Viessmann OC208HM, Service Instructions For Contractors

Page: 26 / 48

Code Description Possible cause Measures
E41 Flow limiter Inadequate throughput in-
side the hydraulic circuit
Note
The message is automati-
cally acknowledged until
three fault messages in
one hour occur for the first
time.
Check differential pressure
switch, circulation pump and
water filter
Diagnosis
Diagnosis without display on the control unit
Fault Possible cause Measures
Unit operates con-
stantly but without
cooling effect Inadequate refrigerant fill-
ing Top up refrigerant
Filter dryer blocked Replace the filter dryer
Ice on the suction
line The preselected super-
heating is incorrect Increase the superheating
setting
Check refrigerant level
Increased noise
development Lines vibrating Check line retainers (if in-
stalled)
Thermostatic expansion
valve hisses Top up refrigerant
Check filter dryer
Compressor noisy Check compressor mounts
Compressor bearing worn;
replace compressor
Low oil level inside
the compressor One or several refrigerant
or oil leaks in the refriger-
ant circuit Identify and repair leaks
Mechanical compressor
damage Check compressor and re-
place, if required
Oil sump heater faulty Check oil sump heater and
replace, if required
Control unit diagnostics
(cont.)
26
Troubleshooting
5692
695
GB