Buderus Logamax plus GB162-80 kW Service Instructions Manual page 18

4 Operation
section 24
Step 22 Is there a current heat demand from the room or external temperature-dependent controller?
Step 23 Is the current heating-system supply temperature lower than 45 °F (7 °C)?
Step 24 The pump is run for 10 seconds in order to prevent it from seizing up.
Step 25 Have ten seconds elapsed?
Step 26 Is there a DHW heating system which has generated a demand?
Step 27 Is there a current heat demand from the room or external temperature-dependent controller?
Step 28 Is the current heating-system supply temperature lower than 45 °F (7 °C)?
Step 29 The LED "DHW demand" on the control panel (section 1, [4]) lights up.
[0/c/\|
Step 30 Operating code. The boiler prepares for a burner start-up whenever a heat demand arises. The fan unit
(section 1, [20]) and the pump are started. The glow ignitor (section 1, [27]) is activated.
[0/l/\|
Step 31 Operating code. The gas valve (section 1, [21]) is activated.
See also section 29 "Display codes and other symptoms", page 21.
Step 32 Maximum four ignition attempts are carried out. Does the ionization current exceed 1.4 microamperes within these
4 ignition attempts?
[-/h/\|
Step 33 Operating code: The device is in DHW mode.
See also section 29 "Display codes and other symptoms", page 21.
The LED "Burner operation" on the control panel (section 1, [4]) lights up. The startup load on the boiler is approx.
50 % for the purposes of flow monitoring and is then modulated up or down. The degree of modulation of the pump
will hardly vary during DHW mode; the pump will be running almost continuously at 100 %.
Step 34 Is there still a heat demand?
Step 35 Is the heating-system supply temperature 45 °F (25 °C) higher than the preset DHW temperature or higher than
200 °F (93 °C)?
[0/y/\|
Step 36 Operating code: The supply temperature sensor has measured a current heating supply temperature
higher than the supply temperature setting on the control panel (section 1, [4]), or higher than the
supply temperature calculated according to the heating curve or higher than the supply temperature
calculated according to the DHW mode.
Step 37 The LED "Burner operation" is extinguished.
Step 38 The fan unit (section 1, [20]) continues to run for max. 30 seconds.
Step 39 Has the heating system supply temperature fallen sufficiently?
Step 40 The gas valve (section 1, [21]) is closed and the burner is shut down.
Step 41 The LED "Burner operation" is extinguished.
Step 42 The LED "DHW demand" is extinguished.
[0/h/\|
Step 43 Operating code. The boiler is in standby mode. There is no current heat demand.
Start of pump over-run time via the tank for a period of approx. 60 seconds.
Start of air-side purging phase of the fan unit (section 1, [20]) for approx. 30 seconds.
See also section 29 "Display codes and other symptoms", page 21.
Step 44 Have approx. 30 seconds elapsed?
18
DHW operating phase
Logamax plus GB162-80 kW/100 kW - Subject to modifications resulting from technical improvements!
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Yes: Step 48
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No: Step 23
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Yes: Step 65
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No: Step 20
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Yes: Step 19
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No: Step 26
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Yes: Step 29
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No: Step 27
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Yes: Step 48
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No: Step 28
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Yes: Step 65
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No: Step 25
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Yes: Step 33
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No: Step 12
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Yes: Step 35
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No: Step 40
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Yes: Step 36
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No: Step 33
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Yes: Step 29
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No: Step 39
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Yes: Step 45
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No: Step 44