44
Enertech Global
IOM, BS/BT Models
20D2
39−
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INITIAL RELEAS
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Section 9: Controls
Settings
Lockout Board DIP Switches The lockout board
has four DIP switches for field selection of features
shown below.
Load/Source Temperature Sensing (FSW)
When the DIP switch FSW is OFF, the board
operates in Load and Source Heat Exchanger
Temperature Sensing Mode (LCT and SCT
monitored, FS terminals ignored), which is the
factory setting. When the DIP switch FSW is ON,
the board monitors flow switch.
Anti-Freeze (AFRZ)
When DIP switch AFRZ is OFF, the Lockout Board
operates in open loop mode. The setpoint for the
source heat exchanger freeze sensor is set to 30°F.
When DIP switch AFRZ is ON, the board operates
in the closed loop mode. The setpoint for the source
heat exchanger freeze sensor is 15°F in closed loop
mode.
Test Mode (TEST)
When DIP switch TEST is OFF, the Lockout board
operates in the normal mode. When DIP switch
TEST is ON, the board operates in test mode, which
speeds up all delays for easier troubleshooting.
While in the test mode
the LCT & SCT sensors will be checked for the
proper location based on temperature. Sensors
are swapped if LCT > SCT in cooling or LCT < SCT
in heating. This fault will only show up in the test
mode. When service is complete, the DIP switch
TEST must be returned to the OFF position in
order to make sure the unit operates with normal
sequencing delays. While the unit is in Test Mode,
the status light (bottom green) will remain off. The
Lockout Board will revert back to normal mode
after one (1) hour (green status light blinks), if DIP
switch TEST is not moved to OFF position.
Over/Under Voltage Disable (O/U)
When the DIP switch O/U is ON, the over/under
voltage feature is active. When the DIP switch
O/U is OFF, the over/under voltage feature is
disabled. On rare occasions, variations in voltage
will be outside the range of the over/under voltage
feature, which may require to disabling of the
feature. However, disabling the feature could
cause the unit to run under adverse conditions,
and therefore should not be turned off without
contacting Enertech technical services. An over/
under voltage condition could cause premature
component failure or damage to the unit controls.
Any condition causing this fault must be thoroughly
investigated before taking any action regarding
disabling O/U feature. Likely causes of an over/
under voltage condition include power company
transformer selection, insufficient entrance wire
sizing, defective breaker panel, incorrect 24VAC
transformer tap (unit control box), or other power-
related issues like brownouts.
DIP Switch 1-4
OFF
ON
1-FSW: Temp Sensor Mode
Monitor LCT & SCT Inputs
Flow Switch Mode:
Monitor Flow Switch
2-AFRZ: Open Loop Operation
SCT=30°F
Closed Loop Operation:
SCT=15°F
3-Test: Normal Mode
Green Status LED=Blink
Test Mode:
Green Status LED=OFF
Timers are divided by 60
4-O/U: Over/Under Voltage
Protection Disabled/Off
Over/Under Voltage
Protection
Enabled/ON