Viessmann Vitotwin 300-W Installation And Service Instructions For Contractors page 133

Fault messages
Fault mes- Cause
sage
"301: Eng Stirling head control temper-
head overt ature too high.
SW"
"302: Eng Temperature differential be-
head t'cou- tween the Stirling head con-
ple diff" trol and limit thermocouple is
too high.
"303: Eng Stirling head control thermo-
head t'cou- couple faulty.
ple cont"
"304: Eng Stirling head thermocouple
head t'coupl limiting fault.
lim"
(cont.)
Remedy
Check spring length; adjust if
necessary (see page 77).
Check electrical output (code
8200 in diagnostics engine).
If the output < 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.
Check plug-in connection
X205, connecting cables and
plugs to thermocouples on
the Stirling engine.
Troubleshooting
Re-
set-
ting
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