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Heating engineer · Brussels and Wallonia
Bulex error codes
The most common codes for Bulex Thema Condens boilers, with what they mean and what to do.
Codes can differ between models and generations: if in doubt, go by your boiler's manual.
Water shortage in the system (pressure below 0.3 bar).
PressureCheck the pressure gauge. If it's too low, top up the water (if you know how) and bleed the radiators. If the pressure drops again, there's probably a leak: call us.
No water: the temperature doesn't rise even though the burner is on.
PressureCheck the pressure gauge. If it's too low, top up the water (if you know how) and bleed the radiators. If the pressure drops again, there's probably a leak: call us.
Ignition failure (no or too little gas, or electrode).
IgnitionCheck that the gas tap is open, then reset the boiler once. If the code comes back, don't keep trying: repeated resets can lock the appliance. Call us.
The flame goes out during operation.
IgnitionCheck that the gas tap is open, then reset the boiler once. If the code comes back, don't keep trying: repeated resets can lock the appliance. Call us.
Overheating: the temperature safety device (97 °C) has tripped.
CirculationCheck the pressure and that the radiator valves are open. If everything looks fine and the code comes back, the water circulation needs checking (pump, bleeding, sensors): call us.
Poor air intake or flue exhaust (wrong fan speed).
Flue · safetySwitch the boiler off and air the room. This code concerns the flue: call us. If a CO alarm goes off, or anyone has a headache or nausea, get everyone outside and call 112.
Abnormal flame detection.
TechnicianA component or electronics fault: this needs a technician. Don't open the boiler; call us and give the code shown.
Heating flow temperature sensor disconnected (F00) or short-circuited (F10).
TechnicianA component or electronics fault: this needs a technician. Don't open the boiler; call us and give the code shown.
Heating return temperature sensor disconnected (F01) or short-circuited (F11).
TechnicianA component or electronics fault: this needs a technician. Don't open the boiler; call us and give the code shown.
Heating pressure sensor faulty or disconnected.
TechnicianA component or electronics fault: this needs a technician. Don't open the boiler; call us and give the code shown.
Gas valve motor: cables disconnected or faulty.
TechnicianA component or electronics fault: this needs a technician. Don't open the boiler; call us and give the code shown.
Gas valve control (F61) or closing (F62) fault.
TechnicianA component or electronics fault: this needs a technician. Don't open the boiler; call us and give the code shown.
Circuit board memory error.
TechnicianA component or electronics fault: this needs a technician. Don't open the boiler; call us and give the code shown.
This code isn't in the list: call us and give it to us, we'll tell you straight away what's going on.
Source: Bulex, Thema Condens installation manual (0020109430_06, bulex.be). Codes and how they're shown can differ between models: if in doubt, your appliance's manual applies.
First steps
- Write down the code shown: it saves us time.
- Check the pressure gauge.
- Check that the gas tap is open.
- Reset once. If the code comes back, call us.
Practical guides: Top up the pressure · Bleed a radiator · Reset the boiler
A breakdown, a question? Get in touch.
Call us or message us on WhatsApp. Or leave your number, with a photo of the boiler if you like: we'll call you back.
