Fault finding and diagnosis
Greenstar 4000 – 6 720 891 162 (2020/09)
70
10
Fault finding and diagnosis
This fault finding information is for guidance only. Worcester cannot be
held responsible for costs incurred by persons not deemed to be
competent.
This fault finding system assumes that the appliance has been operating
normally until the time of failure (i.e. not a first time installation error).
Basic checks
• Ensure that there is 230V power supply and the polarity is correct to
the appliance.
• Ensure that the appliance settings and functionality is correct.
• Ensure the CH/DHW programmer/timer is functioning.
• Ensure the room thermostat is functioning.
• Ensure the cylinder thermostat (if fitted) is functioning.
• Ensure the cold water mains is turned on.
• Ensure the primary system has adequate pressure/system content
for the system type.
• Ensure there is gas to the appliance.
– Are other gas appliances working, gas cooker/hob for example?
– Has the credit run out on the gas pre-payment meter?
NOTICE
On completion of the Service/Fault-Finding task which has required the
breaking and remaking of electrical connections, check:
▶ Earth continuity,
▶ Short circuit check,
▶ Polarity,
▶ Resistance to earth.
10.1
Operating and fault displays
10.1.1 General information
•
Fault code
: indicates which fault is present.
•
Fault category
: indicates what kind of fault is present and its effects.
Fault category O (operating code)
Operating codes indicate the operating conditions in normal operation.
Fault category B (blocking faults)
Blocking faults result in the heating system being shut down temporarily.
The heating system restarts automatically as soon as the blocking fault is
removed.
Fault category V (locking faults)
Locking faults result in the heating system being shut down, and the
system can only be restarted after a reset.
▶ Press the
and
keys, until
Reset
is displayed.
The appliance resumes operation.
If a fault persists:
▶ Rectify the fault according to 10.1.2 Fault code table
Fault category W (maintenance codes)
