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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 F
ault”
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).