Thetford N3000 Series Troubleshooting Manual page 7

Error code 4: DC heater is off when it should be on
Check if all the connections are
OK
Yes
Check if the heater is using
current (+/- 15 A large fridges
and +/- 11 A small fridges)
Yes
Check the resistance of the
heater, is this between min and
max?
Yes
Check if the 20A fuse is OK
Yes
Production date of the fridge?
!!! Note: put fridge off when
measuring the impedance off the
heater !!!
No
No
Heater resistance:
Type MinΩ
N3080 0.90
N3090 0.90
N3100 0.90
No
N3104 0.90
N3108 0.90
N3112 0.90
N3115 0.90
N3145 0.67
No
N3150 0.67
N3175 0.67
Before 22-6-2015?
Serial number < E173S....
After 22-6-2015?
Serial number >/= E173S.....
N3000 - series
connections
No Replace the
MaxΩ
1.16
1.16
1.16
No Replace the
1.16
1.16
1.16
1.16
0.86
No
Change fuse
0.86
0.86
Use for LED:LED KIT:SR 691138
Use for LCD:LCD KIT:SR 691139
Replace power board assembly
(691101)
Restore the
DC heater
DC heater