Heat Pump Error Codes Explained Call Igloo Heating Dorset for Fast Same Day Help
- Igloo Heating
- Aug 23
- 8 min read
A heat pump fault code always seems to appear at the worst time. The house cools down, the hot water runs out, and the display flashes a code that looks more like a password than useful information.
The good news is that an error code is not random. It is the heat pump’s way of telling you where to look first. Some faults are simple to check yourself, such as low pressure, frozen outdoor coils, blocked filters, or a tripped switch. Others need a trained engineer, especially when electrics, refrigerant, main components, or gas systems are involved.
This guide explains how to read heat pump error codes, what you can safely try before calling for help, and when to call Igloo Heating in Dorset for fast support across Poole, Christchurch, Bournemouth, Southampton, Ringwood, Dorset, and Hampshire.
What a heat pump error code is really telling you
A heat pump uses sensors, controls, pumps, fans, heat exchangers, and safety devices to keep your heating and hot water running. When something moves outside its expected range, the control board records a fault and shows an error code.
That code may point to:
Water pressure problems
A flow issue in the heating circuit
A frozen or blocked outdoor unit
A sensor reading that is too high or too low
An electrical fault
A communication fault between indoor and outdoor units
A refrigerant or compressor issue
A problem linked to a hybrid boiler or gas appliance
The code does not always name the failed part. It often tells an engineer which system area has reported the fault. For example, a flow error might be caused by a blocked filter, a stuck pump, air in the system, closed valves, or a sensor fault.
That is why the best first step is to write the code down exactly as it appears before turning anything off. Include any letters, numbers, flashing lights, or symbols.
First checks you can safely do at home
Before booking a call-out, a few simple checks may help you understand the fault. Some may even get the system running again.
Only do what feels safe. If there is burning smell, water near electrics, damaged cables, repeated tripping, or any sign of gas trouble on a hybrid system, stop and call a qualified engineer.
Check the display and record the full fault
Take a clear photo of the controller or display. If the code changes, take another one. This helps an engineer diagnose the fault more quickly.
Look for:
The main fault code
Any warning icons
The heating mode shown on the screen
The hot water mode shown on the screen
Whether the fault clears and returns
If you have the manufacturer’s manual, look up the code. Most manuals include a fault code table. Treat this as a guide, not a final diagnosis.
Check whether the system has power
A heat pump may show a fault after a power cut, surge, or tripped breaker.
Check:
The heat pump isolator is on
The fused spur is on
The consumer unit has not tripped
The controller has power
The outdoor unit looks powered, if safe to view
Do not repeatedly reset a breaker if it trips again. That points to a fault that needs investigation.
Check the water pressure
Many heat pump systems need the heating circuit to sit within a set pressure range. The correct range depends on the system, but domestic systems often have a pressure gauge near the cylinder, buffer tank, or plant area.
Low pressure can cause circulation faults, flow errors, or lockouts.
If you know how your filling loop works and your installer has shown you the correct pressure, you may be able to top it up carefully. If you are unsure, do not guess. Overfilling can create more problems.
Call Igloo Heating if:
The pressure keeps dropping
You can see a leak
The pressure rises too high
You cannot find the filling loop
You are not confident topping it up
Check radiators, valves, and filters
Poor circulation can trigger heat pump fault codes. Walk around the heating system and look for simple causes.
Check that:
Radiator valves or zone valves are not all closed
Underfloor heating manifolds look normal
Magnetic filters or strainers are not obviously leaking
The condensate drain is not blocked or frozen
Any visible pipe insulation is still in place
Do not dismantle filters unless you know exactly how to isolate the system and release pressure safely.
Check the outdoor unit
Air source heat pumps need clear airflow. Leaves, bags, garden debris, snow, ice, and overgrown plants can restrict the outdoor unit.
Look for:
Ice build-up that does not clear after a defrost cycle
Leaves stuck to the grille
A blocked fan area
Damage to the casing
Unusual noise from the fan
Water pooling where it should drain away
Do not poke tools through the grille. Do not pour boiling water over the unit. Warm water may be used with care in some frozen drain situations, but if the unit is heavily iced or the fan is stuck, it is safer to call an engineer.
Common heat pump error code categories
Manufacturers use different code formats, so one brand’s `E1` may not mean the same as another brand’s `E1`. Instead of guessing from the number alone, think in categories.
Error code area | What it may mean | Safe first check |
Low water pressure | The heating circuit may not have enough pressure | Check the system gauge and look for leaks |
Flow fault | Water may not be moving properly through the system | Check valves, filters, and whether all zones are closed |
Outdoor unit fault | Airflow, ice, fan, or sensor issue | Check for debris, heavy ice, or blocked drainage |
Sensor fault | A temperature or pressure sensor may be reading incorrectly | Record the code and call an engineer |
Communication fault | Indoor and outdoor units may not be talking properly | Check power, then avoid repeated resets |
Refrigerant fault | Pressure or temperature readings may be outside safe limits | Call a qualified heat pump engineer |
Electrical fault | Control board, supply, motor, pump, or wiring issue | Stop using the system if breakers trip |
Hybrid or gas-linked fault | Boiler, gas valve, flue, or combustion-related issue | Call a Gas Safe registered engineer |
A reset can sometimes clear a temporary fault. For example, the system may recover after a short power interruption. But a fault that returns is a real warning. Repeated resets can hide the cause and may put extra strain on parts.
