28
- Turn control thermostat 4 up to its maximum
setting.
- Now the main burner should turn on. With
leak detection fluid test for gas soundness
of all gas components and joints.
- See paragraph 6.13 for regulating the
heating circuit thermostat.
Check gas mains pressure (fig. 39). Fit a
gas pressure gauge on pressure inlet 77
(fig. 38) on the gas valve, after releasing
the seal screw.
Check the gas mains pressure with the
boiler operating.
Check with the Local Gas supplier if the
pressure differs significantly from 20 mbar
(natural gas), 37 mbar (G 31) and 29 mbar
(G 30).
6.8
CHECK THE GAS PRESSURE AT THE
BURNER
Now check if the maximum gas pressure at
the burner is equal to 10.5 ± 0.5 mbar (4.2
± 0.2 in w.g.) for CSI 85 - CSI 85T.
– LPG check gas pressure inlet (37 mbar
propane - 29 mbar butane). To do this proceed
as follows:
- Turn off main switch 1 (fig. 37)
- Set main switch 1 on
- Set control thermostat 5 at it maximum
setting.
- Fit a pressure gauge, using a hose, to
pressure test point 81 (fig. 38), after
first loosening its close-off screw.
- Open one or more hot water taps so that at
least 10-12 litre of water flows per minute.
- The pressure indicated on the pressure
gauge is the maximum operating gas
pressure.
-
Check that the minimum pressure
corresponds to 2 mbar (0.8 in w.g.) for G
20 as is set at the factory.
- LPG 7.3 mbar for G 31 and 7.0 mbar for G
30.
This is set and sealed at the factory
and cannot be adjusted.
Detach one of the wires going to modulator
104 (Fig. 38) and make the boiler operate as
done for checking the maximum pressure.
6.9 ADJUSTING
MINIMUM
AND
MAXIMUM
PRESSURE (fig. 36)
SIT-HONEYWELL-DUNGS GAS VALVE
- Remove cap covering modulator to gas
valve.
- Detach one of the cables connected to the
modulator 114.
- With the boiler operating use a screw
driver (HONEYWELL 9 mm spanner) to
turn the nut 111 clockwise to increase
pressure and anti-clockwise to decrease
pressure.
NOTE: LPG ONLY
The minimum pressure is factory set and
sealed, and cannot be adjusted.
6.10
RECONNECT THE DETACHED CABLE
Use a screw-driver to hold nut 111
(HONEYWELL 9 mm spanner) and use a 10
mm spanner (HONEYWELL 7 mm spanner)
wrench to rotate the nut 110 clockwise to
increase the pressure and counter-clockwise
to decrease it. After adjustment turnoff D.H.W.
Taps.
6.11 SETTING CENTRAL HEATING GAS
PRESSURE THE BOILER COMES SET
AT MID POSITION RATING FOR USE ON
C.H. (table1)
When the boiler operates in the C.H. mode
the gas pressure at the burner can be set
between the min and max values. This
permits capacity to be adjusted to suit system
demand. If adjustment is required proceed as
follows:
- Remove the front panel and the panel
instrument as described (sect. 5.4).
- Unscrew the two screws holding the
control box cover and lift off.
- Select summer/winter switch in winter
position (Fig. 37).
- Turn CH control knob to maximum
setting (fig. 37 item 4).
- Check all external controls are on and
calling for heat, ensure all D.H W. taps are off.
- With boiler operating use a screwdriver to
turn potentiometer (fig. 36) clockwise to
increase pressure and anti-clockwise to
decrease pressure.
- To obtain the desired heat value establish
pressure as per (fig. 39).
- Replace the protective cover.
- Once this pressure is established, mark
it up on data badge with, adhesive red
label/arrow burner pressure setting so that
this can be referred to and checked during
future servicing.
28
Summary of Contents for 780 Series
Page 2: ......
Page 7: ...7 Fig 3 OVERALL DIMENSION ...
Page 34: ...34 Fig 45 Fig 44 Fig 46 ...
Page 36: ...36 Fig 48 Fig 47 Fig 49 Fig 50 Fig 51 ...
Page 42: ...Fig 59 42 SECTION 9 ELECTRICAL SYSTEM DIAGRAM ...
Page 46: ...79 83 105 46 50 27 16 39 17 2 22 100 1 4 5 11 8 SECTION 11 ...
Page 49: ...49 ...
Page 50: ...COD 0017LIB06010 2 03 2010 ...
