Enertech VS Series - Heating and Cooling Stages

43
IOM, VS/VT Models, Rev A Enertech Global
Section 9: Controls
Heating 3rd Stage, (Y1, Y2, W1, G) VT Units or
Heating 2nd Stage (Y1, W1, G) VS Units
When provided, the ECM fan remains at 100% of
2nd stage airow (CFM) level (based on DIP switch
settings), and the rst stage of electric resistance
heat is energized. Second stage of electric
resistance heat (W2) is energized ten minutes after
rst stage electric resistance heat (W1) is energized.
(W2 is only available with 10kW, 15kW and 20 kW
electric heaters)
Emergency Heat (W1, G) VT or VS Units
The fan is started immediately at 2nd stage airow
(CFM) level (based on DIP switch settings), and the
electric resistance heat is energized. Second stage
of electric heat (W2) is energized two minutes after
rst stage electric heat (W1) is energized. (W2 is
only available with 10kW, 15kW, and 20 kW electric
heaters)
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) VT or VS Units
The ECM fan immediately ramps up to 75% of 1st
stage (VT) or 2nd stage (VS) airow (CFM) level
(based on DIP switch settings), the Accessory (A)
terminal output is energized after the random start
timer (10s-20s) expires then rst stage compressor
and the loop pump(s) are energized 10 seconds
after “A”. The ECM fan adjusts to 100% airow
(CFM) level 90 seconds after the “Y1” input. VS units
with a PSC fan start at 100% airow (CFM) level
immediately upon the “G” input.
Cooling 2nd Stage (Y1, Y2, O, G) VT Units Only
The ECM fan adjusts to 2nd stage airow (CFM) level
(based on DIP switch settings), and the compressor
full load solenoid is energized.
Cooling, Dehumidication Mode VT or VS Units
When provided with an ECM fan motor, the
ECM fan control board includes two types of
dehumidication modes, Constant Dehumidication
mode, and On Demand Dehumidication (ODD).
If the ECM control board is set to Constant
Dehumidication mode, the ECM fan runs at normal
airow (CFM) in all heating stages, but all cooling
operation will be 85% of the current stage airow
(CFM) level (based on DIP switch settings). The
dehumidication mode lowers the airow (CFM)
through the evaporator coil, to improve latent
(dehumidication) capacity.
In ODD mode, a humidistat or a thermostat with a
dehumidication 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 dehumidication, the fan runs at
85% of the current stage airow (CFM) in the cooling
mode. Otherwise, the airow is at the normal airow
(CFM) level. The signal is ignored in the heating
mode.
Fan Only VT or VS Units
When the ECM control module receives a “G”
call without a call for heating or cooling, the fan
operates at 50% of the full load airow (CFM) level
(based on DIP switch SETTINGS). VS units with a PSC
fan start at 100% airow (CFM) level immediately
upon the “G” input.
Dehumidication Mode Options
(ECM Fans Only)
DIP Switch
Mode Operation
S9 S10
ON OFF Normal
Dehumidication mode
disabled (normal Htg/Clg
CFM) - factory setting
OFF ON ODD
On Demand Dehumidication
mode (humidistat input at
terminal ODD) -
Humidistat required
OFF OFF
Constant
Dehum
Constant dehumidication
mode (always uses dehum
CFM for cooling and normal
CFM for heating) -
No humidistat required
ON ON Not Used Not an applicable selection
Notes:
1. To enter dehumidication mode, ODD input should be
0 VAC; for normal cooling CFM, ODD input should be
24VAC.
2. Heating CFM is not affected by dehumidication mode.
When in dehumidication mode, cooling CFM is 85% of
normal cooling CFM.