ACV HeatMaster 25 TC, Installation, Operating And Servicing Instructions

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