Distech Controls ECL-PTU Series - HVAC Mode Management; Temperature Management

42 ECL-PTU-207 Preloaded Applications
HVAC Mode Management
The nvoHeatCool is computed according to nviApplicModeTerminalLoad (nvoFP06)nvoWindowCon-
tact, nviSpaceTemp and FreezepProtSp (nviFP44)
A ChgOverDelay (nviFP44) prevents the nvoHeatCool from switching between cooling and heating too
often.
nviSpaceTemp nvoWindowContact nviApplicMode TerminalLoad
(nvoFP06)
nvoHeatCool
>FreezepProtSp
(nviFP44)
Open Any Any Off
Closed
Auto
>0 Cool mode
<0 Heat mode
=0 Unchanged
Other than Auto Any nviApplicMode
<FreezepProtSp
(nviFP44)
Any Any Any
Heat mode, the fan and
the heating outputs are
overriden to 100%
untilnviSpaceTempreac
hes FreezepProtSp
(nviFP44) +2°C.
Table6: HVAC modes
Temperature Management
Cooling Mode
The cooling or change-over valve is controlled in sequence with the fan speed to maintain the space
temperature to the actual cooling setpoint nvoEffectCoolSp.
The cooling or change-over valve is:
£ rescaled between 0% to 100% when the TerminalLoad (nvoFP06) is between 0% and 100%.
£ disabled when the fan is not running unless the nciFanSettings.FanCtrlType (nviFP39) is set to
None.
£ disabled while in cooling mode if a condensation sensor input is active on DI5 or received from a
master controller.
The fan speed request is rescaled between 0% and CoolMaxFan (nviFP39) when the TerminalLoad
(nvoFP06) is between FanCoolLow and FanCoolHigh.
Heating Mode
The heating or change-over valve is controlled in sequence with the electric heater and the fan speed
to maintain the space temperature to the actual cooling setpoint nvoEffectHeatSp.
£ If the system is not equipped with an electric heater, the heating or change-over valve is rescaled
between 0% and 100% when TerminalLoad (nvoFP06) is between 0% and 100%.
£ If the system is equipped with an electric heater, the heating or change-over valve is rescaled be-
tween 0% to 100% when TerminalLoad (nvoFP06) is between 0% and 50% while the electric
heater is rescaled between 0% to 100% when TerminalLoad (nvoFP06) is between 50% and
100%.
The heating or change-over valve and the electric heater are disabled when the fan is not running un-
less the nciFanSettings.FanCtrlType (nviFP39) is set to None.
The fan speed request is rescaled between 0% and HeatMaxFan (nviFP39) when TerminalLoad
(nvoFP06) is between FanHeatLow and FanHeatHigh.
Sequence of Operation