirect
tank, a tank thermostat can be used to control the
boiler. The tank thermostat should be installed per
the manufacturers instructions and wired to the DHW
Thermostat terminals on the Low Voltage Connection
Board.
Outdoor Knight Boiler Installation & Operation Manual
