ELECTRICAL CONNECTION
CENTRAL CONTROL CONNECTION & OPERATION – COMMERCIAL MODELS ONLY
PRS-250CN and PRS-250CL commercial
models can be controlled by an external
central control system, such as a time clock or
BMS, which can be programmed to turn the
heater (or group of heater's) ON or OFF at
scheduled times.
The heater will operate in central control mode
when a 24 VAC command signal is received
from the time clock or BMS
A terminal block is located on the rear of the
heater to facilitate this connection as depicted
opposite.
When the 24 VAC central control signal is present, the heater will operate in central control mode and the following
will occur:
•
The 'Central Control LED' on the control panel will illuminate (refer to "Control Panel Overview" diagram on page
8 for LED location).
•
If the control panel cover is locked to prevent control panel operation: The heater will automatically turn ON and
operate according to the heaters current set temperature provided the heater is turned on at the power point and
the heater's
Power
button is on.
•
If the control panel cover is unlocked: The heater will automatically turn ON and operate according to the heaters
current set temperature provided the heater is turned on at the power point and the heater's
Power
button is on.
All functions except set temperature adjustment
(▼ and ▲ buttons),
Economy
button and on/off operation
(
Power
button) will be disabled.
Note:
If a disabled button is pressed whilst the heater is in central control mode,
the 'Central Control LED' will flash.
When not operating in central control mode, the heater can be operated as normal provided access can be gained to
the control panel i.e. the control panel is unlocked.
Notes:
•
The 24 VAC power supply must be supplied from an isolated power supply or isolation type transformer.
•
Minimum command signal wire size for system cable lengths up to 100 metres is 1.5 mm
2
. Command signal
wiring for groups of heaters or for system cable lengths greater than 100 metres must be sized to allow for a
maximum 12% voltage drop and in any case must be not smaller than 1.5 mm
2
.
•
External time clock, BMS and external central control wiring is not supplied with the heater and is to be supplied
and installed by the installing contractor.
•
Commercial models have a
remote
Power
LED and
Filter
LED located on the top of the
heater to facilitate viewing of
these indicators whist the
control panel key lockable
cover is closed/locked.
Controlling a Group of Heaters
The central control system can control a group of two or more heaters by connecting the 24 VAC command signal
wiring in parallel with each heater as depicted below. There is no limit to the number of heaters that can be
connected/controlled in this manner provided the central control system can meet load requirements (5 mA per
heater @ 24 VAC ±25%).
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