Bosch boiler troubleshooting

Bosch electronics often generates one or another error code in boiler service. The troubleshooting chart with decoding represented below will help to react accordingly and correctly to these or other malfunction in operation of the Bosch equipment and often remove malfunctions on one`s own.

Bosch AKE 30 boiler troubleshooting

ProblemPossible CauseCorrective Action
Chain saw fails to operateKickback brake is activatedPull activation lever for kickback brake (hand guard) 5 back in position O (see figure F)
Plug not connectedConnect plug
Mains socket faultyUse another socket
Extension cable damagedCheck cord, replace
Fuse faulty/blownReplace fuse
Chain saw operates intermittently
Extension cable damagedCheck cord, replace
External or internal wiring defectContact your Bosch Service Centre
On/Off switch 2 defectiveContact your Bosch Service Centre
Saw chain dryNo oil in reservoirRefill oil
Vent in oil filler cap 4 cloggedClean oil filler cap 4
Oil passage cloggedClean oil passage
Brake does not stop saw chainKickback brake/run-down brake defectiveContact your Bosch Service Centre
Saw chain/guide bar hotNo oil in reservoirRefill oil
Vent in oil filler cap 4 cloggedClean oil filler cap 4
Oil passage cloggedClean oil passage
Chain tension too highTension saw chain
Dull saw chainSharpen saw chain or replace
Chain saw rips, vibrates,
does not saw properly
Chain tension too looseTension saw chain
Dull saw chainSharpen saw chain or replace
Chain worn outReplace saw chain
Chain teeth are facing in the wrong directionReassemble with chain in correct direction

Bosch R 30 boiler troubleshooting

ProblemCauseRemedy
Desired room temperature is not reachedThermostatic valve(s) set too lowIncrease thermo- static valve set- ting (s)
Temperature con- trol for CH flow set too lowIncrease CH flow temperature con- trol setting
Air trapped in heating systemBleed radiators and heating sys- tem
Desired room temperature exceeded by large amountRadiators are too hotTurn down ther- mostatic valves
Temperature rises instead of fallingClock is incor- rectly setCheck setting
Room tempera- ture too high in Economy modeBuilding retains heat wellStart Economy mode sooner
No display or dis- play unit does not respondMomentary power failureSwitch off appli- ance at master switch, wait a few seconds and switch on again
Storage Tank doesn’t warm upTemperature con- trol is too lowTurn the tempera- ture control to the desired tempera- ture

