Strebel S-CB Px 120, Installation Operating & Maintenance Manual

Page: 98 / 118

S-CB Px 120 Manual 98
Display message
L i n e f a u l t
p u m p o n 9 9 9 , 5 h r s
Reason Bad power supply
Cause:
The supplied power does not comply with the specifications.
Corrective action:
Check if the power supply is connected correctly to the unit.
Check the voltage and frequency. (Should be Life Neutral, Gnd > 230Vac/50Hz).
Make sure there is no signal fail or voltage peaks in the power supply.
Display message
O u t d o o r s e n s o r f a i l
9 9 9 , 5 h r s
Reason No outdoor sensor detected.
Cause:
The unit is programmed to check if an outdoor sensor is present and does not detect an
outdoor sensor.
Corrective action:
Check for loose wiring/connections in the outdoor sensor circuit.
Check the state of the outdoor sensor and replace it if necessary.
Display message
d T B l o c k
9 9 9 , 5 h r s
Reason Temperature difference between flow and return has exceeded
the blocking value, but not the lock out value.
Cause:
The water flow through the unit is too low.
Corrective action:
Check functioning of the pump.
Check/open all valves that might restrict the water flow through the unit.
Check for an external system pump that influences the flow through the unit.
Check if the system resistance exceeds the spare capacity of the unit pump.
Make sure the heat exchanger is clean. Heat exchanger fouling (partly blockage) will
increase the resistance causing the water flow to drop.
Display message
G e n B l o c k
9 9 9 , 5 h r s
Reason
General blocking circuit is activated during operation (general
blocking contacts 7-8).
Cause:
The circuit connected to the general blocking terminals is not closed.
Corrective action:
Check all external components that are connected to the general blocking terminals and
check why the contact is not closing during heat demand.
Cause: If used in combination with flow switch:
The water flow through the unit is too low.
Corrective action:
Check functioning of the pump and the flow switch.
Check/open all valves that might restrict the water flow through the unit.
Check for an external system pump that influences flow through the unit.
Check if the system resistance exceeds the spare capacity of the unit pump.
Make sure the heat exchanger is clean. Heat exchanger fouling (partly blockage) will
increase the resistance causing the water flow to drop.