Temperature and flow control
The UniSAB III controller adjusts the compressor load by means of input from a PT100 temperature
sensor. A sensor threaded branch and sensor pocket are delivered with the unit. The sensor must
be fitted into the evaporator outlet pipe a minimum of 1 metre away from the evaporator.
Water and brine treatment
Brine and water for industrial refrigeration plants often contain impurities that can create a coating
(fouling) on the heat transferring surfaces. This reduces the heat transmission and in some cases
the coating causes corrosion of the heat transferring surfaces.
Important:
Keep brine and water under observation for both evaporator and condenser.
Consult a water treatment expert concerning additives to the system. The liability of Johnson
Controls Denmark does not include any damage that may occur due to harmful impurities in
the system.
Be aware that all cooling towers and evaporative condensers experience a constant loss of water
due to evaporation. To keep the concentration of impurities low, a bleed system must be installed.
Note:
To obtain the correct mixture, it is recommended to premix secondary refrigerants
(glycol or brine) and to check it subsequently.
R717 detector
Installation of R717 detectors in the room and in the secondary circuit of an indirect system must
be in accordance with
EN 378
and/or local codes and rules. Detectors in the secondary circuit in
indirect systems are recommended regardless of the R717 charge limit according to
EN 378
.
The use of detectors in secondary circuits should be based on a risk assessment covering
assessment of:
• Risk of damaging secondary piping and components material (corrosion).
• Secondary refrigerant, for example, glycol in case of leakage.
Leak detectors should be selected, installed, and maintained in cooperation and accordance with
the recommendations of the detector supplier.
SAB 283-355 A-Frame OHU 6042 and OHU 7650 (including ATEX) Screw Compressor Unit
62
