Buderus 500 - 28/C Servicing Manual page 54

7 Actions
box 146
Set the multimeter to "measure direct current".
Measuring range: Microamperes [µA].
Connect the multimeter in series the ionisation circuit.
Put the boiler into service mode, see box 54, 55 or 13.
Check to see if the ionisation current, during service mode,
operating code C [lo] , > 5 µA (micro amperes) and,
with operating code C [hi] , > 25 µA.
The value is 0 (zero), or between 1.3 and 50 µA.
box 147
Take the boiler out of operation, see box 43 or 44.
Detach the multimeter.
Connect the plug of the ionisation electrode.
Turn the operating switch on the boiler to position "0",
see box 55.
Put the boiler into operation, see box 51, 54 or 55.
box 148 Check the ionisation electrode – short circuits
Take the boiler out of operation, see box 43, 44 or 47.
Loosen the plug-in connection of the ionisation electrode,
see box 144.
box 149
Set multimeter to "measure resistance".
Take a reading at the electrode to check whether there is
a possible short circuit between the ionisation electrode
and earth (ground). The electrical resistance between the
ionisation electrode and earth (ground) must be infinitely
high.
We reserve the right to make technical modifications
54 Servicing manual Gas condensing boiler Buderus 500-24/S, 500-24/C and 500-28/C • Issued 02/2006
box 150
Connect the plug of the ionisation electrode.
Put the boiler into operation, see box 51, 54 or 55.
box 151 Check the ionisation electrode – cable
H
DANGER OF FATAL ACCIDENT
due to electric shock
Take the boiler out of service and tip the DBA control panel
forwards, see box 43, 44, 47 or 63.
Loosen the six screws and remove the rear section,
see box 70.
Remove the plug of the ionisation electrode, see box 144.
box 152
Set the multimeter to "measure resistance".
Take a reading at the ionisation electrode to check
whether there is a possible break in the cable of the
electrode. The electrical resistance of the cable must be
Ω
approximately 0 .
box 153
Take an earth (ground) reading check whether there is a
possible short circuit between the cable of the ionisation
electrode and earth (ground). The electrical resistance
between the ionisation electrode cable and earth (ground)
must be infinitely high.
Buderus Ltd. • http://www.buderus-domestic.co.uk
JP4