40
Enertech Global
IOM, XT Models
Section 9: Controls
Figure 14: Lockout Board Layout
A
C
R
Y
L
O
CCG
CC
HP
HP
LP
LP
FS
FS
CO
CO
Lockout
Board
Status
R2 R1 C2 C1
WSD
TEST
O/V
Sequence of Operation
Water-to-Air Units, Single Compressor, ECM Fan
Heating, 1st Stage (Y1,G) Two-Stage Units
The ECM fan is started immediately at 75% (of 1st
stage operation) CFM level (based on DIP switch
settings), first stage compressor and the loop/
desuperheater pump(s) are energized 10 seconds
after the “Y1” input is received, and the ECM fan
adjusts to 100% (of 1st stage operation) CFM level 30
seconds after the “Y1” input.
Heating, 2nd Stage (Y1,Y2,G) Two-Stage Units
The ECM fan adjusts to 2nd stage CFM level (based
on DIP switch settings), and the compressor full load
solenoid valve is energized.
Heat, 3rd Stage (Y1,Y2,W,G) Two-Stage Units
The ECM fan remains at 100% of 2nd stage CFM
level (based on DIP switch settings), and the electric
backup heat is energized.
Emergency Heat (W,G)
The fan is started immediately at 2nd stage CFM
level (based on DIP switch settings), and the electric
backup heat is energized.
Cooling Operation
The reversing valve is energized for cooling
operation. Terminal “O” from the thermostat is
connected to the reversing valve solenoid.
Cooling, 1st stage (Y1,0,G) Two-Stage Units
The ECM fan is started immediately at 75% (of 1st
stage operation) CFM level (based on DIP switch
settings), first stage compressor and the loop/
desuperheater pump(s) are energized 10 seconds
after the “Y1” input is received, and the ECM fan
adjusts to 100% (of 1st stage operation) CFM level 30
seconds after the “Y1” input.
Cooling, 2nd Stage (Y1,Y2,O,G) Two-Stage Units
The ECM fan adjusts to 2nd stage CFM level (based
on DIP switch settings), and the compressor full load
solenoid valve is energized.
Cooling, Dehumidification Mode
The ECM control module includes two types of
dehumidification modes, Forced Dehumidification
mode, and On Demand Dehumidification (ODD). If
the ECM control
module is set to Forced Dehumidification mode, the
ECM fan runs at normal CFM in all heating stages,
but all cooling operation will be 85% of the current
stage CFM level (based on DIP switch settings),
which lowers the CFM through the evaporator
coil, improving latent capacity. In ODD mode, a
humidistat or a thermostat with a dehumidification
output (output must be reverse logic -- i.e. it must
operate like a humidistat) is connected to the
ODD terminal. When the module receives a call
for dehumidification, the fan runs at 85% of the
current stage CFM in the cooling mode. Otherwise,
the airflow is at the normal CFM level. The signal is
ignored in the heating mode.
Fan Only
When the ECM control module receives a “G”
call without a call for heating or cooling, the fan
operates at a lower CFM level (based on DIP switch
settings).