Table 7 Heat pump problems

General problems

 G1

Customer is not aware of heat regulation (heating curve, heat limit, night setback)

Explain customer heat regulation

90

40%

 G2

Heat pump (i.e. the overall heating system) requires too much energy

Heat pump inspection

44

19%

 G3

Heat pump capacity is too low / too high

Too low: Relieve heat pump (e.g. operate the hot water generation separately); Too high: Ensure long operation cycles, utilise heat pump (e.g. integrate hot water generation)

12

5%

Underlying problems caused by the heat pump (HP)

 HP1

The evaporator is dirty

Clean evaporator

3

1%

 HP2

Air ducts are not free

Unblock air flow

7

3%

 HP3

Heat pump is dirty (e.g. general dirt such as mouse droppings and nuts), or the water drain is not clear

Clean device or water drain

22

10%

 HP4

Heat pump is icing up

A technician must check the defrost function of the device

1

0%

 HP5

The distance between the air ducts (intake, exhaust) is too close which may cause short-circuit flow

–

9

4%

 HP6

Heat pump has major problems (e.g. shows fault signals)

Requires a detailed check by an installer

4

2%

 HP7

Temperature is sensor incorrectly mounted (e.g. is getting direct sunlight)

Install sensor in the correct place

3

1%

 HP8

Refrigerant may no longer be refilled

Replacement with suitable alternative refrigerant

23

10%

 HP9

Refrigerant is subject to approval and has not yet been reported / Refrigerant status is unclear (booklet missing)

Report refrigerant or clarify status

4

2%

 HP10

Refrigerant check is due

Have refrigerant check performed

2

1%

 HP11

Liquid (brine) in the probe is not frost-proof (no or too little glycols)

Refill glycols

4

2%

 HP12

Brine pressure is too low / too high

Refill or drain liquid (water–glycol mixture)

10

4%

 HP13

Brine temperature is too low

In the short term, reduce the load on the heat pump by reducing the operating hours (e.g. reduce the heating curve, reduce the hot water temperature or operate the hot water generation separately); in the long term, regenerate the thermal reservoir in summer

6

3%

Underlying problems caused by additional heaters (AH)

 AH1

Emergency mode (electric auxiliary heating) of the heat pump or water heater is constantly in operation due to error

Solve issue and disable emergency mode

8

4%

 AH2

Emergency mode (electric auxiliary heating) of the heat pump or water heater is activated and might cause unintended high consumption

Disable emergency mode by default or set it to a lower heat limit

16

7%

Underlying problems caused by the heat distribution system (HD)

 HD1

Preset pressure in the expansion tank is too high

Decrease the preset pressure

28

12%*

 HD2

Preset pressure in the expansion tank is too low

Increase the preset pressure

2

1%*

 HD3

Expansion tank is faulty (e.g. full of water, rubber diaphragm broken)

Repair/exchange expansion tank

11

5%

 HD4

Water pressure is too low

Refill of water is recommended

9

4%

 HD5

Water pressure is too high or air inside the system

Drain water or deflate system

5

2%

 HD6

Pressure meter is broken or misadjusted

Exchange or adjust pressure meter

5

2%

 HD7

Heating circuit leakage

Identify and repair leakage

5

2%

 HD8

Heat circulator pump is inefficient (e.g. old, not controllable, incorrectly dimensioned)

Replace heat circulator pump with an efficient pump (if it is broken)

38

17%

 HD9

Heat circulator pump speed is set incorrectly

Decrease speed of heat circulator pump

21

9%

 HD10

The thermostatic valve is malfunctioning, missing or should be checked

Install new thermostatic valve

15

7%

 HD11

Pipes are not or not fully insulated (e.g. domestic heat water pipes, radiator pipes, downwhole heat pipes)

Insulate pipes

20

9%

Underlying problems caused by the hot water system (HW)

 HW1

Hot water storage is calcified

Descale storage every 5 years

73

32%

 HW2

Temperature of the heat storage is too high

Decrease temperature to 55–60 °C

13

6%

 HW3

Temperature of the heat storage is too low

Increase temperature to 55–60 °C

8

4%

 HW4

There is basically no disinfection function

Retrofit disinfection function

57

25%

 HW5

Disinfection program is disabled or requires a frequent manual activation

Trigger manual activation every week / install timer / enable disinfection program

10

4%

 HW6

Disinfection program operates too often

Decrease frequency of disinfection program

7

3%

 HW7

Pipe heating cable is in permanent operation

Install a timer to switch operation on/off

35

15%

 HW8

Pipe heating cable is disabled by the customer

Should be enabled to be in line with regulation

4

2%

 HW9

The circulation pump for the hot water is in permanent operation

Install a timer to switch operation on/off

18

8%

 HW10

Inefficient hot water circulation pump

Exchange hot water circulation pump

3

1%

 HW11

Flow rate of hot water circulation pump is too high / too low

Optimise flow rate

4

2%

 HW12

Hot water production scheduling not aligned with electricity tariff (high/low tariff times)

Scheduling domestic hot water production to cost-optimal times (e.g. high/low tariff times)

22

10%

Underlying problems caused by the heating control system (HC)

 HC1

Heating control interface is broken

Replace heating control interface

1

0%

 HC2

Access to heating control interface is not possible (password-protected)

Request the password from the installer or manufacturer

7

3%

 HC3

Heating curve is too high

Decrease heating curve

131

57%

 HC4

Heating curves are too low or not harmonised with each other

Increase and harmonise heating curves

5

2%

 HC5

Heat limit is too high

Decrease the heat limit

55

24%

 HC6

Night setback is enabled but should be disabled

Disable night setback

88

39%