4.10 OUTSIDE SENSOR FAULT
Disconnect the wires to the outside sensor.
Check the resistance using a suitable multimeter
connected across the Outside Sensor’s terminal pins.
Temperature
Resistance kΩ
0
o
C
31.0 – 35.0
15
o
C
15.0 – 16.5
30
o
C
7.7 – 8.5
Is the Outside Sensor value correct?
YES
YES
Is the wiring securely connected between the
incoming terminal block boiler connection of the
Outside Sensor and the PCB?
Replace PCB
Fit a new Outside Sensor
NO
Securely connect the wiring at the
Terminal Block and the PCB
Is the wiring securely connected at both the boiler and
Outside Sensor?
YES
NO
Securely connect the wiring at both the
boiler and Outside Sensor
NO
4.11 NO CH OPERATION BUT DHW WORKS OK
Is “Off” shown underneath the rad on the display?
NO
YES
Press Mode button (C) until “Off” not shown
Are CH Timer and Room Thermostat switched on?
YES
NO
Switch CH Timer and Room Thermostat On
Are the Radiator Valves Open?
YES
NO
Open the Radiator Valves
Is there 230 V AC?
YES
NO
No voltage from Timer/Room Stat
This is not a boiler fault
Ensure voltage is supplied to boiler by rectifying
external wiring
Replace the Divertor Valve
YES
If an OpenTherm Room Stat is not connected, is
there a link wire across the OpenTherm connections
(B) ?
NO
Connect a link wire across the OpenTherm
connections
60
Installation and Servicing
Section 4 - Fault Finding
FAUL
T FINDING
