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Heat pumps · Error codes

York heat pump error codes

York (Johnson Controls) · A niche brand in the UK. 49 codes across 1 product family, each taken from the manufacturer’s manuals.

Find a York engineer →49 codes · reviewed 23 September 2026

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Type the code on your display or a word from its meaning. Each code opens its own page with what it means, whether it is safe and what you can check.

49 codes

CodeMeaningStops?Homeowner check?
bA
T4 sensor out of operation range
Not statedYes
C7
High temperature protection of inverter module
Not statedYes
E0
Water flow malfunction (after 3 times E8)
Not statedYes
E1
Phase loss or neutral wire and live wire are connected reversely
Not statedYes
E2
Communication malfunction between controller and hydraulic module
Not statedYes
E3
Total outlet water temp. sensor (T1) malfunction
Not statedYes
E4
Water tank temp. sensor (T5) malfunction
Not statedYes
E5
Air side heat exchanger temperature sensor (T3) malfunction
Not statedYes
E6
The ambient temperature sensor (T4) malfunction
Not statedYes
E7
Buffer tank upper temp. sensor (Tbt) malfunction
Not statedYes
E8
Water flow malfunction
Not statedYes
E9
Suction temperature sensor (Th) malfunction
Not statedYes
EA
Discharge temperature sensor (Tp) malfunction
Not statedYes
Eb
Solar temp. sensor (Tsolar) malfunction
Not statedYes
Ed
Inlet water temp. sensor (Tw_in) malfunction
Not statedYes
EE
Hydraulic module EEprom malfunction
Not statedYes
F1
DC bus low voltage protection
Not statedYes
F6
EXV1 fault
Not statedYes
H0
Communication malfunction between main control board and hydraulic module board
Not statedYes
H1
Communication malfunction between main control board and inverter board
Not statedYes
H2
Liquid refrigerant temp. sensor (T2) malfunction
Not statedYes
H3
Gas refrigerant temp. sensor (T2B) malfunction
Not statedYes
H4
Three times L0 protection
Not statedYes
H5
Room temp. sensor (Ta) malfunction
Not statedYes
H6
The DC fan malfunction
Not statedYes
H7
Voltage protection
Not statedYes
H8
Pressure sensor malfunction
Not statedYes
H9
Outlet water for zone 2 temp. sensor (Tw2) malfunction
Not statedYes
HA
Outlet water temp. sensor (Tw_out) malfunction
Not statedYes
Hb
Three times PP protection and Tw_out below 7 C
Not statedYes
Hd
Communication malfunction between master unit and subordinate unit
Not statedYes
HF
Inverter module board EEprom malfunction
Not statedYes
HH
10 times H6 in 2 hours
Not statedYes
HP
Low pressure protection in cooling mode
Not statedYes
L0
Inverter or compressor protection
Not statedYes
L1
DC bus low voltage protection
Not statedYes
L2
DC bus high voltage protection
Not statedYes
L3
Current sampling error of PFC circuit
Not statedYes
L4
Rotating stall protection
Not statedYes
L5
Zero speed protection
Not statedYes
L7
Phase loss protection of compressor
Not statedYes
P0
Low pressure switch protection
Not statedYes
P1
High pressure switch protection
Not statedYes
P3
Compressor overcurrent protection
Not statedYes
P4
Compressor discharge temperature too high protection
Not statedYes
P5
abs(Tw_out-Tw_in) value too big protection
Not statedYes
Pb
Anti-freeze mode
Not statedYes
Pd
High temperature protection of air side heat exchanger temperature (T3)
Not statedYes
PP
abs(Tw_out-Tw_in) abnormal protection
Not statedYes