This section applies only to units supplied with refrigeration.
When the unit power is on, refrigeration will be initiated automatically
based on the set point. The main power switch needs to be ON for the
refrigeration system to work. When the refrigeration system is activated,
the compressor system will run continuously and the system will go
through the following routine:
Upon every automatic activation of the refrigeration system, there is an
approximate 2 minute delay until the compressor becomes activated. This
is a safety feature, to prevent damage to the compressor. Because the
compressor does not turn on immediately after the automatic activation of
the refrigeration system, please note, THIS IS NORMAL. The defrost
timer will begin initiation. This may turn the fans off for several minutes
until it completes a normal defrost cycle.
During operation, the defrost timer will automatically “engage” every 12
hours for a duration of 30 seconds (factory default setting). The defrost
cycle switches cold gas through the evaporator (inside) coils to hot gas in
order to defrost the coils. The defrost settings may require adjustment,
depending on environmental conditions, to eliminate frost build-up on the
coils.
Refrigerated MaxQ 6000 units incorporate a defrost cycle to alleviate
issues associated with the build-up of condensation (ice) on the evaporator
coil which is visible inside the chamber. It may be desirable to alter or
disable this cycle based on user conditions. Default mode is 12 hours
between cycles and 30 seconds of defrosting the evaporator coil with 15
seconds before the chamber blower comes on. The display will flash “dEF”
while in defrost mode.
1. If the unit is powered up, press the POWER key, this will power down
the unit.
2. Press and hold the TIMER HOURS/MINUTES key and the TEMP
DOWN arrow key simultaneously for approximately 3 seconds. The
unit should enter Defrost Adjustment Mode as indicated by the speed
display reading ‘dEF’ and temperature display reading ‘ On’ or ‘OFF’.
3. Using the TEMP UP and TEMP DOWN arrow keys, adjust the
defrost feature to either ‘ On’ or ‘OFF’ as desired.
4. Press the POWER key. This will enable or disable defrost based on the
previous selection. If ‘OFF’ was selected, defrost will be disabled and
the operation is complete. If ‘ On’ was selected, continue to set the
other defrost parameters.
MaxQ 6000 Shaker 5-7
Thermo Scientific
Section 5
Operation
Optional
Refrigeration System
Defrost Cycle
Alteration
