Benchmark ZWB 7-29 CC1 Installation And Servicing page 90

Failure identification procedure
3.4 Faults that are not displayed
3.4.1 Appliance faults
Excessive burner noise, rumbling noises
Check
1. Does the gas supply type match the
specifications on the appliance iden-
tification plate?
B Test gas supply pressure - OK?
2.
Does pressure match figure speci-
fied in installation instructions?
3. Problem with flue?
B Check CO
level in combustion
2
air.
Is CO level above 0,2 % ?
2
4. Cascade system:
Is the appliance min. output high
enough to open the shut-off device?
5. Is appliance's internal air/flue chan-
nel leaking or blocked?
B Open up heat exchanger and
inspect.
B Remove silencer, flue duct and air
flow limit.
B Open trap and inspect.
Air channels dirty/clogged, seals
defective or not correctly fitted?
B Measure CO
6.
2
CO levels in flue gas at min and
2
max output do not match figures
specified in installation instruc-
tions.
42
yes:
no:
yes:
no:
yes:
no:
yes:
no:
yes:
no:
levels. yes:
no:
Action
B Note the setting of the temperature controls
and .
↓2.
B Convert appliance to correct gas type.
↓2.
↓3.
B Decommission appliance.
For natural gas:
B Notify gas company.
B Check flue and repair or replace if necessary.
↓3.
↓5.
B Press buttons
and
B Select Service Function 5.5 .
B Increase min. output.
B Repair or replace components.
B Grease seal before fitting.
B Make sure it is fitted in correct position.
↓6.
B Adjust CO
level as per installation instructions.
2
B Turn off gas cock.
B Power OFF the appliance.
B Change the gas valve.
B Open the gas cock.
B Turn ON the appliance.
B Check appliance for leaks.
simultaneously.
7 181 465 346 GB (03.02)