ACV HeatMaster 25 TC Installation, Operating And Servicing Instructions page 29

MCBA BLOCKAGE AND ERROR CODES
Codes Description of the fault
Short circuit NTC2
Short circuit NTC3
Short circuit NTC5
NTC1 open circuit
NTC2 open circuit
NTC3 open circuit
NTC5 open circuit
Value of EPROM parameters out of tolerance
Internal error
Flue gas temperature too high (NTC5)
Error during reading of the parameters
Air pressure switch closed when it should have
opened
Water pressure
Incorrect fan speed during start-up
Temperature of the NTC6 sensor too high
Network frequency out of tolerance
Conflicting or invalid cascade address
Internal error
Deviation of the mains frequency > 1.5 Hz
Opening of air pressure switch during burner
operation
Ionisation current too low during burner operation
Gas pressure switch opened during burner
operation
NTC1 or NTC2 sensor deviation
NTC1 or NTC2 sensor faulty
NTC1 or NTC2 sensor stuck
Resolution of the fault
1. Check the connection of the NTC2 sensor
2. Check the wiring of the NTC2 sensor
3. If the problem persists replace the NTC2 sensor
1. Check the connection of the NTC3 sensor
2. Check the wiring of the NTC3 sensor
3. If the problem persists replace the NTC3 sensor
1. Check the connection of the NTC5 sensor
2. Check the wiring of the NTC5 sensor
3. If the problem persists replace the NTC5 sensor
1. Check the connection of the NTC1 sensor
2. Check the wiring of the NTC1 sensor
3. If the problem persists replace the NTC1 sensor
1. Check the connection of the NTC2 sensor
2. Check the wiring of the NTC2 sensor
3. If the problem persists replace the NTC2 sensor
1. Check the connection of the NTC3 sensor
2. Check the wiring of the NTC3 sensor
3. If the problem persists replace the NTC3 sensor
1. Check the connection of the NTC5 sensor
2. Check the wiring of the NTC5 sensor
3. If the problem persists replace the NTC5 sensor
If the problem persists after two "RESET" attempts, reprogramme the MCBA
If the problem persists after two "RESET" attempts, replace the MCBA
1. Check the connection of the NTC5 sensor
2. Check the wiring of the NTC5 sensor
3. If the problem persists replace the NTC5 sensor
1. Press "RESET"
2. If the error persists, replace the MCBA
Check the air pressure switch
Check the water pressure
1. Check the supply voltage of the MCBA
2. If you detect no problems with it, replace the fan
Check the 3-way valve or the valve motor
Check the mains frequency
Check the cascade address
If the problem persists after two "RESET" attempts, replace the MCBA
Check the mains frequency
Check the air pressure switch
Measure the ionisation current
Check the gas pressure switch
Check the NTC1 and NTC2 sensors
Check the NTC1 and NTC2 sensors
Check the NTC1 and NTC2 sensors
EN • 29
664Y5300 • A