Buderus 500 - 28/C Servicing Manual page 15

box 15 Boiler Functions
step 22 Is the current CH flow temperature lower than 7 °C (frost protection)?
step 23 The pump is run for 10 seconds in order to prevent it from seizing up.
step 24 Have 10 seconds elapsed?
step 25 Is the plate heat exchanger triggered and/or is the temperature in the external storage-type water heater at least
5 °C below the temperature set at the DBA control panel?
step 26 Is there a current heat requirement from the (room) temperature controller?
step 27 Is the current CH flow temperature lower than 7 °C (frost protection)?
H
step 28 The symbol " " or "
C [0c]
The fan runs at 49 % of capacity.
step 29
The 3-way valve turns to the hot water setting for two seconds.
The glow ignitor is activated for two seconds.
C [0l]
Ignition phase: The gas valve is opened. The glow ignitor is activated for one second, followed by
step 30
alternating half-second periods of inactivity and activity until five seconds have elapsed.
step 31 Does the ionisation current exceed 1.4 µA (microamperes) within 5 seconds?
C [=h]
The boiler is in hot water mode. If there has been a power cut: The startup load on the boiler is 49%
step 32
for the first 13 seconds for the purposes of flow monitoring. It is then increased or decreased accordingly. The
G
symbol " " lights up.
step 33 Is the temperature in the plate heat exchanger higher than the temperature entered via the DBA control panel? Yes:
step 34 Is the CH flow temperature 46 °C higher than the preset DHW temperature and/or higher than 93 °C?
C [0y]
The gas valve is closed and the burner is shut down.
step 35
G
step 36 The symbol " " goes out.
step 37 The fan stops after 30 seconds.
step 38 Is the CH flow temperature lower than the preset DHW temperature plus 35°C?
step 39 The gas valve is closed and the burner is shut down.
G
step 40 The symbol goes out.
step 41 Start of pump over-run time via the cylinder.
Start of pre purge phase (10 seconds).
step 42 The fan stops.
C [0h]
The pump stops.
step 43
step 44 The 3-way valve turns to the heating mode setting for two seconds.
H
The symbol " " or "
step 45 Is there a current heat requirement from the (room) temperature controller?
K
step 46 The symbol lights up.
C [0c]
The fan runs at 49 % of capacity. The pump is started up.
step 47
The glow ignitor is activated for seven seconds.
C [0l]
Ignition phase: The gas valve is opened.
step 48
We reserve the right to make technical modifications
Servicing manual Gas condensing boiler Buderus 500-24/S, 500-24/C and 500-28/C • Issued 02/2006
I
" for hot water mode on the DBA control panel display lights up.
I
" goes out.
Function
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Yes:
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No:
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No:
Buderus Ltd. • http://www.buderus-domestic.co.uk
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step 62
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step 23
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step 18
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step 25
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step 28
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step 26
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step 46
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step 27
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step 62
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step 24
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step 32
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step 72
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step 39
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step 34
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step 35
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step 32
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step 29
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step 38
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step 46
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step 19
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