Roca CRONO 4-G COMPACT Instructions D'installation page 22

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GAS TRAIN PRESSURE LOSS
The gas train pressure loss ∆p is provided from the
°
diagram; the scales of the volumetric output are
V
valid respectively for:
a = air,
n = natural gas (G20),
p = propane (G30),
c = city gas (G140), only for applications not covered
by the Gas Appliances Directive (90/396/EEC).
The minimum necessary pressure in the network
can be obtained by adding the pressure of the dia-
gram to the burner pressure losses and the back
pressure of the combustion chamber (see the tech-
nical instruction of the heat generator).
VALVE ADJUSTMENTS
The slow firing delivery (valve opening phase) must
be regulated by turning the screw (10, fig. 5 page 6)
anticlockwise to increase delivery and clockwise to
reduce it.
The amount of gas at start-up can be adjusted to as
much as 80% of main delivery.
Main delivery is reached progressively starting from
the firing delivery. It is achieved by turning the screw
(11, fig. 5 page 6) clockwise to increase delivery and
anticlockwise to reduce it.
Hence, turn the screw (11) anticlockwise until you
hear a slight "click" then turn it clockwise to the
desired pressure / delivery. This is an initial setting
and will require correcting later depending on required
thermal power.
D4574
LOW GAS PRESSURE SWITCH ADJUSTMENT
Adjust the gas pressure switch (6, fig. 5 page 6) after carrying out all the other adjustments of the burner
with the gas pressure switch adjusted at the beginning of the scale.
Let the burner work at the required output. Slowly start to close the gas isolation valve on the gas supply
manifold reducing the pressure by 5 - 6 mbar from that recorded as the normal working gas pressure
measured on your pressure gauge.
Rotate the dial on the pressure switch until the dial reads just below the reduced value now showing on
your pressure gauge, the burner should shut down.
Open op the isolation valve and check that the burner starts and runs correctly.
GAS PRESSURE (M3, fig. 5 page 6)
The gas head pressure is measured at the pressure test point (M3).
AIR DAMPER ADJUSTMENT
The air is adjusted by turning the screw (3, fig. 8 page 9).
3217
7
GB