Product specifications

4. Carbon monoxide : carbon dioxide ratio
Atmos recommends that a carbon dioxide : carbon
monoxide ratio test is carried out each time the
boiler is serviced. This is best done after the O
2
and
the CO
2
content of the flue gasses has been
measured and the gas valve regulator adjusted.
Measure the CO/CO
2
ratio first with the burner set
at the low rate (LL) and then again with the burner
set at the high rate (HH).
The CO/CO2 ratio at low or high burner rate
should be no higher than 0.004.
A CO/CO2 ratio between 0.004 and 0.008 means
that the appliance is ‘At Risk’ (AR).
A CO/CO2 ratio above 0.008 means that the
appliance is ‘Immediately Dangerous’ (ID)
Where an ‘at risk’ or ‘immediately dangerous’
situation is encountered, measures must be
undertaken to rectify the situation. Particular
attention should be given to the gas/air ratio, the
integrity of the flue, or blockage in the heat
exchanger. Contact the manufacturer for
assistance.
Replace the dust cap and the flue gas test cap when
finished. Record the data on the Service card.
ATMOS MULTI Mk 2 version 2008
Page 40