Troubleshooting
3
Subject to modifications resulting from technical improvements!
Buderus Ltd. • http://www.buderus-domestic.co.uk
Servicing manual for wall-mounted condensing gas boiler 600 Series 11S/19S/24S/24C • Issued 02/2006
53
3.1.11 Checking the wiring connections of the UBA
z
Disconnect the system from the power supply.
z
Loosen crosshead screw on UBA housing.
z
Swivel UBA housing downwards.
z
Open the UBA housing.
z
Check all cable terminals for tightness and
resecure/retighten as required.
z
Shut the UBA housing.
z
Swivel the UBA housing upwards and screw into place.
z
Connect system to mains power supply.
3.1.12 Checking the miniature fuses
z
Disconnect the system from the power supply.
z
Loosen crosshead screw on UBA housing.
z
Swivel UBA housing downwards.
z
Open the UBA housing.
z
Check miniature fuses (fig. 60) for correct functioning,
or carry out visual inspection. If defective, fit new fuse
(1.25 AT).
z
Shut the UBA housing.
z
Swivel the UBA housing upwards and screw into place.
z
Connect system to mains power supply.
3.1.13 Checking the connections for the second solenoid
valve,
modulating pump
and floor thermostat
switching contact
z
Pull on mains connection box to detach.
z
Check connections of second solenoid valve (fig. 61,
item 1), modulating pump (fig. 61, item 2) and floor
thermostat switching contact (fig. 61, item 3).
Fig. 59 Checking the wiring connections of the UBA
Fig. 60 Checking the miniature fuse
1
2
3
Fuse
Function
1
Hot surface ingitor
2
UBA, sensors, thermostat valve
3
UBA, three-way valve
Fig. 61 Connections for the second solenoid valve,
modulating pump
and external switching contact
1
2
3