When a heat pump fault needs an engineer
Some checks are fine for a homeowner. Others are not. A heat pump combines water, electricity, moving parts, and refrigerant. Hybrid systems may also involve gas appliances.
Call a professional if you notice any of the following:
The same code returns after one reset
The unit trips the electrics
The outdoor fan does not turn when it should
The unit is noisy, vibrating, or grinding
The system loses pressure again after topping up
There is water leaking from the cylinder, valves, or pipework
Heating works but hot water does not
Hot water works but heating does not
The fault mentions refrigerant, compressor, inverter, or high pressure
The controller is blank despite power being on
There is a smell of burning
A hybrid boiler shows a gas or flue fault
If you smell gas, turn off the gas supply if safe, avoid flames and switches, open windows, leave the property, and call the National Gas Emergency Service on 0800 111 999.
Igloo Heating is Gas Safe registered, which matters if your system includes a boiler, gas backup, or hybrid heating setup. Gas work should only be carried out by a Gas Safe registered engineer.
Why error code diagnosis is faster with the right information
A little preparation can make a same-day repair more likely. When you call an engineer, give as much detail as possible.
Have these details ready:
The heat pump make and model
The exact error code
When the fault first appeared
Whether heating, hot water, or both have stopped
Any recent work on the system
Whether there was a power cut
The pressure gauge reading, if visible
Photos of the controller and outdoor unit
Any unusual noises, leaks, or ice build-up
This helps Igloo Heating bring the right tools and parts where possible. It also helps the engineer decide whether the fault is likely to be a quick fix, a component issue, or a system design problem.
A heat pump error code is a starting point, not the full diagnosis. The cause may be simple, but the safest repair depends on the whole system.
Why choose Igloo Heating in Dorset
When heating stops, speed matters. Igloo Heating provides a 24 hour call-out service and can often fix most faults the same day, depending on the fault, access, and parts required.
Igloo Heating supports homes and properties across:
Poole
Christchurch
Bournemouth
Southampton
Ringwood
Dorset
Hampshire
The team is fast, reliable, and experienced with heating fault diagnosis. Whether the issue is a heat pump lockout, a pressure fault, an outdoor unit problem, a hot water fault, or a gas-linked hybrid system, Igloo Heating can help you work out the next step.
For urgent help, call:
07547 939494
You can also email:
Or visit:
What happens during a heat pump fault visit
A good repair visit does more than press reset. The engineer should find out why the system locked out.
A typical visit may include:
Checking the fault history
Testing power supply and controls
Checking water pressure and flow
Inspecting filters, strainers, pumps, and valves
Checking the outdoor unit for airflow or fan issues
Looking for leaks or pressure loss
Testing sensors where needed
Checking hot water cylinder controls
Assessing hybrid boiler operation if fitted
Resetting and testing the system after repair
If the fault is simple, such as pressure, air, a blocked filter, or a control setting, it may be fixed quickly. If a part has failed, the engineer can explain what is needed and whether a temporary safe solution is possible.
How to reduce future heat pump error codes
A heat pump works best when water flow, airflow, controls, and pressure all stay within range. Regular care can reduce fault codes and improve reliability.
Simple habits help:
Keep the outdoor unit clear of leaves and debris
Do not stack items around the fan
Check the pressure gauge from time to time
Report small leaks early
Keep thermostats and timers set sensibly
Do not switch the system on and off constantly
Book servicing as recommended by the manufacturer
Make sure filters and strainers are cleaned during service visits
Insulate exposed pipework where suitable
Ask an engineer to review repeated lockouts
Heat pumps often run for longer periods at lower temperatures than traditional boilers. That is normal. Short cycling, loud operation, constant lockouts, or rooms never reaching temperature are signs that the system needs attention.
Follow Igloo Heating’s work online
If you want to see recent jobs, heating tips, and examples of the work Igloo Heating carries out across Dorset and Hampshire, follow the team on social media:
Social updates can be useful if you are comparing heating solutions, spotting common faults, or planning maintenance before winter.
Get help before a small fault becomes a bigger repair
Heat pump error codes are there to help. Record the code, check the simple things, and avoid repeated resets if the fault comes back. If the issue involves electrics, refrigerant, leaks, pressure loss, no heating, no hot water, or a gas-linked system, it is time to get expert help.
For fast, reliable support in Poole, Christchurch, Bournemouth, Southampton, Ringwood, Dorset, and Hampshire, call Igloo Heating in Dorset on 07547 939494. With 24 hour call-out availability and same-day help often possible, you do not have to sit in the cold trying to decode the fault on your own.
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