Servicing
5
50
Installation and maintenance instructions for wall-mounted condensing gas boiler 600 - 11S/19S/24S/24C • 02/2006
Buderus • http://www.buderus-domestic.co.uk
Subject to modifications resulting from technical improvements!
5.3.11 Checking the safety sensor
z
Unplug cable connection from sensor.
z
Measure resistance of sensor (fig. 67, item 1).
z
Use a second-reading thermometer to measure the
temperature around the sensor.
z
Compare readings with values shown intable 8 on
page 52. If there is any mismatch (i.e. > 5%), the sensor is
defective.
z
If the sensor is working correctly, plug it in once more.
5.3.12 Replacing the safety sensor
z
Shut the servicing valve.
z
Drain the 600 - 11S / 19S / 24S / 24C as per the
"Installation and Servicing Instructions".
z
Loosen the plug-in connection (fig. 68, item 1).
z
Unscrew the sensor (fig. 68, item 2) and replace with a new
unit.
z
Plug in cable connection.
z
Open servicing valves.
5.3.13 Checking the safety sensor connection lead
Check to ensure that all plug-in connections on the sensor and
UBA are in order. Note that an incorrectly-inserted plug can
lead to the generation of error messages. Start up the boiler by
pressing the “reset” button.
z
Set the mains switch to “
0
”.
z
Disconnect the system from the power supply.
z
Unplug cable connection from flow sensor.
z
Disconnect 18-pin plug from UBA.
z
Use a continuity tester to check the cable between the
plug-in connection and the 18-pin plug in the UBA.
The test should be carried out on connections 06-18 and
08-18 (fig. 69).
z
If the cables are in order, plug them in.
z
Connect system to mains power supply.
z
Turn the mains power switch to “
I
”.
Fig. 67 600 - 11S / 19S / 24S / 24C:
checking the safety sensor
Fig. 68 600 - 11S / 19S / 24S / 24C:
replacing the safety sensor
NOTE
Fill the 600 - 11S / 19S / 24S / 24C and purge
the system of air.
Fig. 69 600 - 11S / 19S / 24S / 24C:
checking the safety sensor connection lead