Check Solar Circuit Pump At Output Sf; Check Connection At Output Ss; Check Temperature Sensors - Viessmann SDIO/SM1A Installation And Service Instructions Manual

Troubleshooting
Repairs
(cont.)
Check solar circuit pump at output
Characteristics of the circulation pump (see also the
following chapter):
■ Pump always off:
– High limit safety cut-out has responded. Reset the
high limit safety cut-out.
Output faulty
– sF
Replace the SDIO/SM1A electronics module.
– Solar circuit pump faulty
Replace solar circuit pump.
■ Pump always on:
– Coding address "02" incorrectly set
PWM connection faulty
–
– Output sF always 'live'.
Replace the SDIO/SM1A electronics module.
Multi stage circulation pump
The multi stage circulation pump is switched on and off
via output sF .
Check connection at output
Subject to system scheme, a circulation pump or a
3-way diverter valve can be connected to output
When output sS is on, a voltage of 230 V
present.

Check temperature sensors

aVG % & /
jF
NTC NTC NTC
10 kΩ 20 kΩ 10 kΩ
Fig. 2
16
sF
sS
.
sS
∼
must be
A
aÖ
NTC
10 kΩ
Code/parameter "02:0" must be set.
Variable speed circulation pump with PWM control
Output must indicate a permanent voltage of
sF
∼
230 V . The pump speed is governed by means of a
control signal via PWM connection.
Code/parameter "02:2" must be set.
If the PWM connection is interrupted the circulation
pump must be switched off. If the circulation pump
runs at maximum speed when the PWM connection is
interrupted, an incorrect circulation pump has been
installed.
If output functions correctly during the relay/actua-
sS
tor test but not in normal operation, check setting of
coding address "20".
1. Pull plug of relevant temperature sensor from
SDIO/SM1A electronics module
sensor resistance.
2. Compare the sensor resistance with the curve (see
the following diagram).
3. In the event of severe deviation replace the sensor.
and check the
A