BoilerFaultCodes +D
Domestic hot water NTC fault
Worcester Bosch Greenstar Highflow Fault codes & diagnostics
70 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
Gas 2004 onwards Discontinued
GC Numbers 47-311-8247-311-83
Download the Worcester Bosch Greenstar Highflow manual
PDF
Versions & GC numbers
The fault code is already on your display
Note it down before pressing reset — resetting clears the code immediately. How to read fault codes →
Severity at a glance
Each cell = one fault code. Hover to identify. 70 Unrated
Which version do you have?
The GC number on your boiler's data badge identifies the exact appliance and production years, as recorded in the UK Product Characteristics Database.
| GC number | Appliance (register name) | Produced |
|---|---|---|
| 47-311-82 | Greenstar Highflow 440 | 2004–2008 |
| 47-311-83 | Greenstar Highflow 440 | 2004–2008 |
Appliance names and production years are taken from the UK Product Characteristics Database (the SAP/SEDBUK register). Where a GC number is also printed in this model's own manufacturer manual, both sources were checked to agree.
Just want the most common Worcester Bosch Greenstar Highflow faults?
The top 6 problems in plain English — with causes, DIY checks and repair costs.
Fault codes
All 70 documented codes
Tap any card for details
+E
Domestic hot water NTC fault
+F
Domestic hot water NTC fault
1
Air pressure switch failed to close
1C
Fan fault
1D
Flow sensor fault
1E
Water pressure fault
2$
Reset button pressed by mistake
2D
Fault detected, no flame
2F
Technical fault detected, all gas blocked
Showing 11–20 of 70
4
No pilot flame detected
6
No pilot flame detected
6+
Flow sensor speed not detected
7
Flame signal lost during operation
7,
Domestic hot water NTC fault
7+
Domestic hot water NTC fault
7C
Domestic hot water NTC fault
7D
Domestic hot water NTC fault
7E
Domestic hot water NTC fault
7F
Domestic hot water NTC fault
Showing 21–30 of 70
8
Overheat thermostat tripped
8,
Domestic hot water NTC fault
8?
Domestic hot water NTC fault
8@
Primary NTC fault
8+
Domestic hot water NTC fault
8C
Domestic hot water NTC fault
8D
Primary NTC fault
8E
Primary NTC fault
8F
Domestic hot water NTC fault
9+
Fan speed too low
Showing 31–40 of 70
15
External boiler fault (flow sensor fault)
16
External boiler fault (internal sensor short)
17
External boiler fault (external sensor fault)
18
Ignition failure or boiler lock out
19
Flame signal lost during operation - lockout
21
Flame signal lost during operation - lockout
22
Internal boiler fault (short circuit)
24
External boiler fault (external sensor disconnected)
25
Reset button pressed by mistake
28
External boiler fault (connection from boiler)
Showing 41–50 of 70
29
External boiler fault (cylinder sensor fault)
77
Domestic hot water NTC fault
78
Domestic hot water NTC fault
87
Domestic hot water NTC fault
88
Domestic hot water NTC fault
A7
NTC flue gas temperature sensor
A8
Connection to BUS interrupted
C
Primary NTC fault
C1
Fan speed incorrect
C6
Fan speed incorrect
Showing 51–60 of 70
D
Primary NTC fault
D1
NTC flow sensor
D3
External temperature sensor
E
Air pressure switch opened during operation
E+
Primary NTC fault
E2
NTC flow sensor
E5
Internal fault
E8
Components A-B no power
E9
Safety temperature limiter triggered
EA
No flame detected
Showing 61–70 of 70
F
Air pressure switch opened during operation
F0
Internal fault
F1
Internal fault
F7
False flame detection
FF
Fan speed data invalid
N
External boiler fault (pump fault)
P?P
Appliance lock out: The system setup requires the boiler to restart.
P/P
Safety lock out: The boiler indicates an external connection fault.
P5P
Safety lock out: The boiler indicates air connection fault.
P6P
Ignition lock out: The system setup requires the boiler to restart.