29
GENERAL
PLEASE NOTE:
During routine servicing,
and after any maintenance or change of
part of the combustion circuit, the following
must be checked:
– The integrity of the flue system and the
flue seals.
– The integrity of the boiler combustion cir-
cuit and the relevant seals.
– The operational (working) gas inlet pres-
sure at maximum rate.
– The combustion performance as descri-
bed in 4.3.2.
4.1
D.H.W. PRODUCTION
Domestic hot water is provided via the inter-
nal storage cylinder. This cylinder is fitted
with a sacrificial magnesium anode.
The magnesium anode must be checked
regularly , at least annually and replaced
when required. Failure to replace when
required will result in internal damage to
the cylinder and void the warranty.
See section 6.15 regarding checking and
replacement of the anode.
4.2
GAS VALVE
The boiler is supplied as standard with a
gas valve, model SIT 848 SIGMA (Fig. 16).
4.3
GAS CONVERSION
(fig. 17)
This operation must be performed by
authorised personnel using original Sime
components.
To convert from natural gas to LPG or vice
versa, perform the following operations
– Close the gas cock.
– Replace the nozzle (1) and the gasket (2)
using those supplied in the conversion kit.
– Test all the gas connection using leak
detection fluid. Do not use open flames.
– Apply the nameplate with the new gas
flow layout.
– Calibrate the maximum and minimum
pressures of the gas valve following the
instructions provided in paragraph 4.3.2.
4.3.1
New fuel configuration
For access to the installer's parameters,
press simultaneously keys
and
for
5 seconds (3 fig. 12). Scroll though the
parameters using the
and
buttons.
The parameters will scroll up and down
with the keys
and
. The display pane
will show the values of the parameter PAR
1. If the boiler is a
25/55
methane (G20)
model, SET 20 will be displayed:
To change the fuel to propane (G31), it is
necessary to set SET 22, by pressing the
key .
The standard display will automatically
return after 10 seconds.
The table below shows the SET settings to
enter when the type of gas fuel is changed.
4.3.2
Calibrating the gas valve
pressures
This can only be done using a flue gas analy-
ser. If the combustion reading is greater
than the acceptable value AND the integrity
of the complete flue system and combu-
stion seals have been verified, and the inlet
gas pressure has been verified then adjust-
ments to the gas valve can be made as
described below. Make only small adjust-
ments(1/8 turn max), and allow time for
the combustion analysis to be made before
making further adjustments.
Sequence of operations:
1)
Press and hold the button down for a
few seconds
(see 4.5.1)
2)
Press the button for a few seconds
.
3)
Identify the CO
2
values at max. power by
adjusting the shutter (5 in Fig. 16):
4)
Press the button for a few seconds
.
5)
Identify the CO
2
values at min. power by
adjusting the OFF-SET regulation screw
(6 in Fig. 16):
Fig. 16
KEY
1
Upstream pressure intake
2
Intermediate pressure intake
3
Air signal inlet (VENT)
4
Downstream pressure intake
5
Capacity step
6
OFF-SET
4
USE COMMISSIONING, AND MAINTENANCE
2
1
Fig. 17
MAX power
CO
2
(Methane)
CO
2
(Propane)
9,0 ±0,3
10,0 ±0,3
MIN power
CO
2
(Methane)
CO
2
(Propane)
9,0 ±0,3
10,0 ±0,3
1
2
3
4
5
6
GAS MODELS
PAR 1
-
1
-
2
-
-
3
-
4
-
5
METHANE
25/55
20
(G20)
30/55
21
PROPANE
25/55
22
(G31)
30/55
23
-
24
-
-
25
-
-
30
