Flow error
Strainer, pressure, air, pump.
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Heat Pump Repair: No Heating, No Hot Water or an Error Code
In short: heat pump stopped, house cooling down, lukewarm water or an outdoor unit full of ice: Service Technic Belgium repairs air-to-water and air-to-air heat pumps of the usual makes (Daikin Altherma, Vaillant aroTHERM, Mitsubishi Ecodan, Panasonic Aquarea, Viessmann Vitocal, LG Therma V…). Call 0477 03 88 98.
Water flow, refrigerant pressures, sensors and the communication between the indoor and outdoor units: the technician follows a fixed order and tells you what he found before he repairs. Changing boards at random is the expensive way to fix a heat pump.
5,0on Google· 22 years of experience
Measure firstBefore any part is changed
Air-to-water and air-to-airMonobloc or split
Error codesRead on the controller
SettingsHeating curve and back-up
The flow error, a winter classic
In the middle of winter, the call we get most is a heat pump stopped on a flow error. The machine protects its heat exchanger: when the water moves too slowly, it would rather stop than freeze or overheat.
The cause is nearly always in the water circuit: a dirty strainer, low pressure, air in the pipes, a closed valve on a radiator or manifold, a tired circulating pump. A badly bled underfloor circuit is enough.
The technician checks the pressure, cleans the strainer, bleeds the air, measures the flow and tests the pump. If there is a lot of sludge in the water, he proposes a flush of the installation and a magnetic filter.
No heating or no hot water
A house that cools while the heat pump runs does not always mean the pump is broken. A badly set heating curve, an outdoor sensor in the sun or a diverter valve stuck on hot water give the same result.
For hot water we look at the tank: sensor, electric element, diverter valve and legionella programme. Hot water that runs out too quickly often comes from a setting that is too low or a tank too small for the family.
If the problem lies in the refrigerant circuit, the technician measures pressures and temperatures. Too little refrigerant points to a leak that has to be found and repaired before any refill.
An outdoor unit full of ice
In cold, damp weather it is normal for the outdoor unit to freeze and defrost a few times a day: it blows out steam and stops for a few minutes. Ice that keeps growing and no longer clears is not normal.
Causes include defrost water that cannot drain and refreezes under the unit, a blocked fan, a faulty defrost sensor, or a unit standing too low or in a corner where the air keeps circulating.
Never chip ice off with a tool: the fins are fragile. Switch the machine off if the manufacturer allows it and call us; the technician checks the defrost and the drain and, if needed, proposes a higher stand or a heater cable.
Error codes by make
Every manufacturer has its own codes: U4 or 7H on Daikin, F.022 or F.070 on Vaillant, codes with P, U or E on Mitsubishi and Panasonic. One code can have several causes, which is why we measure first.
Note the code, the time it appeared and what the machine was doing at that moment: heating, hot water or defrost. A photo of the screen on WhatsApp helps the technician prepare his visit and his parts.
You may reset once by cutting the power for a few minutes. If the code comes back, do not keep resetting: some faults get worse with every restart.
A high bill, a back-up that keeps running
A heat pump that heats but costs too much is also a fault, even without a code. The most common cause is the electric back-up element switching on too early, sometimes at a few degrees below zero or even above.
A heating curve set for very hot radiators, a night temperature that is too high or a daily legionella programme also push consumption up.
The technician reads the counters, looks at the history and adjusts the settings. It is often the visit that pays back most for a limited cost.
Servicing after the repair
A heat pump needs a yearly check: outdoor unit cleaned, water circuit strainer, pressure, expansion vessel, tank, electrical connections and settings. Units with a large refrigerant charge also need a periodic leak test.
Most winter breakdowns give warning signs: a half-blocked strainer, a pressure that slowly drops, a defrost drain that runs badly. The service finds them before the first frost.
After a repair the technician suggests noting the date of the next check. Keep the job sheet; it helps if the manufacturer has to step in later.
Faults we see most
Ice
Defrost or drain.
Lukewarm water
Sensor, valve or setting.
Too much back-up
Heating curve and settings.
Before you call
The code
Photo of the controller or screen.
Make and model
On the label of the units.
The pressure
The figure on the water circuit gauge.
The moment
Heating, hot water or defrost?
How we work
Phone, WhatsApp or online
Use whichever suits you and tell us your neighbourhood.
Time confirmed
You know when the technician will come and what the call-out costs in advance.
Nothing without your OK
Work starts once you have said yes. Keep the job sheet and the invoice for your records.
What our customers say
Heat pumps repaired across Belgium
We repair and service heat pumps in houses, flats and small buildings in all three Regions.
BrusselsWalloon BrabantFlemish BrabantHainautNamurLiègeLuxembourgAntwerpEast FlandersWest FlandersLimburg
Frequently asked questions
My heat pump shows a flow error: what do I do?
Check the pressure of the water circuit and that no valve is closed, then reset once. If the error returns, the strainer needs cleaning, the circuit bleeding or the pump checking: call us.
Is it normal for the outdoor unit to steam in winter?
Yes, that is the defrost: it blows out steam for a few minutes. Ice that stays and grows is not normal.
Do you repair a heat pump fitted by another installer?
Yes, the usual makes, whether we fitted them or not.
Why has my electricity bill gone up?
Often because of the electric back-up or a heating curve set too high. A check of the settings solves most cases.
My heat pump is less than two years old: can you come?
Yes for the diagnosis and the service; if the manufacturer or the installer has to step in, we tell you what to do.
Do you work everywhere in Belgium?
Yes, in Flanders, Brussels and Wallonia. The office gives you the first possible time in your municipality.
How do I book?
Call 0477 03 88 98, send us a WhatsApp message or book online with the « Book an appointment » button. Tell us the municipality and, in a few words, what is going on.
Heat pump no longer heating?
Call 0477 03 88 98 with the make and the error code: a technician comes to measure first and repair second.