FAULT FINDING AND DIAGNOSIS
Greenstar i System Compact - 6 720 807 726 (2013/05)
64
7.5
FAULT CODES
Should a fault develop with this boiler (or the system), the boiler will enter a locking or blocking condition, and fault code information will be generated
as described in this section.
LOCKING ERRORS
Locking error
The boiler display will flash a warning triangle and fault code. At the same time a (static) cause code will also be displayed. Manual
intervention is required following clearance of the fault:
▶ Press the reset button on the boiler fascia
Blocking error The boiler will stop operating with no fault data displayed. The cause code, in the info menu, is accessed by pressing the spanner/
return button. The condition will clear automatically when the associated fault clears e.g. waiting for an area to cool. In some cases a
blocking error has a defined time duration prior to changing to a locking condition.
Fault code
Alpha numeric code indicating the fault group
Cause code
Three digit number. During a blocking error (or normal operating status) it is not displayed, but accessed in the info menu via the
spanner/return button. During a locking error the cause code flashes on the display.
Maintenance
codes
These are displayed with the letter H followed by a number. The code advises of a situation that will need some attention but is not a
fault that will stop the boiler from functioning. Some of the common ones are listed:
H11
H13
Hot water outlet sensor defect, hot water can still be delivered but with less control (sensor open/short circuit or out of position)
A time has been set in the Service interval function i.e. 1 to 72 months and that time has expired. Menu 2.5F allows this feature to be
set (1 to 72), a 0 will disable this function.
Fault codes
Cause
codes
Description
Reset type
Possible cause
9A
362
HCM (Heat Control Module)
Reset button
Incorrect HCM fitted
9U
233
HCM (Heat Control Module)
Reset button
Problem with the code plug (faulty or not connected)
b7
257
Internal error
Replace control board.
C6
215
Fan problem
Reset button
Fan running too fast
216
Fan problem
Reset button
Fan running too slow
C7
214
Fan problem
Reset button
Fan not running
217
No airflow after a defined period of
time
Reset button
Fan not running or airflow blocked
D1
240
Return sensor error
Reset button
Sensor wet or damaged (the boiler will block for 300 seconds
before this condition).
241
Return sensor error
Reset button
Sensor disconnected or damaged (the boiler will block for 300
seconds before this condition).
286
Return temperature too high
Reset button
Boiler overheat
E2
222
Flow sensor short circuit
Reset button
Flow sensor shorted or damaged.
223
Flow sensor open circuit
Reset button
Flow sensor disconnected or damaged.
E5
218
Flow temperature too high
Reset button
Primary flow sensor overheated
332
Primary flow sensor has exceeded
110°C
Reset button
Primary flow sensor overheated
E9
219
Safety sensor temperature too high
Reset button
The main heat exchanger has overheated.
Maximum temperature 105C°
220
Safety sensor short circuit
Reset button
Maximum temperature sensor on the main heat exchanger has
failed.
221
Safety sensor open circuit
Reset button
Maximum temperature sensor on the main heat exchanger has not
been recognised.
224
Max temperature thermostat
activated
Reset button
Flue gas thermostat overheat
EA
227
No flame detected after ignition
Reset button
Failure of four ignition attempts. The boiler waits 30 seconds before
another attempt is made.
229
Loss of flame signal during operation
Reset button
An established flame has been extinguished.
This could be caused by:
• moisture in the sump, due to a blocked sump/condensate trap.
• a strong wind into the flue.
234
Gas valve error
Reset button Gas valve coil disconnected
261
Ignition timing error
Reset button
Flame not established during the first 4 seconds ignition period.
Table 20 Locking fault and cause code listing
