V
09/2011
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Operating Instructions
Temperature Control Unit 300L(D)/350L(D)
Operating principle of the two level switches in the
300L(D)
The two level switches in the tank of the 300L(D) each have a specific
switching point. The level switch with the blue marking (S1, NC, upper
switch-point) controls the level control warning lamp and indicates when
the thermal oil must be topped up. The second level switch (S3, NO, lo-
wer switch-point) switches off the feed pump if the oil level is too low, in
order to prevent the pump running dry (see also the Maintenance sec-
tion).
When filling with thermal oil, the feed pump starts up at the lower switch-
point, and the level control warning lamp is switched off at the upper
switch-point.
Rotational field detection / Direction reversal
The rotary field detection of the RT100 control system detects a wrong
phase sequence and reports this in the display or corrects the direction of
rotation automatically.
Venting the Temperature Control Unit
Each time the unit is filled or refilled with thermal oil, the unit and the
temperature control circuit must be vented. To prevent overheating of the
heating elements due to incipient air bubbles in the temperature circuit,
the inlet pressure in the temperature control unit is monitored by a mini-
mum pressure switch. This switch cuts off the heating if the pressure is
too low (0.7 bar) and also activates an alarm. To prevent the heating be-
ing switched on by the control system, a set-point value of approximately
10 °C must be set, and the temperature control unit must be vented at
this value for about 10 minutes.
Re-starting
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Switch on the main switch on the unit
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Open the vent valve on the consumer, and also the shut-off valve
(if fitted)
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Check the temperature control circuit for leaks
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Do not close the vent valve on the consumer until oil is flowing
out of the consumer at a regular rate
WARNING
Risk of burns on touching any parts in contact with the thermal oil!
