Electra DELTA 25, Service Manual

Page: 32 / 75

11-5
CONTROL SYSTEM
Revision Y05-01 Service Manual - Delta DCI
11.4.2 Indoor Fan Control in Heat Mode
Indoor fan speed depends on the indoor coil temperature:
11.5 Auto Cool/Heat Mode
When in auto cool heat mode unit will automatically select between cool and heat mode according
to the difference between actual room temperature and user set point temperature (ΔT).
Unit will switch from cool to heat when compressor is off for 3 minutes, and ΔT < -3.
Unit will switch from heat to cool when compressor is off for 5 minutes, and ΔT < -3.
11.6 Dry Mode
As long as room temperature is higher then the set point, indoor fan will work in low speed and
compressor will work between 0 and
MaxNLOADIF1C Hz.
When the room temperature is lower than the set point, compressor will be switched OFF and
indoor fan will cycle 3 minutes OFF, 1 minute ON.
11.7 Protections
There are 5 protection codes.
Normal (Norm) – unit operate normally.
Stop Rise (SR) – compressor frequency can not be raised but does not have to be decreased.
HzDown1 (D1) – Compressor frequency is reduced by 2 to 5 Hz per minute.
HzDown2 (D2) – Compressor frequency is reduced by 5 to 10 Hz per minute.
Stop Compressor (SC) – Compressor is stopped.
11.7.1 Indoor Coil Defrost Protection
ICT
ICT Trend
Fast
Increasing
Increasing No change Decreasing
Fast
Decreasing
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
ICTVL ICTT ICTH ICTL
ICTST