Air/Gas Mixture Adjustment; Propane Gas Models - andrews ECOflo EC230/600 Installation Manual, Operation And Maintenance Manual

34
SECTION 4 • COMMISSIONING

AIR/GAS MIXTURE ADJUSTMENT

The water heater gas/air mixture is adjusted at the factory
for the proper mixture for optimum combustion and
ignition for the type of gas listed on the rating label. The
water heater should operate properly without requiring
adjustment with the gas type shown on the rating label.
The following is a guide for the correct mixture adjustment
settings in case the gas content is different from the rating
label or ignition is not satisfactory. A combustion analyser
is necessary for making gas/air mixture adjustments to
determine the correct setting.
The water heater cannot be converted from natural to L.P.
gas or L.P. gas to natural gas, without changing the gas
valve/venturi assembly. Using L.P. gas on a water heater
set up for natural gas will result in rough ignitions and
dangerous levels of carbon monoxide.
Do not attempt to adjust the venturi screws without a
properly calibrated CO²/CO combustion analyser. Making
the mixture richer without an analyser to monitor the
adjustments can result in dangerous levels of carbon
monoxide.
Fig. 13
G20 (NATURAL GAS, MOSTLY METHANE)
FAMILY
The venturi screw depth, when measured with a set of
callipers (see fig. 13), should be approximately 13.0 –
13.5mm. The CO² range should be set as detailed in
Table 1.
The CO content should be less than 50ppm.
If the CO² content is above the correct percentage, turn
the venturi screw (see fig. 14), clockwise half a turn and
recheck combustion. Repeat, if necessary, until the
correct reading is achieved. Turn the venturi screw anti-
clockwise if the CO² reading is less than the stated figure
or the ignitions are not smooth.

PROPANE GAS MODELS

The burner assembly is factory adjusted for Propane Gas
on LPG models. The nominal venturi screw setting is the
same as G20 Natural Gas, i.e. 13.0 – 13.5mm screw
depth. A gas inlet orifice is used on LPG models to use
the same venturi screw setting. The CO² range for
propane should be set as shown in Table 1, and
adjustment carried out as detailed above. The CO
content should be less than 50ppm.
Measurement of
venturi screw depth
with vernier calipers.