Servicing
5
54
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!
5.3.20 Replacing the hot surface ignitor
z
Disconnect the system from the power supply.
z
Remove combustion-chamber cover.
z
Remove the earth (ground) lead from the hot surface
ignitor (fig. 79, item 1).
z
Loosen crosshead screw on UBA housing.
z
Swivel UBA housing downwards.
z
Open the UBA housing.
z
Unplug hot surface ignitor connection cable from UBA
housing (fig. 80).
z
Loosen nut on clamp used to secure earth (ground) lead
(fig. 79, item 2).
z
Detach retaining plate of hot surface ignitor (fig. 79, item 3)
and remove hot surface ignitor.
5.3.21 Measuring the ionisation current
z
Disconnect the system from the power supply.
z
Loosen the plug-and-socket connector of the monitoring
cable and connect the measuring device in series.
Select the µA direct current range on the multimeter.
The multimeter must have a resolution of at least 1 µA.
z
Reconnect the system to the power supply and turn the
chimney-sweep switch to “
1
”.
z
Measure the ionisation current.
The ionisation current must be > 2 µA DC.
z
Enter the reading on the report form.
z
Disconnect the system from the power supply.
z
Remove the measuring device and restore the
plug-and-socket connection to its original state.
z
Turn the chimney-sweep switch to position “
0
”.
z
Refit the cover for 2nd operating level.
z
Reconnect the system to the power supply. When the
display shows “
7
”, press the service button to display “
c
”.
Press the "reset" button. The display shows “
r
”.
Fig. 79 Replacing the hot surface ignitor
1
2
3
Fig. 80 Disconnect the plug-in cable from the UBA housing