SEELEY INTERNATIONAL DU User manual

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Aira Control Configuration Options
DU/SD/HCV and HCVR

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Contents
Introduction.............................................................................................................................................................. - 3 -
Control box Design. .................................................................................................................................................. - 3 -
Unit Identification..................................................................................................................................................... - 3 -
All Units Main Isolator .............................................................................................................................................. - 3 -
Control box labelling................................................................................................................................................. - 3 -
Units Operated by BMS ............................................................................................................................................ - 4 -
SD/DU Heater without Blower ............................................................................................................................. - 4 -
SD/DU Heater with Blower................................................................................................................................... - 4 -
SD/DU Heater VSD ............................................................................................................................................... - 4 -
Control Signals BMS All ........................................................................................................................................ - 4 -
DU/SD Fan only .................................................................................................................................................... - 4 -
Heating Cooling Ventilation (HCV) Units.............................................................................................................. - 5 -
HEAT ON........................................................................................................................................................... - 5 -
COOL ON .......................................................................................................................................................... - 5 -
VENTILATION ONLY.......................................................................................................................................... - 5 -
HCV VSD ............................................................................................................................................................... - 5 -
HEAT ON........................................................................................................................................................... - 5 -
COOL ON .......................................................................................................................................................... - 5 -
Heating Cooling Ventilation Return Air (HCVR).................................................................................................... - 5 -
Dual Heat exchanger ............................................................................................................................................ - 5 -
3rd Party External Cooler Attachment Heater Only .............................................................................................. - 6 -
Rotary Switch............................................................................................................................................................ - 6 -
Dual Heat exchanger ............................................................................................................................................ - 6 -
Heating Cooling Ventilation Return Air (HCVR).................................................................................................... - 7 -
Wall Switch ............................................................................................................................................................... - 7 -
DU/SD Heater with Blower SINGLE heat exchanger ............................................................................................ - 7 -
DU/SD Heater without Blower SINGLE heat exchanger....................................................................................... - 7 -
3rd Party External Cooler Attachment.............................................................................................................. - 7 -
HCV and HCVR SINGLE heat exchanger................................................................................................................ - 8 -
DU/SD Heater with Blower DUAL heat exchanger ............................................................................................... - 8 -
DU/SD Heater without Blower DUAL heat exchanger ......................................................................................... - 8 -
HCV and HCVR DUAL heat exchanger .................................................................................................................. - 9 -
Climate Wizard Connection ...................................................................................................................................... - 9 -
Summary................................................................................................................................................................... - 9 -

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Introduction.
This document is design to describe the wiring requirements for the Aira universal control box CH637
and needs to be used in conjunction with the Aira wiring diagram package. ONLY an authorised
electrician should attempt to make any connections with the universal control box.
Control box Design.
The Aira Control box is a universal fit which covers all models of HCV, HCVR, DU and SD heaters and Dual
heat exchanger variants. There are multiple control configurations which can be used, including Building
Management System (BMS), Rotary wall switch, and Wall switch. In order to access the different control
options, different control box connections must be made to suit the installation type. For an installation
type which is not listed within this document please contact a Seeley International representative for
assistance.
Unit Identification
First step is to determine the unit configuration DU, SD, HCV or HCVR. All units using this control box use
either a DU or SD heater which are identical except for the heat exchanger height. The heat exchanger
height does not affect the wiring of the unit so DU and SD heater can be treated as the same unit.
DU/SD units can have either a blower attached or a remote blower (Customer supplied) further back in
the ductwork. If the unit has a blower attached it is known as a DU with blower or SD with blower. If it
has a remote blower the unit is supplied as a DU without blower or SD without Blower.
HCV and HCVR units are easily identified by the blower section also containing evaporative cooling pads.
And are essentially a DU/SD heater and an evaporative cooler adjoined.
Dual heat exchanger models can be variants of any of the units described above. They are identified by
1. Clear division in the heat exchanger 2. Dual control boxes (Master and Slave) and 3. Dual Gas inlets
All Units Main Isolator
All control boxes will require 1Phase 240V power supply. Depending on the model requirements the
Main Isolator will need to be supplied with either 1 Phase 240V or 3 Phase 415V, Please refer to Model
Specifications and Rating Plate
NOTE: The drawing package contains the full wiring diagram for the Aira universal control box and is
supplied for fault finding only. No attempt should be made to alter/bypass the wiring within the control
box except where specified in this document. A Seeley International representative must be contacted if
there is a perceived fault present.
Control box labelling
The control box is labeled to help identify the control terminals need. The terminal strips have a ‘X’
identifier and the individual terminals a unique number within the corresponding terminal block i.e.
X1/43 is Terminal number 43 within Terminal block X1. The terminal blocks are numbered within the
control box but can also be identified by using the drawings. Terminal Block locations see Drawing 002
for Master box and 003 for Slave box.

