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7
We reserve the right to make technical modifications
Buderus Ltd. • http://www.buderus-domestic.co.uk
66
Servicing manual Gas condensing boiler Buderus 500-24/S, 500-24/C and 500-28/C • Issued 02/2006
box 232
z
Open the gas tap, see box 59.
z
Put all other gas-fired devices (e.g. gas ovens and stoves,
etc.) out of use.
z
Check to see if static gas input pressure does not rise
slowly for 2 minutes.
z
Run all other gas-fired appliances (e.g. gas ovens and
stoves, etc.) at full capacity, but do not operate the boiler.
z
The static gas input pressure must be:
for
natural gas
minimum 20 mbar and
for
propane
minimum 37 mbar.
z
Open the gas cock and place the boiler into service mode,
see box 59, 54, 55 or 13.
z
Press the service button “
A
" twice.
z
Capacity during service mode is at "
C
"
[hi]
= 100 %
(max. heating capacity).
z
Wait for 1 minute, until the boiler starts at full load.
z
Measure the working gas pressure at the appliance.
z
Measure the difference between the static and working
gas input pressure.
The working pressure may be:
for
natural gas
minimum 17 mbar and
for
propane
minimum 30 mbar.
z
Take the boiler out of operation and close the gas tap, see
box 43, 44 or 46.
z
Remove the pressure gauge.
z
Tighten the screw on the gas connection pressure
measurement nipple.
z
Open the gas tap, see box 59.
z
Use a detection product to check the gas connection
pressure measurement nipple for leaks. Use an
authorised foam-type leak detection product for this
purpose.
z
Fit the casing and place the boiler into operation,
box 233 Measure and adjust the gas/air ratio
A
DANGER OF FATAL ACCIDENT!
All work on gas pipework and gas-fitting components
must be carried out by a company registered and
authorised for this purpose.
z
Take the boiler out of operation and close the gas tap,
z
Open some of the radiator valves.
box 234
z
Reset the digital pressure gauge to zero.
A
CAUTION!
Throughout the measuring operation, keep the
pressure gauge in the same position (horizontal or
vertical) in which it was reset to zero.
z
Loosen by two turns the screw on the burner pressure
measurement nipple (item 1).
z
Connect the pressure gauge to the burner pressure
measurement nipple (item 2).
box 235
z
Open the gas cock and place the boiler into service mode,
see box 59, 54, 55 or 13.
z
Press the service button “
A
" once.
z
Capacity during service mode is at
C [lo]
= 25%
(max. heating circuit capacity).
z
Wait a short time for the boiler to be adjusted downwards.
box 236
Key to terms:
A = correct; B = false; C = turn anticlockwise;
D = turn clockwise
z
Check the gas/air ratio during service mode operation.
The differential pressure (p
gas
– p
air
)
must be –5 Pa (±5 Pa) (as indicated by the measuring
device: –10 to 0 Pa).
1
2
–15
–10
–5
0
5 (Pa)
–0,15
–0,10
–0,05
0,00
0,05 (mbar)
A
B
B
D
C
