Sime Format 25, Installer'S Instructions

Page: 90 / 100

32):
– Close the gas cock.
– Disassemble the burner manifold (1).
– Replace the main nozzles (5) supplied in
a kit, inserting the copper washer (4).
Use a ø 7 spanner to perform this ope-
ration.
– Remove the “METANO/GPL” connector
link on the card and set it in the posi-
tion corresponding to the gas to be
used (4 fig. 22).
– To set the values of maximum and mini-
mum gas pressure, follow the instruc-
tions given in section 4.4.1.
– After have ultimated the conversion of
the boiler, please stick onto the casing
panel the plate showing the relevant fee-
ding gas which is included into the kit.
NOTE: When reassembling components
which you have removed, replace gas
seals; test all gas connections after
assembly using soapy water or a product
made specifically for the purpose, being
sure not to use open flame.
4.4.1 Adjusting valve pressure
Set maximum and minimum pressure on
S I T 84 5 S I G M A o r H O N E Y W E L L V K
4105M valves as follows (fig. 29):
– Connect the column or a manometer to
the intake downstream of the gas valve.
In “BF” models, disconnect the valve
VENT pressure test point tube (5 fig. 28).
– Remove the cap (1) from the modulator.
– Place the hot tap water potentiometer
knob at the maximum position.
– Turn on the boiler using the four-way
switch and turn on a hot water tap all
the way.
– Remember that rotating clockwise will
increase pressure while rotating anti-
clockwise will diminish it.
– Adjust maximum pressure using the nut
(3) with a wrench (10 for 845 SIGMA, 9
for VK4105) to the maximum pressure
value indicated in Table 4 .
– Do not adjust minimum pressure until
you have adjusted maximum pressure.
– Turn off the supply power to the modula-
tor, and keep the hot water tap turned
on.
– Lock the nut (3) in place, turn the screw
(2) for 845 SIGMA or the nut (2) using a
7 wrench for VK4105 to the minimum
pressure indicated in Table 4 .
– Turn off the boiler and turn it back on
again several times, keeping the hot
water tap turned on at all times and
checking that the maximum and mini-
mum pressure values correspond to the
established values; correct the settings if
necessary.
– Adjust, checking that you have restored
the power to the modulator.
– Put the pipe back on the valve VENT
pressure test point.
– Remove the manometer, remembering
to tighten the screw for closing the pres-
90
IT
ES
PT
GB
1
2
3
4
Fig. 27
KEY
1
Pressure inlet downstreamr
2 VENT pressure test point
3 Sealed chamber
4 Manometer
3
4
2
1
5
6
1 2
4 3 5
SIT 845 SIGMA HONEYWELL VK 4105M
KEY
1
Modulator
2 EV1-EV2 coils
3 Pressure inlet upstream
4 Pressure inlet downstream
5 VENT pressure test point
3
2
1
Fig. 29
KEY
1
Plastic tap
2 Minimum pressure adjusting nut
3 Maximum pressure adjusting nut
SIT 845 SIGMA HONEYWELL VK 4105M
TABELLA 4
Burner max. Modulator Burner min. Modulator
Type of gas pressure mbar current pressure mbar current
25/60 OF 25/60 BF 30/60 BF mA 25/60 OF 25/60 BF 30/60 BF mA
Methane (G20) 9,7 11,0 11,3 130 1,8 2,0 2,2 0
Butane (G30) 27,5 28,2 28,0 165 5,0 4,9 5,5 0
Propane (G31) 35,5 36,2 36,0 165 5,0 4,9 5,5 0
Fig. 28