34
Faults without on-screen display
Temperature on the DHW side too low
Cause
Remedy
Set DHW temperature value is set too low at the control
unit.
Increase the set DHW temperature value
"T DHW set"
at the control unit; see page 18.
Pressure drop on heating water side too high
Check the pipework on the heating water side and
modify if required.
Control unit is off.
Check the control unit:
■
Check the fuse.
■
Check the power supply.
■
Replace control unit if required.
Air in the system
Vent system.
■
Types PBS and PZS:
Flow sensor with integral temperature sensor
■
Types PBM, PZM and PBL:
Flow sensor or temperature sensor S2
Check both sensors:
■
Check hydraulic connection.
■
Check the electrical connection, cables and earthing.
■
Check proper functioning.
Check the flow sensor; see separate instructions.
Check temperature sensor S2; see page 36.
■
Replace sensor if required.
Flow temperature sensor S1
Check temperature sensor (S1):
■
Check hydraulic connection.
■
Check the electrical connection, cables and earthing.
■
Check flow temperature sensor S1; see page 36.
■
Replace sensor if required.
Primary pump
Check the primary pump:
■
Check hydraulic connection.
■
Check the electrical connection and cables; see
page 7 and separate instructions.
■
Check proper functioning.
■
Replace primary pump if required.
Fluctuating temperature on the DHW side
Cause
Remedy
Air in the system
Vent system.
■
Types PBS and PZS:
Flow sensor with integral temperature sensor
■
Types PBM, PZM and PBL:
Flow sensor or temperature sensor S2
Check both sensors:
■
Check hydraulic connection.
■
Check the electrical connection, cables and earthing.
■
Check proper functioning.
Check the flow sensor; see separate instructions.
Check temperature sensor S2; see page 36.
■
Replace sensor if required.
Draw-off rate is too low
Cause
Remedy
Pressure on the DHW side too low
Check the pressure on the DHW side and increase if
required.
Plate heat exchanger scaled up
Clean plate heat exchanger; replace if required.
Troubleshooting
Fault messages
(cont.)
5517 095 GB
Diagnosis
Summary of Contents for VITOTRANS 353
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