Technical data

33
Remove multiway
connector from board
position ST16. Test
resistance across
contacts 17 and 18
(yellow & either black
wires). Is it between 1
kohm and 30 kohm?
Is there continuity
from contacts 17 and
18 to DHW sensor?
Check or replace
DHW sensor.
(Section 15.4.18).
Separate 6 way in-line
connector and check
continuity of red wires
to determine a harness
fault. Repair or replace
wiring
Is the multiway
connector at board
position ST16 pushed
fully home on to the
board?
Push fully home.
FAIL POINT I “Sensor Fault”
No
No No
Yes
Yes
Yes
Test resistance across
contacts 12 & 13
(red wires).
Is it between 1 kohm
and 30 kohm?
Is there continuity
from contacts 12 and
13 to CH sensor?
No
Repair or replace
harness or main
connector or in-line
connector.
No
Replace control board
(Section 15.4.11).
Yes
Yes
Check or replace
CH sensor.
(Section 15.4.17).