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Heat pumps · Error codes

Sime heat pump error codes

Sime · A niche brand in the UK. 48 codes across 1 product family, each taken from the manufacturer’s manuals.

Find a Sime engineer →48 codes · reviewed 24 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.

48 codes

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