Nothing Displayed On Programming Unit Screen - Viessmann Vitotronic SPS Service Instructions Manual

Conditions for enabling and automatic starting...
1. Conditions for "Enable heat pump"
■ Power supply utility enable (in status indicator)
Switch on heat pump page (system ON/OFF)
■
System ON/OFF switch on main page (in status
■
indicator)
■ Stage 1 enabled on site
■ No evaporator faults (alarm symbol)
■ Condenser not in manual mode and switched off
(hand symbol)
More than 3 minutes have elapsed since change-
■
over to re-cooling
■ More than 3 minutes have elapsed since commis-
sioning the control unit
If the heat source is groundwater: No frost or
■
groundwater circuit flow alarm (alarm symbol)
■ At least 1 compressor is OK (no compressor
alarms, alarm symbol)
■ Refrigerant circuit is OK (no refrigerant circuit
alarms, alarm symbol)
Not all compressors have been switched off man-
■
ually (hand symbol)
■ System ON/OFF on heat pump page (no other
information except heat pump enable is deactiva-
ted)
Note
Only when all conditions are met will the status indi-
cator turn green (general status).
2. Conditions for starting the heat pump
■ Heating or cooling demand or DHW demand
A certain minimum differential between set and
■
actual value

Nothing displayed on programming unit screen

1. Check the voltage on the display.
2. Check Ethernet connection via switch.
(cont.)
3. Check network settings.
4. Replace the programming unit.
Troubleshooting
53