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26. 01. 22. Document Number 671829
Nuaire | Western Industrial Estate | Caerphilly | CF83 1NA | nuaire.co.uk
BPS H-AT
Installation Manual
8.0 CONTROLS
The system incorporates a web enabled Trend iQ4E/96/LAN/BAC/230
controller with iQ4/IO/8DO relay expansion module.
36
Trend iQ4E
8.1 Controllable Items
•
Supply fan.
•
Extract fan.
•
Heat recovery bypass damper (If applicable).
•
Thermal wheel (if applicable).
•
Heating coil (if fitted).
•
Cooling coil (if fitted).
•
DX coil (if fitted).
•
Inlet damper (if fitted).
•
Exhaust Damper (if fitted).
•
Recirculation damper (if fitted).
8.2 Enable Signal
The unit can be enabled via the following methods:
•
Software switch (ENABLE) via SDU, IQView4, IQView8 or
network.
•
Switched live (230VAC) input, PIR etc.
•
Extra Low voltage contacts.
•
Night cooling / summer free-cooling strategy.
•
Scheduled via weekly calendar.
When the enable signal is removed, the unit will run on for a time
defined by the run-on setpoint. If an electric heater is fitted, the fans
will automatically run-on for an extra 2 minutes, without heating, in
order to dissipate residual heat.
For DX units the fans will run-on for an extra 5 minutes, this is to allow
for the ramp down of the reverse cycle compressor.
8.3 Occupancy Control
When a Trend occupancy sensor is selected via UI4 & 5 software
module, the control will look for a Trend OCC-U sensor in the
appropriate input. An occupied signal will give an enable signal.
•
0V = Occupied
•
14V = Unoccupied
8.4 Boost Mode
When the control receives a boost signal 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.
8.5 Trickle Mode
When trickle mode is active, the fans will run at their minimum speed
even when there is no enable signal. Heating and cooling will also
function in this mode if available.
8.6 Constant Pressure Sensor
An extract air pressure sensor is fitted as standard. This is disabled in
the Trend strategy by default but can be enabled by the software switch
“Enable Constant Pressure”.
When enabled, the unit will increase the fans speeds as required until
the pressure differential between the extract air and atmosphere
reaches the constant pressure setpoint. The pressure sensor is a 0-10v
0-1000Pa sensor on the iQ4E input 6.
8.7 Filter Differential Pressure Switch
3 filter differential pressure switches are fitted as standard. These
monitor the Extract filter, and Supply filter and Supply pre-filters.
These are connected in series with Alarm Circuit 2 (orange wires) and
will break the circuit on overpressure. The adjustable range is 0.5 to 4
mbar and is set by default to 2mbar.
8.8 Thermal Wheel / Plate Heat Exchanger Bypass
The plate heat exchanger bypass damper and thermal wheel both run
on the same iQ4-8DO Relay 1. Energised = Bypass.
The bypass strategy is as follows: If the fresh air temperature is equal
to the setpoint within the deadband, then the heat exchanger will be
forced into bypass mode.
The 24vac bypass signal from the Trend relay is converted by relay logic
for each of the following options:
•
Thermal Wheel
Runs on a volt free enable signal, which is produced using a
combination of the HX bypass relay and fan run relay to close the
circuit if fans are running and the unit is not in bypass.
•
Plate Heat Exchanger
The HX bypass damper opens on a 24 Vac signal which is produce
from the bypass damper relay.
8.9 Inlet / Outlet (IO) Dampers
Inlet and outlet dampers are 24vac and controlled by the iQ4-8DO
relay 7. When energised it gives a 24vac signal to both I/O dampers to
open.
When installed, there is the option of connecting the internal damper
close switch to the fault circuit alarm circuit 2 (orange wires).
When IO dampers are fitted the strategy Switch “IO Damper Fitted”
must be set to “On”. This will cause the software to delay the fans
starting for the IO Damper delay period. It will also ignore faults on
Alarm Circuit 2 if the fans are stopped and the dampers are closed
intentionally.
8.10 CO
2
Control
When a CO2 sensor is selected via UI4 & 5 function knobs, and an
enable signal is received, ventilation will increase to reduce CO2
concentration the target CO2 setpoint. The target CO2 sensor setpoint
can be changed as one of the commissioning setpoints.
