Service manual

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CONTROL SYSTEM
ON
OFF
Base
Heater
0
2
OAT
When OAT is faulty the base heater will be “ON” continuously in HEAT mode.
11.5.7 Thermodynamic Protections
11.5.7.1 Protection level definition
Five protection levels are defined:
Normal – No protection
status is ON.
Stop-Rise (SR) – Syste
m is in protection, first level
D1 - System is in prote
ction, second level
D2 - System is in prote
ction third level
Stop-Compressor (SC) – System is in protectio
n fourth level
11.5.7.2 IDU Protection Level
The ODU receives the protection levels from each one of the IDU. The protection levels are
weighted according to the following table:
Protection Level Weight
Normal 0
Stop-Rise 1
D1 2
D2 3
Stop-Compressor 0
The IDU protection level calculated weight according to the following average:
level protection IDU up round
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


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n
IDU
i
weight prtoction
i 1
n





Where,
n- The number of active IDU units.
11.5.7.3 IDU Protections
11.5.7.3.1 Indoor Coil Defrost Protection
ICT
ICT Trend
Fast
Increasing
Increasing No change Decreasing
Fast
Dec
reasing
ICT < -2 SC SC SC SC SC
-2 ≤ ICT < 0 D1 D1 D2 D2 D2
0 ≤ ICT < 2 SR SR D1 D2 D2
2 ≤ ICT < 4 SR SR SR D1 D2
4 ≤ ICT < 6 Norm Norm SR SR D1
6 ≤ ICT < 8 Norm Norm Norm SR SR
8 ≤ ICT Normal
Revision 0
11-15