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15. 02. 22. Document Number 672040
Nuaire | Western Industrial Estate | Caerphilly | CF83 1NA | nuaire.co.uk
BPS H-CO
Installation Manual
1.12 Temperature Control
1.12.1 Supply Temperature Control (Default)
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. 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 (e.g. 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.
2
Supply Temperature Control - HX Bypass
Room Air Tem p
Supply
Set
Point
Outside Air Temp.
HX
HX
Bypass
Bypass
White areas indicate regions where either heat exchanging or
bypassing will achieve the same supply temperature.
1.12.2 Room Temperature Control
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 heating/
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 minimum - maximum supply
temperature range, the unit will adjust ventilation, heating or cooling to
compensate.
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.
Room Air Tem p
Outside Air Temp
Free Heating
Vent Only
Boost Band
H
e
at B
oost
Zone
Heating
3
Room Temperature Control - Heating
Room Air Tem p
Cooling
Boost Band
Free Cooling
Vent Only
Outside Air Temp
Cool Boost
Zone
4
Room Temperature Control - Cooling
Bypass
Bypass
HX
HX
Deadband
Room Air Tem p
Min Supply O utside Max Supply
Air Temp. Air Temp. Air Temp.
Room
Set
Point
Outside
Air Temp.
5
Room Temperature Control - HX Bypass
1.12.3 Overrides
When the following conditions occur, the system will temporarily exit
“Room Temperature Mode” and enter “Supply Temperature Mode”.
•Trickle Mode with no enable signal (Trickle deadband applies).
•Heat Boost Active
•Fan Boost Active
•Purge Mode Active
•3-Speed override by Room Module
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