Viessmann VITOCAL 300-G Installation And Service Instructions Manual page 145

Messages
(cont.)
Message
System characteristics Cause
D1 Compressor
Compressor fault, heat
pump stage 1 (type BW):
■ Compressor thermal
relay has responded.
■ Separate compressor
motor protection (if
installed) has respon-
ded
Troubleshooting
Measures
■ Reset compressor ther-
mal relay, check setting,
restore delivered condi-
tion ("Standard set-
tings", see menu struc-
ture).
■ Check compressor
electrical connections,
test coil resistance of
compressor motor.
Check compressor
phase sequence.
■ The switching signal
(from thermal relay,
separate motor protec-
tion) can be tested at
connection 215.7.
Note
If overheating occurs,
internal motor protection
prevents a re-enabling of
the compressor for 1-3
hours.
■ If required, have com-
pressor tested by a
refrigeration engineer.
145