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Units Operated by BMS
BMS have the ability to control the systems within the unit but should not be used to bypass
fundamental safety controls.
SD/DU Heater without Blower
DU/SD heater without blower will require a blower to supply air to the unit. This is generally in the form
of an evaporative cooler in ventilation mode or an independent blower installed upstream of the heater,
which is customer supplied. The DU/SD heater uses an Auto Fan Switch (AFS) which must be operated in
order for the heater to function. This is links in with the temperature sensors and forms part of the
heaters safety system, this must not be bridged or bypassed. In addition the AFS / Fan Low signal must
be incorporated into the fan control circuit to prevent overheating of the heat exchanger at the end of
the heating cycle. The AFS is a thermostat that detects when the heat exchanger is hot and operates the
fan to provide air flow over the heat exchanger until the temperature lowers to the set condition.
In order to operate the AFS a 24V signal must be connected from fan low relay (X4/61, X4/62) to the
AFS. All BMS setups are expected to be a dry contact.
See wiring diagram No.007 for full connection details.
SD/DU Heater with Blower
DU/SD heater with blower have a fan/blower factory fitted to the rear of the DU/SD heater and will
have the fan motor starter box prewired to the control box. To operate the heater start signals to heat
signal and fan low. (X4/61, X4/62) are required.
All BMS setups are expected to be a dry contact. See wiring diagram No. 007 for full connection details.
SD/DU Heater VSD
There are several different ways a Variable speed drive can be setup to operate with the unit. The most
typical installation is to setup the VSD to operate when low fan relay is switched on. A signal to the Auto
Fan Switch (AFS) from fan low relay signal out to fan motor control (X4/61, X4/62) is required.
See wiring diagram No. 007 for full connection details.
Control Signals BMS All
Common control signals when using a BMS, Low fan X3/41, Heat X3/44, BMS common terminal X3/46
See wiring diagram No.007 for full connection details.
DU/SD Fan only
To operate the fan only for ventilation provide a signal to X3/41
See wiring diagram No.007 for full connection details.

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Heating Cooling Ventilation (HCV) Units
HCV units being an integrated gas heater and evaporative cooler, which can operate in three modes.
Heating Cooling and Ventilation.
To operate each mode the following signal connections are needed.
HEAT ON
•Signal in for fan low on X3/41
•Signal in for Heat X3/44
COOL ON
•BMS connect to X3/43 Pump only
•Low fan on X3/41
•High Fan X3/42
VENTILATION ONLY
•Signal in Low fan on X3/41
•Signal in High Fan X3/42
See wiring diagram No. 007 for full connection details.
HCV VSD
A unit specified for supply with a VSD will not have a motor starter box installed from factory. The VSD
will need to have high fan and low fan speeds preset which will be used for heating and cooling alike.
These will need to connect to the corresponding relays.
Need to take a signal to the Auto Fan Switch (AFS) from fan Low relay (X4/61, X4/62).
HEAT ON
•Signal in for fan low on X3/41
•Signal in for Heat X3/44
COOL ON
•BMS connect to X3/43 Pump only
•Low fan on X3/41
•High Fan X3/42
In order to operate the AFS a 24V signal must be connected from fan Low relay (X4/61, X4/62) to the
AFS. All BMS setups are expected to be a dry contact. See wiring diagram No.007 and No.011 for full
connection details.
Heating Cooling Ventilation Return Air (HCVR)
Heat ON will close fresh air dampers and open return air. Once Heat is switched off dampers will
automatically return to cooling position as default. All the connection for HCV are applicable for the
HCVR. Refer to HCR section of this document for connections.
Dual Heat exchanger
Dual heat exchanger models have a master and slave control box which are looped together. The BMS
must supply a 0-10V signal for the room temperature and set point temperatures.

