Function
4
We reserve the right to make technical modifications
Buderus Ltd. • http://www.buderus-domestic.co.uk
14
Servicing manual Gas condensing boiler Buderus 500-24/S, 500-24/C and 500-28/C • Issued 02/2006
4
Function
box 15
Boiler Functions
Start phase
step 1
Turn the mains switch to “ON”.
step 2
Turn the operating switch on the DBA control panel of the boiler to position “
1
“ (ON) – see also box 11.
step 3
Is a 3-way valve fitted?
Yes:
→
step
4
No:
→
step
6
step 4
Is the 3-way valve set to “hot water mode”?
Yes:
→
step
5
No:
→
step
6
step 5
The Buderus 24V AC external 3-way valve is turned to “heating mode” in 7.5 seconds, while an internal 3-way
valve is turned to “heating mode” in 2 seconds.
step 6
,00{
The display on the DBA control panel of the boiler is checked (maximum of one second).
step 7
[24]
Current CH flow temperature, in °C. See also box 20.
step 8
C [0u]
The boiler begins to warm up. Start of pre purge phase.
The fan runs for 15 seconds at about 60 % of maximum speed.
Checking phase
step 9
Has the pre purge been completed correctly?
Yes:
→
step
11
No:
→
step
10
step 10
Deal with fault. The error code, which is now displayed, can be found in box 20. Deal with the fault.
Operating phase
step 11
C [0h]
Operating code. See also box 20. The boiler is ready for operation.
No current heat requirement.
step 12
Start of pump over-run time via the heating system.
The pump over-run time:
– via the heating system, factory-adjusted to 5 minutes;
– via the external reservoir, set to 30-40 seconds;
– via the plate heat exchanger (ECO), set to 30-40 seconds;
– via the plate heat exchanger (warm start), set to 30 seconds;
– after service mode, 1 minute.
step 13
Has the pump over-run time expired?
Yes:
→
step
18
No:
→
step
14
step 14
Is the boiler set to warm start for hot water and/or is an external storage-type water heater connected?
Yes:
→
step
15
No:
→
step
16
step 15
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?
Yes:
→
step
28
No:
→
step
16
step 16
Is there a current heat requirement from the (room) temperature controller?
Yes:
→
step
46
No:
→
step
19
step 17
Is the current CH flow temperature lower than 7 °C (frost protection)?
Yes:
→
step
62
No:
→
step
18
step 18
The pump stops.
step 19
Has the pump been out of use for more than 24 hours?
Yes:
→
step
23
No:
→
step
20
step 20
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?
Yes:
→
step
28
No:
→
step
21
step 21
Is there a current heat requirement from the (room) temperature controller?
Yes:
→
step
46
No:
→
step
22
