Buderus 500 - 24/C, Servicing Manual

Page: 16 / 80

Function 4
We reserve the right to make technical modifications Buderus Ltd. • http://www.buderus-domestic.co.uk
16 Servicing manual Gas condensing boiler Buderus 500-24/S, 500-24/C and 500-28/C • Issued 02/2006
step 49
Does the ionisation current exceed 1.4 µA (microamperes)) within 5 seconds? Yes:
→
step
50
No:
→
step
72
step 50
[-h]
The boiler is in heating mode. The symbol
G
lights up.
The startup load on the boiler is 49% for the first 13 seconds for the purposes of flow monitoring.
It is then increased or decreased.
step 51
Is there a heating requirement from the (room) temperature controller? Yes:
→
step
52
No:
→
step
57
step 52
Is the heat system flow temperature 6 °C higher than the target setting?
(The target setting is entered at the DBA control panel if room-temperature adjustment is required)
Yes:
→
step
53
No:
→
step
50
step 53
C [0y]
The gas valve is closed and the burner is shut down.
step 54
The symbol
G
goes out.
step 55
The fan stops.
step 56
Is the CH flow temperature
≥
6 °C lower than the target setting? Yes:
→
step
47
No:
→
step
53
step 57
The symbol “
K
“ goes out.
step 58
C [0h]
The gas valve is closed and the burner is shut down.
step 59
The symbol ”
G
“ goes out.
step 60
Start of pump over-run time via the heating system. The pump over-run time via the heating system is 5 minutes.
Start of the post purge phase of fan (10 seconds).
step 61
The fan stops.
→
step
13
step 62
The symbol “
K
“ lights up.
step 63
C [0c]
The fan starts up. The pump is started up.
The glow ignitor is activated for seven seconds.
step 64
C [0l]
Ignition phase: The gas valve is opened.
step 65
Does the ionisation current exceed 1.4 µA (microamperes) within 5 seconds? Yes:
→
step
66
No:
→
box 36
step 66
C [-h]
The symbol ”
G
“ lights up. The boiler is in heating mode.
step 67
Is the current CH flow temperature higher than 15 °C? Yes:
→
step
68
No:
→
step
67
step 68
The symbol “
K
goes out.
step 69
C [0h]
The gas valve is closed. The burner is shut down. The symbol
G
goes out.
step 70
Start of pump over-run time via the heating system. The pump over-run time via the heating system is 5 minutes.
Start of the post purge phase of fan (10 seconds).
step 71
The fan stops.
→
step
13
box 15 Boiler Functions