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5.4.7 Two temperature zones
These controller types generally allow of controlling a line-up of maximum four refrigerated display cases with
one temperature zone (pilot case and three add-on cases) or two temperature zones (two pilot cases each with
maximumoneadd-oncase).
The pilot cases detect the temperatures necessary for control and input control actuations to the cooling relay.
Temperature sensors of the add-on cases are largely monitored or used for defrosting.
Cold-room temperature controllers UR 141 NK (NT) and UR 141 TK (LT) allow of independently controlling two
temperature zones (two evaporators). Where required, the evaporators in cold-rooms can each be fitted with
two defrost sensors.
5.4.8 Heating circuit control
Controller type: UR 141 NK (NT) and UR 141 TK (LT) only
5.4.9 Operation of cooling relay
Operation of the cooling relay conforms to refrigeration safety requirements and is determined by the controller
type selected:
UA 111, UA 111 D, UA 141, UR 141 NK (NT): N.O. control, i.e. cooling is OFF when the case controller is
de-energized.
UA 121, UA 131, UA 131 DD, and UR 141 TK (LT): N.C control, i.e. cooling is ON when the case controller
is de-energized.
Damage to equipment and goods!Faultyadjustmentofsetpointsentailstheriskofdamagetothe
systemandmerchandise!Thesetpointfortheheatingcircuitmustbesetlowerthanforcooling.
As an alternative to a second temperature zone, the temperature in coldrooms can be controlled with
an auxiliary heating circuit. Heating circuit control comprises plain on-off control. The heating circuit
control relay energizes when temperature reaches the setpoint and hysteresis. It de-energizes when
the temperature exceeds the dead band.
Inthisinstancethesecondzonemustnotbeselected.Onlythenisitpossibletoadjustthesetpoints.
InordertodeactivatetheheatingcircuitregulationtheparameterHt. Cir. Setp.(Menu211i.e.213)
must be set to "--".
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