Sime Format.zip 5 25 OF Para El Instalador página 89

4.5. 1 Adjusting valve pressure
Set maximum and minimum pressure on
gas valves as follows (fig. 22/a):
– Connect the column or a manometer to
the intake downstream of the gas valve.
In "25 BF TS" models, disconnect the
valve VENT pressure test point tube (5
fig. 21).
– 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 to the maximum pres-
sure 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
/nut (2) to the minimum pressure indi-
cated 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-
sure test point.
– Put the plastic cap (1) back on the modu-
lator and seal with a drop of coloured
sealant if necessary.
4.6 DISMANTLING THE CASING
The casing may be removed completely to
facilitate boiler maintenance, as shown in
fig. 23.
4.7 CLEANING AND MAINTENANCE
Carry out the cleaning of the generator in
the following way:
– Turn the main switch off to stop electric
power reaching the boiler and close the
gas feed cock.
– Remove the outer casing and the gas
burner manifold unit . To clean the bur-
ner, blow in a jet of air, so as to remove
any dust particles that may have accu-
mulated.
– Clean the heat exchanger, removing any
dust or residue from combustion. When
cleaning the heat exchanger or the bur-
ners, chemical products or steel bru-
SIT 845 SIGMA
1
3
2
KEY
1 Plastic tap
2 Minimum pressure adjusting nut
3 Maximum pressure adjusting nut
1
HONEYWELL VK 4105M
SIEMENS VGU 50
Fig. 22/a
2
Fig. 23
IT
ES
PT
ENG
89