January 22, 2020

Bosch Gas Boiler Error Codes

Bosch Gas Boiler Error Codes

Display Description Remedy
A7 The hot water temperature sensor is defective.
Check for damage or short circuit to the temperature sensor and its wire, replace if necessary

Ad The boiler temperature sensor is not recognized.
Check the boiler temperature sensor and the connection cable

C1 Low fan speed.
Check the mains voltage.
Check flue gas system and clean or repairing if necessary.

C4
Differential pressure switch not
Opens when the fan is off.
Check the differential pressure switch.

C6
Differential pressure switch not
Closes.
Check the fan and its wire with the plug, replace it with
Necessity.
Check the differential pressure switch and drain pipe
Flue gases.

C7 The fan does not work.
Check the fan and its wire with the plug, replace it with
Necessity.

CE
Insufficient filling pressure
Heating system.
Top up with water.

D7 The gas fitting is defective.
Check the connecting cable.
Check the gas fitting, replace if necessary.

E2
Faulty flow temperature sensor
Line (break).
Check for damage or short circuit
The temperature sensor and its wire,
Necessity.

E9
Temperature limiter tripped
Heat exchanger.
Check for damage to the temperature limiter
Heat exchanger and its connecting wire, replace with
Necessity.
Check the working pressure in the heating system.
Check the temperature limiter, if necessary
Replace.
Check pump start, replace pump if necessary.
Check fuse, replace if necessary
Bleed the boiler.
Check the water circuit of the heat exchanger, if necessary
Replace.
Check for damage to the temperature limiter
Flue gases.

EA Flame not detected.
Check the connection of the protective conductor.
Check that the gas cock is open.
Check the gas supply pressure, correct at
Necessity.
Check the connection to the mains.
Check the electrodes with wires, if necessary
Replace.
Check the flue gas system, if necessary
Clean or repair.
Check gas adjustment, correct if necessary.
For natural gas: check the monitoring relay,gas flow
Replace if necessary.
When working with a combustion air intake from a room
Check the air supply to the room and the ventilation
Holes.
Clean the heat exchanger.
Check the gas fitting, replace if necessary.

F7 Although the boiler is turned off, a flame is detected.
Check the contamination of the electrodes, if necessary
Replace.
Check the flue gas system, if necessary
Clean or repair.
Check the humidity of the electronic board, dry with
Necessity.

FA
After switching off the gas supply, it is detected
flame.
Check the gas fitting, replace if necessary.
Check the electrodes and connecting wires when
Need to replace.
Check the flue gas system, if necessary
Clean or repair.
The fan stage has not been set. Set the fan stage.
P The boiler type is not defined. Set boiler type