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3rd Party External Cooler Attachment Heater Only
The fan function within the 3rd party cooler will need to be used to trigger the Low fan signal on X3/41.
Be aware the temperature rise of the heater is affected by the airflow. Seeley cannot guarantee the
correct temperature rise of the heater with the use of 3rd party supply air.
Rotary Switch
Rotary switch control is only Applicable for HCV and HCVR, therefore not applicable for SD/DU Heater
with or without Blower.
•Switch requires 24V supply from X4/65, X4/66.
•Connect Fan Low switch to X3/41
•Connect Fan High switch to X3/42
•Connect Heat Switch to X3/44
•Connect reset switch to X3/45 needs 24V from X4/65 which can be looped in plate.
•Connect Remote lockout light to X3/50 and bridge X3/49 to X4/65 and connect light to 0 volts,
X4/66
•Room Thermostat QAA25 B or T2 wires to X3/51, and M or T1 wire to X3/52 and R or T3 wires to
X3/53
See wiring diagram No. 004 for full connection details.
Dual Heat exchanger
Dual heat exchanger models have a master and slave control box. Each control box has a PLC with which
requires a thermostat input. In order to use a single room thermostat the following connection must be
made.
•Pickup 24V supply from X4/65, X4/66
•Connect Low Fan switch to X3/41
•Connect Heat Switch to X3/44
•Connect Reset switch to X3/45 also need 24V can pick up from X4/65 can be looped in wall
plate.
•Remote lockout light X3/50 and X3/49 bridges to X4/65 and X4/66 wires to 0 volts for light
•Room Thermostat Separate QAA2061 – G wires to X4/65 and U1 wires to X3/51 and G0 wires to
X4/66
•Setpoint Thermostat RLA162 – G wires to X4/65 and Y1 wires to X3/53 and G0 wires to X4/66 –
Set dipswitch 4 to ON. 0 to 10V output is set by temp dial.
•RLU settings – X2 0 to 10 V min 0 max 50Deg C and X3 0to10V min 8 max 30Deg C
See wiring diagram No. 008 for full connection details.

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Heating Cooling Ventilation Return Air (HCVR)
Heat ON will close fresh air dampers and open return air. Once Heat is switched off dampers will
automatically return to cooling position as default. All the connection for HCV are applicable for the
HCVR. Refer to HCR section of this document for connections.
Wall Switch
The wall switch plate control can be found on either DU/SD heaters or HCV/HCVR units. And either
single or dual burner heat exchanger models. The correct process is unit type dependent.
DU/SD Heater with Blower SINGLE heat exchanger
DU/SD heater with blower has a fan/blower factory fitted to the rear of the DU/SD heater and will have
the fan motor starter box prewired to the control box. To operate the heater start signals to heat signal
and fan low. (X4/61, X4/62) are required.
The following terminals need to be connected for supplied wall switch control
•Connect Low Fan switch to X3/41
•Connect Heat Switch to X3/44
•Connect Reset switch to X3/45 also need 24V can pick up from X4/65 can be looped in plate.
•Remote lockout light X3/50 and X3/49 bridges to X4/65 and X4/66 wires to 0 volts for light
•Common X3/46 bridge to X4/66
•Room Thermostat QAA25; B or T2 wires to X3/51, and M or T1 wire to X3/52 and R or T3 wires
to X3/53
See wiring diagram No. 006 for full connection details.
DU/SD Heater without Blower SINGLE heat exchanger
DU/SD heater without blower will require a blower/fan to supply air to the unit. This is generally in the
form of an evaporative cooler in ventilation mode or an independent blower installed upstream of the
heater, which is customer supplied. The DU/SD heater uses an Auto Fan Switch (AFS) which must be
operated in order for the heater to function. This is links in with the temperature sensors and forms part
of the heaters safety system, this must not be bridged or bypassed.
3rd Party External Cooler Attachment
Use supplied HCV wall switch to operate the heater and the cooler. This will ensure that the low speed
setting on the cooler can be used with the heater. The Cooler must have a 2 speed motor fitted and the
pulley ratio set to match the required temperature rise of the heater.
Where the coolers operation is more complex than the wall switch is designed to manage, an additional
3rd party controller may be required. which is not covered within this document. For assistance please
contact a Seeley International representative.
See wiring diagram No. 005 for full connection details.

