Despatch RBC1-50 with Protocol Plus - Manual (Page 13)

9
Power Switch
The POWER switch controls power to the control circuit, chamber recirculating fan
motor relay, control cabinet fan, and any options that were included at the time of
purchase.
Air Circulation
A Despatch centrifugal fan draws air through the heater section, moves it evenly across
the chamber, past the temperature sensors and back to the heater. The fresh air is
controlled manually and a modulating damper controls the exhaust.
Chamber Design
The chamber (in which the load is processed) has air supply and exhaust ducts on
opposite sides. The ducts and perforated panels provide uniform airflow and
temperature distribution throughout the chamber.
Airflow Switch
The airflow switch senses the differential pressure between the inlet and outlet side of
the recirculating fan. If there is no air pressure, the switch disconnects power to the
heater, and the alarm horn will signal. An On/Off indicator is visible through a window
on the switch. The switch is located in the upper equipment compartment, behind the
equipment panel and next to the recirculating motor.
Alarm
When there is a high limit condition, or when there is no air pressure sensed by the
airflow switch, an alarm will sound and a red pilot light will be lit. To silence the alarm,
depress the momentary ALARM SILENCE switch. The red light will remain on until the
alarm condition is cleared.