Sime Format System 25 HE Installation And Servicing Instructions page 16

clockwise; to reduce it turn the screw
anti-clockwise.
6) Adjust gas capacity step (7) in order to
achieve a C0 value of 8.9% for natural
2
gas or of 9.8% for propane. To reduce
C0 value, turn the screw clockwise.
2
7) Go to maximum power by turning
clockwise trimmer (6) as far as it will
go.
8) Adjust the trimmer (2) and check that
the Hertz value of the fan is between
172 and 176.
9) Check that C0 value is approx. 9.0%
2
for natural gas or 10.0% for propane. In
case the value would not be correct,
repeat calibration procedure as men-
tioned in point 4.
4.5 CALIBRATION PROCEDURE
IN HEATING PHASE
USING MBAR
1) Adjust air pressure (fan speed)
Connect the positive of the manometer to
the positive test point of sealed chamber (7
fig. 3). Disconnect the SM sensor and con-
nect a loose one free in air, or activate the
chimney sweep function.
Sequence (Fig. 20)
- Turn the heating output potentiometer to
maximum output.
- Turn the heating output trimmer B to mini-
mum.
- Adjust the minimum air pressure using
fan speed trimmer A.
- Fully open a domestic hot water tap.
AIR PRESSURE
Minimum
(mm H O)
2
12.5/13.5
- Adjust the maximum air pressure using
fan speed trimmer D (2 fig. 20).
2) Adjust gas pressure
Connect the positive of the manometer to
the gas test point (6 fig. 3).
Sequence (Fig. 20)
- Turn heating output potentiometer to
maximum output.
- Turn the heating power trimmer B to mini-
mum.
- Adjust the minimum gas pressure using
the OFF-SET (8) on the gas valve.
- Fully open a domestic hot water tap.
GAS PRESSURE
Minimum
(mm H O)
2
10.5/11.5
CO VALUE %
2
Natural gas
Minimum output 8.7/9.3
Maximum output 8.7/9.3
- To adjust CO at maximum output adjust the
2
gas valve OFF-SET.
- To adjust CO at minimum output to ajust the
2
gas valve shutter.
14
KEY
2
4
6
7
8
- Adjust the maximum gas pressure using
the gas valve shutter (7).
Very important: It's not necessary to adjust
the gas pressure or the fan speed should
the boiler be converted to another gas (ie
natural gas to LPG) only the injector will
require changing.
Maximum
(mm H O)
2
76/78
4.6 DISASSEMBLY OF
EXPANSION VESSEL
To disassemble the expansion vessel, pro-
ceed as follows:
– Make sure that the water has been emp-
Maximum
(mm H O)
2
65/67
LPG
9.7/10.3
9.7/10.3
MAX fan speed trimmer
MIN fan speed trimmer
Heating power trimmer
Shutter
OFF-SET
7
1
2
6 4
8
tied out of the boiler.
– Unscrew the connection and the locknut.
– Remove the expansion vessel.
Before refilling the system, using a pres-
sure gauge attached to the valve make sure
that the expansion vessel is preloaded at a
pressure of 0.8 to 1 bar.
4.7 REMOVAL OF OUTER
CASING
It is possible to completely disassemble the
shell for an easy maintenance of the boiler
as showed in fig. 21.
2
Fig. 20
Fig. 21