Buderus 500 - 28/C Servicing Manual page 66

7 Actions
box 232
Open the gas tap, see box 59.
Put all other gas-fired devices (e.g. gas ovens and stoves,
etc.) out of use.
Check to see if static gas input pressure does not rise
slowly for 2 minutes.
Run all other gas-fired appliances (e.g. gas ovens and
stoves, etc.) at full capacity, but do not operate the boiler.
The static gas input pressure must be:
for natural gas minimum 20 mbar and
for propane minimum 37 mbar.
Open the gas cock and place the boiler into service mode,
see box 59, 54, 55 or 13.
Press the service button "A" twice.
Capacity during service mode is at "C" [hi] = 100 %
(max. heating capacity).
Wait for 1 minute, until the boiler starts at full load.
Measure the working gas pressure at the appliance.
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.
Take the boiler out of operation and close the gas tap, see
box 43, 44 or 46.
Remove the pressure gauge.
Tighten the screw on the gas connection pressure
measurement nipple.
Open the gas tap, see box 59.
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.
Fit the casing and place the boiler into operation,
see box 51, 54 or 55.
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.
Take the boiler out of operation and close the gas tap,
see box 43, 44, 46 or 47.
Open some of the radiator valves.
We reserve the right to make technical modifications
66 Servicing manual Gas condensing boiler Buderus 500-24/S, 500-24/C and 500-28/C • Issued 02/2006
box 234
1
A
Reset the digital pressure gauge to zero.
CAUTION!
Throughout the measuring operation, keep the
pressure gauge in the same position (horizontal or
vertical) in which it was reset to zero.
Loosen by two turns the screw on the burner pressure
measurement nipple (item 1).
Connect the pressure gauge to the burner pressure
measurement nipple (item 2).
box 235
Open the gas cock and place the boiler into service mode,
see box 59, 54, 55 or 13.
Press the service button "A" once.
Capacity during service mode is at C [lo] = 25%
(max. heating circuit capacity).
Wait a short time for the boiler to be adjusted downwards.
box 236
B
–15 –10
–0,15 –0,10
C
Key to terms:
A = correct; B = false; C = turn anticlockwise;
D = turn clockwise
Check the gas/air ratio during service mode operation.
The differential pressure (p
must be –5 Pa (±5 Pa) (as indicated by the measuring
device: –10 to 0 Pa).
Buderus Ltd. • http://www.buderus-domestic.co.uk
A B
–5 0 5 (Pa)
–0,05 0,00 0,05 (mbar)
D
– p )
gas air
2