26
21. 07. 20. Document Number 671954
Nuaire |
Western Industrial Estate
|
Caerphilly
|
CF83 1NA
|
nuaire.co.uk
XBC+ with Ecosmart Connect (C) Control
Installation Manual
Room Air Tem
p
Supply
Set
Point
Outside Air Temp.
HX
HX
Bypass
Bypass
6.6 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:
•
Fan Boost
(default setting) - Enables Fan Boost Mode
•
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).
•
Extract Setback
- When this SL2 is selected and active, the unit
will force the extract fan to run at a predetermined speed (30%
default), regardless of all other demands. Supply fan will operate at
the normal speed. This mode can be used when the unit is used in
conjunction with a separate air extraction system.
6.6.1 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
their individual boost speeds. Once the signal is removed the fans will
run on for a time defined by the boost run-on setpoint. Any demand in
excess of the boost speed will be ignored (apart from 3 speed override
and purge schedule).
6.6.2 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.
6.7 Temperature Control
6.7.1 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. 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 (e.g. 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.
The white areas indicate regions where either heat exchanging or
bypassing will achieve the same supply temperature.
40
41
42
43
Default HX Operating Conditions
Heating Room Control
Cooling Room Control
Room Set Point HX Operating Conditions
6.7.2 Supply Temperature Control (Default)
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.
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
He
at
Boo
st
Zo
ne
Heating
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.
Room Air Tem
p
Cooling
Boost Band
Free Cooling
Vent Only
Outside Air Temp
Co
ol
Bo
os
t Zo
ne
