Worcester CDi Combi N.G Service Booklet page 53

Heating up of last radiators in system too slow
Check
1. Pump map/pump step incorrect?
Flue gas levels incorrect, CO level too high
Check
1. Does the gas supply type match the
specifications on the appliance type
plate?
2. B Test gas supply pressure - OK?
Does pressure match figure
specified in installation
instructions?
3. Problem with flue?
B Check CO level in combustion air
2
in the flue (with outer casing
fitted).
Is CO level above 0.2%?
2
4. Flue gas CO levels measured at
2
min. and max. load do not match
specified levels?
B Measure the CO
5. Gas rate too high when CO
correctly set.
6.
8 716 115 748 (2009/09)
Supplied By www.heating spares.co Tel. 0161 620 6677
yes:
no:
yes:
no:
yes:
no:
yes:
no:
or O level.
2 2
level yes:
2
no:
Action
Wall hung combi and system appliances:
B Set appropriate pump map/pump step (service
function 1.C/1.d).
Conventional appliances:
B Set appropriate pump velocity on pump.
Action
go to 2
B Convert appliance to correct gas type.
Flue gas levels incorrect? go to 2
↓3.
B De-commission appliance.
Natural gas models:
B Notify gas utility.
There is flue gas in the combustion air.
B Check flue and repair or replace if necessary.
Flue gas levels incorrect? go to 4
go to 4
B Adjust CO level as per installation instructions.
2
Flue gas levels incorrect? go to 5
go to 5
B Reduce gas rate by means of adjusting screw on gas
valve and/or gas flow restrictor.
B Check CO adjustment.
2
Flue gas levels incorrect? go to 6
go to 6
B Switch OFF the appliance.
B Turn off gas valve.
B Change the gas valve.
B Open the gas valve.
B Switch ON the appliance.
B Check appliance for leaks.
RECTIFYING FAULTS
53