Cooling Mode Protections; Indoor Coil Defrost - Electra WNG 7 Service Manual

CONTROL SYSTEM
12.9 Protection
12.9.1

Cooling Mode Protections

Indoor Coil Defrost

Mode: Cooling, Dry, Auto
Temp: Selected desired temp.
Fan: Any
Timer: Any
I Feel: On or Off
Control Function
Protect the indoor coil from ice formation at low ambient temperature.
o
ICT [ c]
+14
+5
+2
+1
0
-1
-6
t1 t2
ON
OFAN
OFF
ON
COMP
OFF
ON
IFAN
OFF
t1 = 5 min minimum for each COMP starting
t2 = OFAN cycling (alternate between ON and OFF every 30 sec) for 20 min
maximum
t3 = COMP and OFAN stop for 10 min minimum
Notes:
•
When J7 is closed (connected), OFAN cycling is cancelled and the
set temperature for COMP & OFAN cut-out and cut-in are changed.
COMP & OFAN are forced OFF when ICT =< -6
until ICT > 14
•
For WAX model, the defrost processes is simpler. When J7 is open,
COMP & OFAN are forced OFF when ICT =< -1
until ICT > 5
same as that of the other models (R.H.S. of the graph above). In both
cases, the ICT checking in t2 and t3 are not applied.
12-18
t3 t1
J7 OPEN
o
c.
o c. When J7 is closed, the WAX defrosting process is the
Revision Y05-03
CONTENT
t1
J7 CLOSED
o
c, and are kept OFF
o c, and are kept OFF
Service Manual - WNG