Use And Maintenance; Gas Valve Adjustment - Sime RS Mk.II Instructions Pour L'utilisateur

4

USE AND MAINTENANCE

4. 1 GAS VALVE
Boilers are normally produced with a
HONEYWELL V4085 gas valve (fig. 19).
NOTE:
The seal on the slow opening control
(accelerator 5) must not be tampe-
red with in any way or the valve gua-
rantee will be nullified.
4. 1 . 1 Rectified connector
The electrical command on valve
V4085 is supplied by a rectified con-
nector (code 6243600), which must
be replaced if it is broken. Follow the
instructions in fig. 20 to replace it.
4.2

GAS VALVE ADJUSTMENT

"RS Mk.II" boilers have a gas valve with
a coil assembly which permits power to
be reduced by about 40% of the rated
power level before the burner goes out
all the way through a control thermo-
stat with dual contacts. SIME sets the
maximum pressure setting and the
reduced pressure setting on the pro-
duction line, and these settings should
not be changed except in the case of
change to another type of gas (butane
or propane), in which case they may be
changed complying with the values
shown in Table 3.
This operation must be performed
exclusively by authorised service
technicians, or the guarantee will be
nullified.
Operations involved in adjustment of
pressure settings must be carried out
in a certain order, adjusting the maxi-
mum pressure first and then the redu-
ced pressure.
4.2. 1 Adjusting maximum
and minimum pressure
Proceed as follows to set the maxi-
mum pressure (fig. 21):
– Connect the column or pressure
gauge to the pressure intake on the
burner manifold.
– Slacken screw (4) all the way.
– Set the thermostat knob to the maxi-
mum value.
– Turn on the power supply to the
boiler.
– Slacken lock nut (1) and turn union
(3): turn the union anti-clockwise to
reduce pressure, or clockwise to
increase it.
KEY
1 Electrical control
2 Coil
3 Pressure intake
4 Connection flange
5 Slow opening control
(accelerator)
TABLE 3
Type of gas Reduced burner pressure
Methane - G20
Butane - G30
Propane - G31
KEY
1 Electrical control
2 Rectified connector
– Tighten lock nut (1).
– Turn on the main switch repeatedly,
checking that pressure corresponds
to the values specified in Table 3.
After setting maximum pressure, set
minimum pressure as follows (fig. 21):
– Once again, use the column or a
pressure gauge to read pressure.
– Turn off the power supply to the
coil (2)
– Turn on the boiler and allow it to ope-
rate at rated power for a short time,
then slowly turn the thermostat
knob down until you hear the first
thermostat contact trip.
– Leave the thermostat knob in this
position and turn the screw (4) to
find the reduced pressure value spe-
cified in Table 3 for the type of gas in
use; turn screw (4) anti-clockwise to
decrease pressure or clockwise to
increase pressure.
– Restore the power supply to the coil.
Max. burner pressure
mbar
6
15
15
– Turn on the main switch repeatedly,
checking that pressure corresponds
to the specified value.
KEY
1 M13 lock nut
2 Coil
3 Maximum pressure
control union
4 Reduced pressure
control screw
Fig. 19
mbar
9,7
28
35
Fig. 20
Fig. 21
69