E903 - Samsung RC090MHXEA Service Manual

E903

E903 is an error with the red back up heater sensor connected to the white plug in the bottom
right hand corner of the PCB of the MIM indoor control PCB, this error only shows if field
setting 4021 is set to 1.
When field setting 4021 is set to 1 this sensor is used to measure the flow temperature, it
replaces the one in the outdoor unit (see fault E902). This sensor should go on the flow pipe
after the backup heater to measure the maximum temperature available from the system.
If you have this fault but don't have a backup
heater then reset field setting 4021 back to 0.
Hybrid systems do not use this sensor.
You can view this sensor in the
test mode from the remote
controller inside.
To access TEST mode press blue set button and
test button together for 6 seconds.
The controller will display TEST.
Press the blue view button twice, a temperature
will be displayed and the word OUT1 shows. This
is the reading from the sensor.
If you compare this with the actual water flow
temperature it should be exactly the same. If they
are different the sensor needs replacing.
To exit service mode press and hold cancel
delete for 6 seconds
www.freedomhp.co.uk ©G Hendra Nov 18 46