No Display In Programming Unit - Viessmann VITOTRONIC 200 Service Instructions Manual

Troubleshooting
LON subscriber check
Possible displays:
■ No display (status unknown):
Subscriber has not yet registered, but
has not yet been identified as failed.
■ "Failed" :
Subscriber has not registered for more
than 20 min ("Interval for data trans-
fer via LON 779C").
■ "Check" while the subscriber check
runs; "WINK" flashes in the display of
the selected subscriber for approx. 30
s.

No display in programming unit

1. Switch ON system ON/OFF switch.
2. Check heat pump control unit fuse;
replace if required.
3. Check whether there is power at the
heat pump control unit; switch ON
power supply if required.
4. Check the plug-in and threaded con-
nections.
5. Replace programming unit if
required.
6. Replace controller and sensor PCB if
required.
Installation and service instruc-
tions of the relevant heat pump.
96
(cont.)
■ "Check OK"
Communication between both sub-
scribers successful.
■ "OK"/"Fault":
Subscriber has registered. Everything
is OK or the subscriber has a fault.
■ "Check ERR":
No communication between the two
subscribers.
Check the LON connection and LON
parameters.