Check Temperature Sensors; Incorrect Circulation In The Solar Circuit - Viessmann SM1 Installation And Service Instructions Manual

Repairs
(cont.)

Check temperature sensors

aVG % & /
Fig. 3
100
10
1
0.1
0 20 25 40
Temperature in °C
Fig. 4
Collector temperature sensor
A
NTC 20 k )
Ω
■ Cylinder temperature sensor
B
■ Temperature sensor
Temperature sensor
■
(sensor type: NTC 10 k

Incorrect circulation in the solar circuit

If code 0d:1 has been set (delivered condition), unwan-
ted DHW circulation (e.g. at night) will be captured. In
"Diagnosis solar" (weather-compensated control
unit) or "Brief scan" (constant temperature control
unit) the number of the captured incorrect DHW circu-
lations can be scanned.
A
aÖ
B
60 80 100
(sensor type:
&
%
/
aÖ
)
Ω
1. Pull plug from the respective temperature sensor
A and check the sensor resistance.
2. Compare the sensor resistance with the curve (see
the following diagram).
3. In the event of severe deviation replace the sensor.
A
120 140
■ Check time indication at the control unit; adjust if
necessary.
■ Check current collector temperature and cylinder
temperature via diagnosis.
Sensors have been interchanged if the collector tem-
perature is too low and the cylinder temperature too
high.
■ Switch off all actuators via a relay test.
If the solar circuit pump continues to run, see "Check
solar circuit pump at output
If the flow and return temperature rises when the
solar circuit pump is switched off, there may be re-
circulation via gravity.
Check any installed check valves or install them if
necessary.
Troubleshooting
".
sF
15