Helmer Scientific i.Series
®
Ultra-Low Freezer
Service and Maintenance Manual
360173-A/C
27
5 Service
5.1 Refrigerant
CAUTION
• Review all safety instructions prior to recharging refrigerant.
• Maintenance should only be performed by trained refrigeration technicians.
• Avoid sharp edges when working inside the refrigeration compartment.
NOTICE
The refrigeration systems are sealed at the factory. Do not connect gauge manifolds or add refrigerant to either system unless
directed by Helmer Technical Service.
Full initial refrigerant charge varies by models and can be found on the chart below.
Table 9. Refrigerant Charge
Model
Power Requirements
Refrigerant
Initial Charge
iUF116
iUF118
208/230 V, 60 Hz
R-404A (high stage)
R-508B (low stage)
R-601 (low stage)
29 oz. (822 g)
13.5 oz (383 g)
0.77 oz (22 g)
iUF124
iUF126
R-404A (high stage)
R-508B (low stage)
R-601 (low stage)
29 oz (822 g)
15.3 oz. (434 g)
0.89 oz (25 g)
5.2
Chamber Temperature Sensor Error Recovery
If the i.C³ monitoring and control system loses communication with the chamber temperature sensor or if the sensor fails, the i.C³
system will operate the refrigeration system in Emergency Mode to preserve the inventory stored in the freezer.
Notes
• The Emergency Mode alarm will be displayed on the Home screen only.
• If the Emergency Mode alarm is active, contact Helmer Technical Service.
When the refrigeration system is operating in Emergency Mode, the high stage compressor will operate continuously and the low stage
compressor will operate normally, unless one or more of the following conditions occur:
♦
An over-pressure condition in the high stage refrigeration system
♦
A second Sensor Failure alarm (compressor temperature, condenser temperature, or heat exchanger temperature) becomes
active beyond the duration specified in the Sensor Failure time delay setting
♦
The cascade temperature goes above -20°C
The high stage and low stage compressors will be automatically powered off if any of the conditions above are met.
The chamber temperature sensor error may be cleared and the freezer returned to normal operation by following the chamber
temperature sensor error recovery procedure.
NOTICE
Protect items in freezer from extended exposure to adverse temperature.
Perform error recovery
1. Switch back-up battery ON/OFF switch
OFF
; switch AC ON/OFF switch
OFF
.
2. Wait 30 seconds before powering the freezer back on.
3. Switch AC ON/OFF switch
ON
; switch back-up battery ON/OFF switch
ON
.
