Electra Emd 50 - Heaters Operation Rules for RH Groups; OFAN Operation for RC and SH Groups

7-14
CONTROL SYSTEM
Revision Y05-01
Service Manual - EMD Series
4.1.5 Heaters operation rules for RH groups
(a) In RH group, HE operation is according to the difference between RAT and SPT.
-1 0 2
T=SP-RT [
o
c]
HE1
HE2
ON
ON
OFF
OFF
4.1.6 OFAN Operation for RC and SH groups
(i) As a general rule for RC and SH groups, excluding protection modes, OFAN starts with the
compressor.
(ii) When OFAN is then ON it will operate according to the following conditions:
a) OFAN operates together with the compressor.
b) When
50)2( tt ICTandSPTRT
and the 4.7k Ohm resistor is not connected to the
OCT, OFAN will operate according to the following curve:
0 3
ON
OFF
OCT
OFAN