Buderus 500 - 24/C, Servicing Manual

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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 35
box 37
The system has detected an ionisation current before burner startup.
Locking boiler-fault code
step 1
Is the ionisation current displayed? Yes:
→
step
2
No:
→
step
1
step 2
Disconnect the plug-and-socket connection, see box 144.
step 3
Is the ionisation current still displayed? Yes:
→
step
12
No:
→
box
41
step 4
Check the plug-and-socket connection between the ionisation electrode and cable loom, see box 144.
step 5
Is the plug-and-socket connection in full working order? Yes:
→
step
7
No:
→
step
6
step 6
Correctly insert the plug into its socket.
→
step
11
step 7
Check the cable of the ionisation electrode, see box 151.
step 8
Is the wiring in order? Yes:
→
step
10
No:
→
step
9
step 9
Replace the cable loom (or the affected part thereof).
→
step
13
step 10
Check the ionisation electrode, see box 149 or box 155.
→
box
42
step 11
Is the ionisation electrode working correctly? Yes:
→
step
14
No:
→
step
12
step 12
Replace the ionisation electrode, see box 155.
→
box
42
step 13
Switch the boiler off and then on again at the operating switch.
step 14
The following components should be checked for soiling, damage and/or correct installation:
- syphon, see box 256
- flue-gas pipework.
step 15
Check the pressure control valve, see box 85.
step 16
Is the pressure control valve working correctly? Yes:
→
box
41
No:
→
step
17
step 17
Replace or clean the pressure control valve, see box 85.
→
box
42
box 38
An ionisation current has been measured as soon as the burner shuts down.
Locking boiler-fault code
step 1
Connect a digital pressure gauge, see box 233 and 234. Open the gas cock and place the boiler into full-load
operation, see box 59 or box 13. Deactivate the heat requirement as per flue-gas test (box 13), and check to
see if the burner remains under pressure after the “heat requirement” symbol on the DBA control panel goes
out.
step 2
Is the burner still under pressure? Yes:
→
step
4
No:
→
step
3
step 3
Check the ionisation electrode, see box 37.
step 4
Close the gas cock, see box 46. Remove the digital pressure gauge and close the burner-pressure
connection nipple. Open the gas cock, see box 59, and run the boiler at full load once more, see box 59 or
box 13. Deactivate heat requirement, see box 13, and check to see if the gas valve is still powered after the
“heat requirement” indicator goes out, see box 165, item 1 and 2.
step 5
Is the gas valve still powered? Yes:
→
box
41
No:
→
step
6
step 6
Replace the gas valve, see box 174.
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