Monmouth Scientific PCR650, Operating And Maintenance Manual

Page: 9 / 12

9
SECTION 5
MAINTENANCE
The cabinet should be isolated from the electricity supply before carrying
out any maintenance procedures.
FUSES
Always replace fuses with the correct type and rating:
The main fuses (5A Type T) are located in the mains inlet socket at the back of
the cabinet. Remove the mains lead and withdraw the fuses using a small
screwdriver.
The fan fuse (3.15A Type T) is located on the control circuit board and may be
changed by removing the two securing screws from inside the cabinet and
hinging the control panel open.
LIGHTING
The fluorescent light tube can be accessed from inside the cabinet. The starter
is located inside the control panel and may be changed by removing the two
securing screws from inside the cabinet and hinging the control panel open.
The fluorescent light fuse (2A Type F) is located on the control circuit board.
UV TUBE
The UV tube can be accessed from inside the cabinet. The starter is located
inside the control panel and may be changed by removing the two securing
screws from inside the cabinet and hinging the control panel open. The UV
light fuse (2A Type F) is located on the control circuit board.
AIRFLOW
WARNING: This procedure requires adjustment of live circuits and should only
be carried out by a qualified person.
The airflow should be set using a calibrated rotating vane anemometer. The
fan speed is adjusted by turning the blue potentiometer on the speed control
circuit board inside the control panel. The speed should be set to achieve a
downflow of 0.3 – 0.35m/sec. at 100mm above the lower edge of the front fixed
glazing panel.
LOW AIRFLOW ALARM
1. Set the airflow to the correct speed with new pre-filters fitted.
2. Switch the cabinet on and place a piece of paper or similar material against
the pre-filter inlet grille covering all but 14 of the 84 holes to simulate a
partially blocked filter.
3. Unscrew the pressure switch adjusting screw until the low airflow warning
LED comes on. Screw in until the LED goes out then slowly unscrew until
the LED comes on again.
4. Remove and replace the paper several times to check operation of warning
LED / audio.