SECTION 9: WIRING AND ELECTRICAL INFORMATION
SECTION 9: WIRING AND ELECTRICAL INFORMATION
9.1 Electrical Supply
A 230 V 50 Hz 1 Ø supply is required for all heater Models 015 to 030 connected to the heater terminals L1, N and Earth.
Standard models 040 to 0100 and all High Flow models require a 400 V 50 Hz 3 Ø and neutral supply connected to the heater terminals L1, L2, L3, N and Earth.
All heaters and controls must be correctly earthed. All external wiring must comply with the relevant IEE and local regulations and be carried out by a qualified electrician.
It is important that "L and N" polarity is correct for these heaters, as incorrect polarity may prevent the burner control box from operating properly. It is also important that the voltage between N and earth is at 0 V and can never exceed 15 V.
An isolator with a contact separation of at least 3
mmon all poles should be installed adjacent to the heater, but not attached to it, to disconnect all supplies to the heater and where necessary to isolate the remote control panel.
The final connection to the heater should be made in metal sleeved flexible cable or flexible conduit to the main terminal block under the front lower panel of the heater using 1 sq. mm cable. Model 0100 and High Flow models with 5.5kW or 7.5kW motors use
1.5sq. mm cable. Cable entry is provided into the rear horizontal frame of the cabinet.
WARNING
Electrical Shock Hazard
Disconnect electrical power before servicing.
Failure to follow these instructions can result in death or electrical shock.
9.2 Remote Controls
The heater is designed to be operated by controls installed remotely from the heater. See Page 20, Section 9.3. through Page 27, Section 9.10.
9.2.1 Burner Controls (Thermostat)
Controls to operate the burner must be voltage free contacts connected between terminals 2 & 3 of the main terminal block.
9.2.2Positioning Room Thermostats or Roberts-Gordon Control
Aroom thermostat or
9.2.3 Remote Frost Thermostat
When required, connect to terminals 2 and 3 in the main terminal block.
Locate the thermostat within the heated space adjacent to the most vulnerable equipment that requires protection.
See Page 20, Section 9.3 through Page 27, Section 9.10.
9.2.4 Controls for High/Low Burner Operation
For heaters with a high/low burner, the controls will need to provide two stage signal to operate these burners. This is best provided by a two stage thermostat.
The thermostat may control the heater outlet temperature if the heater is designed for a duct distribution system or the room temperature.
The site wiring will be across terminals 2 and 3 for any time control and the on/off function of the burner (stage two), and across terminals 7 and 8 for the high fire (first stage) setting.
The burner will then operate as follows:
Temp. from cold up to |
|
the 1st set point | Full fire at max. rate |
Temp. above 1st set point |
|
up to 2nd set point | Low fire at min. rate |
Temp. above 2nd set point | Off. |
9.2.5 Controls for Fully Modulating Burners
For heaters that incorporate a fully modulating burner, a special temperature control is provided with the heater.
The heater will normally be controlled by the temperature of the air in the outlet duct, but it is possible to control on room temperature.
The position of the sensor in the outlet duct is determined on site. Using a themometer, select a position in the outlet duct approximately 1 m from the heater, across the cross section of the duct that provides a reasonable average of the temperatures found. Mount the sensor at this position for best results.
When operating at reduced heat input, the leaving air temperature may be low when controlled on room temperature.
The time control and any other on/off controls will be across terminals 2 and 3. The sensor will be connected to terminals 8 and 9.
The operation will occur in the following sequence:
1.The burner will fire. When the burner sequence reaches the release to modulation stage, the control will begin to monitor the outlet temperature.
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