Viessmann Vitotwin 300-W Installation And Service Instructions For Contractors page 130

Troubleshooting
Fault messages
Fault mes- Cause
sage
"285: Alter- Output monitoring IC has re-
nat SC" corded a short circuit.
"286: Eng Head temperature on the
head over- Stirling engine is too high.
temp"
130
(cont.)
Remedy
Remove both cables from the
capacitor and check the re-
sistance across the Stirling
generator. This must be at
least 4 Ω.
Observe safety instructions
on page 61.
If the fault recurs, notify
Viessmann Technical Serv-
ice.
Check spring length; adjust if
necessary (see page 77).
Check electrical output (code
8200 in diagnostics engine).
If the output is < 500 W, notify
Viessmann Technical Serv-
ice.
Check the temperature dif-
ferential at the Stirling head
thermocouples in steady-
state condition (code 7764
and 7764 in input/output
test). If the differential
> ± 50 K, reposition the ther-
mocouples (remove yellow
connection plug and plug in C
to L or L to C). Then check
electrical output (code 8200
in diagnostics engine). If the
electrical output is too low,
replace the thermocouples.
If the fault recurs, notify
Viessmann Technical Serv-
ice.
Re-
set-
ting
AR
SR