NuAire ecosmart CONNECT XBOXER XBC, Installation, Control Details, Operating And Maintenance

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7.8.2 ROOM TEMPERATURE CONTROL
Figure 15:
While an enable signal is present, this mode modulates heating, cooling &
heat exchanger bypass dampers with the aim of the room air reaching the
temperature setpoint. Please note that heating and cooling outputs will only
function if the “Heating Type” or “Cooling Type” network inputs are set to
heating or cooling options.
When heating or cooling is required achieve the room setpoint, the output of
the heat/cool loops are split between ventilation demand or heat/cool
demand according to the following graphs. The intermediate “boost” zone is
the area in which a small amount of free-heat/cooling is available. In this zone,
heating/cooling is used to boost the free-heating/cooling.
In room temperature control mode, the bypass damper is controlled according
to the following chart. A minimum supply air temperature limit is included to
stop the heat exchanger being bypassed when the air temp is uncomfortably
cold, even though cooling is required. In this case the heat exchanger will
temper the air for comfort. The reverse applies for the maximum supply air
temperature limit.
If the supply air temperature exits the min-max supply temperature range, the
unit will adjust ventilation, heating or cooling to compensate.
Note: Room temperature control will only be effective if the heater unit is
sized correctly for the space. If the unit is undersized, heating from an
external source may be required.
17 nuaire.co.uk
XBOXER XBC ECOSMART (CO) MODELS
7.0 DESCRIPTION OF CONTROL SOFTWARE STRATEGY
30. 11. 15. Leaflet Number 671710
7.7 CONFIGURABLE MODE (VIA SWITCHED LIVE 2)
The switched live 2 input is a configurable input that can be set to perform a
number of functions. The function is set via the network input Configurable
Mode SL2.
These functions will include the following:
l
Fan Boost (Default Setting)
This enables Fan Boost mode
l
Heater Boost
The heater function will be enabled. Fan speeds will be increased where
necessary to keep supply temp at the heater boost setpoint. (Default 35°C).
7.7.1 FAN BOOST
When the control receives a boost signal, from either the network input
“Boost” or “Configurable SL2” configured to boost the fans will run at boost
speed. Once the signal is removed the fans will run on for a time defined by
the boost run-on setpoint.
7.7.2 HEAT BOOST
When the control receives a heat boost signal, from either the network input
“Heat Boost” or “Configurable SL2” configured to “heat boost”, the heater
output will increase to 100%. The fan speed will be increased as required to
reach the heat boost setpoint.
7.8 TEMPERATURE CONTROL
7.8.1 SUPPLY TEMPERATURE CONTROL (DEFAULT)
Figure 14:
While an enable signal is present, this mode modulates heating, cooling &
heat exchanger bypass dampers with the aim of the supply air reaching the
temperature setpoint. Please note that heating and cooling outputs will only
function if the “Heating Type” or “Cooling Type” network inputs are set to
heating or cooling options.
The heat exchange bypass damper operates by calculating the supply air
temperature based on the return air temperature, the outside air temperature
and the heat exchanger efficiency. (Eg. A 13°C outside air temperature with a
23°C return air temperature will give a supply air temperature of 20.5°C).
The control then chooses the damper position which requires the minimal
heat/cool tempering in order to achieve the setpoint.
Note that the white areas indicate regions where either heat exchanging or
bypassing will achieve the same supply temperature.
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Outside Air Temp
Free Heating
Vent Only
Boost Band
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Heating
Cooling
Boost Band
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Free Cooling
Vent Only
Outside Air Temp
Co
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B
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Bypass
Bypass
HX
HX
Deadband
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Min Supply Outside Max Supply
Air Temp. Air Temp. Air Temp.
Room
Set
Point
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Supply
Set
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Outside Air Temp.
HX
HX
Bypass
Bypass