Viessmann Cascade control unit - Faults Indicated in the Faults Menu

33
Troubleshooting
Faults indicated in the "Faults" menu
Cause: Flow temperature sensor
not/incorrectly connected or faulty
Result: Functions based on the flow
temperature are failing
Remedy: Check the connections and the
sensor using the resistance table
(see pageĂ34)
Cause: The flow temperature does not reach
the set value less the set temperature
difference within the set period
Result: The control unit stays in use as
normal
Remedy: Check system components. If
necessary, match the set time and/or
temperature difference.
Reset the fault by pressing
twice.
Cause: Outside temperature sensor
not/incorrectly connected or faulty
Result: The control unit changes over to
average outside temperature.
Some functions based on the
outside temperature are failing.
Remedy: Check the connections and the
sensor using the resistance table
(see pageĂ34)
Cause: The flow temperature is too low to
ensure frost protection
Result: The control unit creates a heat
demand. The set flow temperature is
raised for frost protection at least to
the set value.
Remedy: Check system components
5862Ă474ĂGB
Flow temp.
System too slow
Outside temp.
Frost prot. flow