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We reserve the right to make technical modifications
Buderus Ltd. • http://www.buderus-domestic.co.uk
Servicing manual Gas condensing boiler Buderus 500-24/S, 500-24/C and 500-28/C • Issued 02/2006
63
box 212 Check the Buderus 24V AC external
3-way valve – activation (1)
A
CAUTION!
To prevent damage, do not insert the measuring
electrodes of the multimeter too far into the holes of the
plug-and-socket connection.
z
Take the boiler out of operation, see box 43, 44 or 47.
box 213
z
Remove the power supply plug of the servomotor of the
Buderus 24V AC external 3-way valve.
box 214
z
Put the boiler into operation, see box 51, 54 or 55.
box 215
z
Set the multimeter to “measure AC voltage”.
Minimum measuring range: 40V AC.
z
Open a hot water tap.
z
Adjust the hot water in the "Settings" menu on the DBA
control panel of the boiler to 60 °C, see box 61.
z
Check to see if, during operating code
C [0c]
, 24 V AC
is detected at plug-in contacts “2” and “6”.
z
Close the hot water tap.
z
Check to see if, during operating code
C [0h]
, 24 V AC
is detected at plug-in contacts “2” and “3”.
Plug-in contacts
of Buderus 24V
AC external 3-
way valve
Purpose
Plug-in contacts
on DBA control
panel
2
24V AC
5
3
0V AC
6
6
_ \ __
7
6
3
2
box 216
z
Insert the power supply plug of the Buderus
24V AC external 3-way valve.
z
Put the boiler into operation, see box 51, 54 or 55.
box 217 Replace the Buderus 24V AC external 3-way
valve – servomotor
z
Take the boiler out of operation, see box 43, 44 or 47.
z
Remove the power supply plug of the servomotor of the
Buderus 24V AC external 3-way valve, see box 213.
box 218
z
Remove the servomotor of the Buderus 24V AC external
3-way valve. To release the servomotor press the release
catch (item 1) and twist the servomotor.
A
DANGER OF DAMAGE TO THE SYSTEM!
Before removing the servomotor, check to see if the
Buderus 24V AC external 3-way valve is in its "heating
mode" position, and wait for the boiler display code
C
[0h]
to appear. This prevents sudden pressure surges
occurring in the heating circuit while the removal
operation is taking place, and the resultant accidental
opening of the pressure relief valve.
box 219
z
Fit the new servomotor by following the above procedure
in reverse order.
z
Put the boiler into operation, see box 51, 54 or 55.
