Buderus 500 - 24/C, Servicing Manual

Page: 21 / 80

Diagnosis 6
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Servicing manual Gas condensing boiler Buderus 500-24/S, 500-24/C and 500-28/C • Issued 02/2006 21
6 Diagnosis
box 21
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No indication on DBA control panel display.
step 1
Check to ensure that the power supply cable to the mains switch box has been installed correctly.
step 2
Is the power supply cable to the mains switch box correctly installed? Yes:
→
step
4
No:
→
step
3
step 3
Install the power supply cable correctly, see box 54.
→
box
42
step 4
Check to ensure that the operating switch on the boiler DBA control panel is set to position “1” as per box 55.
step 5
Is the operating switch on the boiler DBA control panel set to “I” (ON)? Yes:
→
step
7
No:
→
step
6
step 6
Turn the operating switch on the DBA control panel of the boiler to position “1” (ON), see box 55.
→
box
42
step 7
Check to the ensure that there is a 230V AC power supply at the mains switch.
step 8
Is there a 230V AC supply at the mains switch? Yes:
→
step
10
No:
→
step
9
step 9
Deal with any problem in the electrical system.
→
box
42
step 10
Measure the resistance of the 230V AC power supply cable.
step 11
Is the resistance of the 230V AC power supply cable within the specified limits? Yes:
→
step
22
No:
→
step
21
step 12
Replace the cable loom (or the affected part thereof).
→
box
42
step 13
Use a multimeter to check the fuse on the inside of the DBA control panel, see box 62 to 65.
step 14
Is the fuse working correctly? Yes:
→
box
41
No:
→
step
15
step 15
Replace fuse, see box 62.
step 16
Is there any indication on the DBA control panel display? Yes:
→
box
42
No:
→
step
17
step 17
Turn the operating switch on the DBA control panel of the boiler to position “0” (OFF), see box 43.
step 18
Disconnect the following boiler components from the electrical power supply:
– pump, see box 92
– fan, see box 71, item 1.
step 19
Check the fuse again for correct functioning. Use a multimeter to check the fuse on the inside of the DBA
control panel, see box 62.
step 20
Is the fuse working correctly? Yes:
→
step
22
No:
→
step
21
step 21
Replace fuse again, see box 62.
step 22
Turn the operating switch on the DBA control panel of the boiler to position “1” (ON), see box 55.
step 23
Is there any indication on the DBA control panel display? Yes:
→
step
27
No:
→
step
24
step 24
Use a multimeter to check the power supply cables of the pump (box 95), the fan (box 69) and the glow ignitor
(box 137) for signs of short circuiting.
step 25
Are the cables in order? Yes:
→
step
27
No:
→
step
26
step 26
Replace the cable harness (or the affected part thereof).
Replace fuse again, see box 62.
→
box
42
step 27
Turn the operating switch on the DBA control panel of the boiler to position “0” (OFF), see box 43.
step 28
Connect the power supply plug of the pump in reverse.
step 29
Turn the operating switch on the DBA control panel of the boiler to position “1” (ON), see box 55.