89750147 Crouzet USA, 89750147 Datasheet - Page 63

• Manufacturer Part Number: 89750147
• Description: STAINLESS SLEEVE-MILL TEMP PRB
• Manufacturer: Crouzet USA

Specifications of 89750147

• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

For more information www.crouzet.com
Connections
Principles
1
+18˚C
-3˚ C
OFF
ON
S2
S1
R
2
3
U
T= t1 + t2 + t3
Th
t1
5
4
6
7
t2
B1
Z1
Z2
A1
A2
11
14
12
R
t3
10mn
B1
Z1
Z2
A1
A2
11
14
12
B
C
D
E
F
G
H
Auxiliary power supply contact
Compressor control thermostat
Compressor contactor coil
Compressor control
Probe
Power supply
Defrost control
Operating principle
The NFR defrost relay can be used to optimize the operation of the exchanger in air-conditioning or
refrigeration unit.
Compact in size, and with IP20 protection, it is easy to install using screws or by fixing on a DIN rail.
The temperature probe supplied with the NFR relay can be disconnected, and should be placed on
the exchanger.
The standard length of the cable between the probe and the NFR relay is 1.6 m. Other lengths are
available to order depending on quantity.
With a choice of different defrosting times, the unit is easily adapted to the particular installation
conditions.
Operating mode
In an air-conditioning system, when the surface temperature of the exchanger between the cooling
fluid and the air is too low, frost forms on the surface and the exchanger performs less efficiently.
Defrosting is then necessary by reversing the cycle or using heating resistors.
When the the total operating time of the set reaches time T (eg : 50 min) while the surface
temperature of the exchanger is below 01 (- 3 °C) , the defrost cycle is determined as time t (10
min). The defrost cycle stops before the end of this time period if the temperature of the cold
exchanger exceeds 02 (18 °C).
If pressed for more than 2 seconds, the button on the top initiates a defrost cycle (if the probe
temperature is below 18 °C). This stops automatically at the end of 10 minutes or immediately if
one of the power supply wires (terminals A1 or A2) or probe wires (terminals Z1 or Z2) is
disconnected momentarily.
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