115
16.2
Blocking codes
The following graph describes the blocking codes of the boiler. A blocking code is only a temporary blocking of the
boiler, because of an extraordinary situation. The boiler will continue to operate after stabilisation of this situation.
The display is not blinking, but is lightened up during the blocking period. The boiler is blocking an action, because
of an extraordinary situation. This action will be continued after stabilisation of this situation
Display message
C a s c a d e
B l o c k
9 9 9 , 5
h r s
Reason
Connection failure with one of the boilers of the cascade.
Cause:
The unit is programmed in such a way that none of the boilers in a cascade will fire, if one
has a lockout. One unit has a lockout and therefore the whole cascade is blocked.
Corrective action:
Troubleshoot the fault of the unit in lock-out.
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.
Check the heat exchanger. Heat exchanger fouling (partly blockage) will increase the re-
sistance causing the water flow to drop.
Display message
A n t
i c y c l e
t
i m e
9 9 9 , 5
h r s
Reason
The controller received a new heat demand too fast after the last
ended demand.
Cause:
Opening and immediately thereafter closing of the external thermostat.
Corrective action:
Controlled water flow cools down too quickly after loss of heat demand.
Controlled water flow heats up too quickly after start of heat demand.
Immediately opening and closing of the external thermostat. Check switching differential
of the ON/OFF thermostat.
Controller settings need to be changed. Be aware that the standard settings work fine for
all common systems. When anti-cycling is active, because of immediate heating or cool-
ing of the controlled water flow/temperature, it concerns an unconventional system.
