Service manual

troubleshooting trees
T r o u b l e s h o o T i n g T r e e s • C o m b i t h e r m C t e x p r e s s t e C h n i C a l s e r v i C e m a n u a l • D – 6
No Convection Element Heat with Retherm Option (380-415V, 3PH)
Is N-6 or B5 below set
point?
Is K-41 contactor coil
energized?
Is K-41 contactor closing?
One must be below
set point in order for
convection elements to be
active in Retherm
No
Yes
Yes
No
L1/A1 from RBH X4/412,
L2/A2 from N7 high limit
through A2 on K-42 contactor
No
Yes
Replace K-41 contactor
L1/L2 supplied from K-77
contactor
Is L1/L2 voltage across
terminals 1/3 on K-41
contactor?
No
Is voltage across terminals
2/4 on K-41 contactor?
Replace K-41 contactor
Is K-42 contactor coil
energized?
A1/L1 supplied from RBH X4/410,
A2/L2 supplied from N7 high limit
through K-61 N/C contacts (if
Browning Bar option)
Is there L1/L2 voltage
across terminal 1 at
F10/11 fuses?
Repair wiring between K-42
and F10/11
Is L3 power at terminal 5 of
K-42 contactor?
No
Yes
Yes
No
No
Yes
Yes
L3 supplied to K-41/6
from K-77 contactor
Is there L3 voltage across
terminal 2 of F12 fuses?
No
Yes
Is L3 power at terminal 6 of
K-42 contactor?
Replace K-42 contactor
No
Yes
Is there L3 voltage across
terminal 1 at F12 fuse?
Repair wiring between
K-42 and F12
No
Yes
Is E-41 drawing current on
all legs?
Yes
No
No
No
Yes
Replace blown F12 fuse
Repair wiring between K-41
and E-41
Is voltage across E-41
convection elements?
Ohm out E-41 element and
replace if necessary
Yes
Convection Retherm cycle
is operating