Function of UA 300 D
14
Version 2.03 27. Juni 2008
3.2.3 Defrosting
Controller type: UA 111 and UA 111 XP
These two controller types do not have a defrost heater. Off−cycle defrosting is controlled by the supply air sen-
sors.
Controller type: UR 141
Defrosting frees the evaporator of ice forming from normal operation. Defrosting takes place either by heating
the evaporator (electric heating element) or off−cycling the compressor. During defrosting, temperature control of
the refrigeration point is inactivated.
Defrosting has a different effect in single−zone or two−zone operation. In single−zone operation, sensors R1.1
and optionally R1.2 (only when connected) act on Defrost Relay 1.
Verdampfer 1
Evaporator 1
Valve1
Return
air
R1.1 R1.2 (optionally)
Supply
air
Defrost
heater 1
UA 300 D
ZNR. 51203 72 630 E0
Refrigeration point
controller
R1.1: Defrost sensor (Terminal Z31/Z32)
R1.2: Optional defrost sensor (Terminal Z51/Z52)
Valve 1: Solenoid Valve 1 relay (Terminal 25/26/28)
Defrost heater 1: Defrost relay 1 (Terminal 43/44)
On the UR 141, parameters cannot be set for a second defrost stage or heating circuit control.
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