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HCV and HCVR SINGLE heat exchanger
HCV units are intended to operate in Heating with Low speed fan operating and cooling with high speed
fan and water pump. The will switch needs to be connected in the following way to operate all
functions.
•Connect Low Fan switch to X3/41
•Connect High Fan switch to X3/42
•Connect Heat Switch to X3/44
•Connect Cool Switch to X3/43
•Connect Reset switch to X3/45 also need 24V can pick up from X4/65 can be looped in plate.
•Remote lockout light X3/50 and X3/49 bridges to X4/65 and X4/66 wires to 0 volts for light
•Common X3/46 bridge to X4/66
•Room Thermostat QAA25; B or T2 wires to X3/51, and M or T1 wire to X3/52 and R or T3 wires
to X3/53
See wiring diagram No. 005 for full connection details.
DU/SD Heater with Blower DUAL heat exchanger
DU/SD heater with blower has a fan/blower factory fitted to the rear of the DU/SD heater and will have
the fan motor starter box prewired to the control box. To operate the heater start signals to heat signal
and fan low are required.
Dual heat exchanger models have a master and slave control box. Each control box has a PLC with which
requires a thermostat input. In order to use a single room thermostat the following connection must be
made.
•Pickup 24V supply from X4/65, X4/66
•Connect Low Fan switch to X3/41
•Connect Heat Switch to X3/44
•Connect Reset switch to X3/45 also need 24V can pick up from X4/65 can be looped in wall
plate.
•Remote lockout light X3/50 and X3/49 bridges to X4/65 and X4/66 wires to 0 volts for light
•Room Thermostat Separate QAA2061 – G wires to X4/65 and U1 wires to X3/51 and G0 wires to
X4/66
•Setpoint Thermostat RLA162 – G wires to X4/65 and Y1 wires to X3/53 and G0 wires to X4/66 –
Set dipswitch 4 to ON. 0 to 10V output is set by temp dial.
•RLU settings – X2 0 to 10 V min 0 max 50Deg C and X3 0to10V min 8 max 30Deg C
See wiring diagram No. 010 for full connection details.
DU/SD Heater without Blower DUAL heat exchanger
DU/SD heater without blower will require a blower/fan to supply air to the unit. This is generally in the
form of an evaporative cooler in ventilation mode or an independent blower installed upstream of the
heater, which is customer supplied. The DU/SD heater uses an Auto Fan Switch (AFS) which must be
operated in order for the heater to function. This is links in with the temperature sensors and forms part
of the heaters safety system, this must not be bridged or bypassed.

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Dual heat exchanger models have a master and slave control box. Each control box has a PLC with which
requires a thermostat input. In order to use a single room thermostat the following connection must be
made.
•Pickup 24V supply from X4/65, X4/66
•Connect Low Fan switch to X3/41
•Connect Heat Switch to X3/44
•Connect Reset switch to X3/45 also need 24V can pick up from X4/65 can be looped in wall
plate.
•Remote lockout light X3/50 and X3/49 bridges to X4/65 and X4/66 wires to 0 volts for light
•Room Thermostat Separate QAA2061 – G wires to X4/65 and U1 wires to X3/51 and G0 wires to
X4/66
•Setpoint Thermostat RLA162 – G wires to X4/65 and Y1 wires to X3/53 and G0 wires to X4/66 –
Set dipswitch 4 to ON. 0 to 10V output is set by temp dial.
•RLU settings – X2 0 to 10 V min 0 max 50Deg C and X3 0to10V min 8 max 30Deg C
HCV and HCVR DUAL heat exchanger
Dual heat exchanger models have a master and slave control box. Each control box has a PLC with which
requires a thermostat input. In order to use a single room thermostat the following connection must be
made.
•Pickup 24V supply from X4/65, X4/66
•Connect High Fan switch to X3/42
•Connect Low Fan switch to X3/41
•Connect Heat Switch to X3/44
•Connect Cool Switch to X3/43
•Connect Reset switch to X3/45 also need 24V can pick up from X4/65 can be looped in wall
plate.
•Remote lockout light X3/50 and X3/49 bridges to X4/65 and X4/66 wires to 0 volts for light
•Room Thermostat Separate QAA2061 – G wires to X4/65 and U1 wires to X3/51 and G0 wires to
X4/66
•Setpoint Thermostat RLA162 – G wires to X4/65 and Y1 wires to X3/53 and G0 wires to X4/66 –
Set dipswitch 4 to ON. 0 to 10V output is set by temp dial.
•RLU settings – X2 0 to 10 V min 0 max 50Deg C and X3 0to10V min 8 max 30Deg C
See wiring diagram No. 009 for full connection details.
Climate Wizard Connection
To connect an Aira DU/SD heater in line with a Seeley International Climate Wizard please contact a
Seeley International representative.
Summary
This document is details for the installation of standard option configurations. For any installation which
is not listed her. Please contact a Seeley International representative.