Bosch ZBR16-3A boiler troubleshooting

DisplayDescriptionElimination
A7DHW temperature sensor defective.* Check temperature sensor and leads for interruptions or shorts, and replace if defective.
* Insert code plug correctly; replace if defective.
A8Communication fault.* Check BUS communications wiring, replace if defective.
* Check control, replace if defective.
AdDHW tank temperature not detected.
The DHW tank temperature sensor was recognized before the connection was lost.
* Check DHW tank temperature sensor and connecting lead, replace if defective.
* Reset the boiler to the factory default settings (-> service function 8.E), reset the IPM 2 (if installed) to the factory default settings and carry out the automatic system configuration.
blCode plug not detected.* Insert code plug correctly; replace if defective.
b2/b3/
b4/b5/
b6
Internal data error.* Reset boiler to factory default setting (-> service function 8.E).
b7Fault in the burner controls.* Reset boiler to factory to default setting (-> service function 8.E).
C6Fan not running.* Check fan leads and fan, replace if defective.
CCOutdoor temperature sensor not recognized.* Check outdoor temperature sensor and leads for interruptions, replace if defective.
* Verify the outdoor temperature sensor is connected to terminals A and F.
d3Temperature high limit defective. External guard has tripped. Temperature limiter locked out.* Check temperature sensor and leads for interruptions or shorts, and replace if defective.
* Temperature guard TB1 has tripped. Check if jumper across 8-9 or PR-PO is missing.
* Reset external temperature limiter (if installed).
* Reset LWCO (if installed).
d5External supply temperature sensor defective (low-loss header).
The external supply temperature sensor was recognized on the BUS and then reconnected to the appropriate terminal.
* Check temperature sensor and leads for interruptions or shorts, and replace if defective.
* Check whether only one temperature sensor is connected; otherwise remove second temperature sensor.
* Reset the boiler to the factory default settings (-> service function 8.E), reset the IPM 2 (if installed) to the factory default settings and carry out the automatic system configuration.
E2Supply temperature sensor defective.* Check temperature sensor and leads for interruptions or shorts, and replace if defective.
E3Additional supply temperature sensor defective.* Check temperature sensor and leads for interruptions or shorts, and replace if defective.
E9Heat exchanger safety high limit or flue gas temperature limiter has tripped.* Check flue gas safety high limit and leads for interruptions or shorts, and replace if defective.
* Check heat exchanger safety high limit and leads for interruptions or shorts, and replace if defective.
* Check the operating pressure.
* Check temperature limit; replace if defective.
* Check pump capacitor; replace pump if defective.
* Check PCB fuse, replace if blown (6.3 A fuse according to IEC default).
* Purge the appliance
* Check heat exchanger on the DHW side; replace if clogged.
EANo flame detected.
GFA: Safety time expired.
* Check that ground lead is properly connected, replace if defective.
* Check that gas cock is open.
* Check inlet gas pressure; correct if needed.
* Check power supply.
* Check electrodes for visual damage; replace if defective.
* Check flue gas system; clean or repair if defective.
* Check gas/air ratio; correct if out of range.
* Check gas valve; replace if defective.
* In room air operation, check air supply or ventilation apertures.
* Clean the condensate trap.
* Remove diaphragm at fan inlet connection and check for contamination or cracks.
* Check heat exchanger for soiling (-> Chapter 14.1.6, page 84).
* Check gas cock; replace if defective.
* Insert code plug correctly; replace if defective.
FOInternal fault* Press reset for 3 seconds and release. When the button is released, the appliance will restart.
* Check electrical plug-in contacts and ignition leads; replace PCB if defective.
* Check gas/air ratio; correct if out of specification.
FIInternal data error.* Reset boiler to the factory default setting (-> service function 8.E).
F7Flame detected even when burner is off.* Check electrodes; replace if defective.
* Check flue gas system; clean or repair if defective.
* Check PCB for moisture; dry if needed.
FAAfter switching gas off: Flame is detected.* Check gas cock; replace if defective.
* Clean condensate trap.
* Check electrodes and leads; replace if defective.
* Check flue gas system; clean or repair if needed.
FdReset button pressed by mistake.* Press reset button again.
* Check cable harness to safety high limit and gas cock for ground connection.


ProblemsCause/Solutions
Appliance faultsElimination j
Combustion noise too loud; rumbling noises* Insert code plug correctly; replace if defective.
* Check gas type.
* Check inlet gas pressure; adjust if defective.
* Check flue gas system; clean or repair if defective.
* Check gas/air ratio in the combustion air and flue gas; replace gas valve if defective.
Flow noises* Set pump speed correctly to match maximum output.
* Set pump mode.
Heating-up takes too long* Set pump speed correctly to match maximum output.
* Set pump mode.
Flue gas readings incorrect; CO levels too high* Check gas type.
* Check inlet gas pressure; adjust if defective.
* Check flue gas system; clean or repair if defective.
* Check gas/air ratio in flue gas; replace gas valve if defective.
Violent ignition, poor ignition* Check gas type.
* Check inlet gas pressure; adjust if defective.
* Check power supply.
* Check electrodes for visual damage; replace if defective.
* Check flue gas system; clean or repair if defective.
* Check gas/air ratio; replace gas valve if defective.
* Check gas valve; replace if defective.
* Check burner; replace if required.
DHW has unpleasant odor or has a dark color* Perform thermal disinfection of the DHW circuit.
* Replace sacrificial anode in the tank (if installed).
* Consult local water department.
Set supply temperature (e.g. of the FW200 control) exceeded* Switch off automatic anti-cycle timer, i.e., set value to 0.
* Set the required anti-cycle timer, e.g. default setting of 3 minutes.
Condensate in air box* Insert diaphragm in the mixer unit per installation instructions; replace if defective.
DHW temperature is not reached (combi boiler 2WB..-3A only)* Insert code plug correctly; replace if defective.
* Check whether voltage (120 VAC) is present between terminal 1 and terminal 3; repair if defective.
* Check turbine; replace if defective.
Heatronic is flashing (i.e. all buttons, all display segments, burner indicator etc. are flashing)* Replace fuse Si 3 (24 V) (6.3 A fuse according to IEC default).

Error codes and troubleshooting