Use And Maintenance; Temperature Adjustment; Gas Valve; Pressure Adjustment - Sime Format.ZIP Serie Manual De Instrucciones Para El Instalador

4

USE AND MAINTENANCE

4. 1 D.H.W. TEMPERATURE
ADJUSTMENT
The sistem with a potentiometer for adju-
sting the temperature of D.H.W. with a set-
ting range from 30° to 60°C offers a dou-
ble advantage:
1) The boiler adapts perfectly to any type of
D.H.W. system, whether the mixing
system is a mechanical or a thermostat-
controlled type.
2) The thermal output is dosed according
to the temperature required, which
means a considerable saving in fuel.
NOTE: In order to avoid any misunder-
standing please remember that the value
obtained by the product of temperature
difference (in °C) between D.H.W. output
and input into the boiler by the hourly
flow rate measured on the tap, where
hot water is drawn off (l/h), cannot be
higher than the useful output developed
by the boiler.
For measurements and checks on flow
rate and temperature of D.H.W., use sui-
table instruments, taking into considera-
tion any heat dispersion along the stret-
ch of piping between the boiler and the
measuring point.
4.2 ADJUSTMENT OF
D.H.W. FLOW RATE
To adjust the D.H.W. flow rate, use the flow
rate adjuster (5 fig. 5).
Remember that the flow rates and corre-
sponding temperatures of use of hot water,
given in section 1.3, have been obtained by
positioning the selector of the circulation
pump on the maximum value.
Should there be any reduction in the
D.H.W. flow rate, the filter installed on the
inlet to the divertor valve (3 fig. 5) will
need cleaning.
4.3

GAS VALVE

The boilers are equipped standard with the
SIT 845 SIMGA/HONEYWELL VK 4105M
gas valve (fig. 19).
The gas valve is set at two pressure values:
maximum and minimum.
According to the type of gas burnt, these
correspond to the values given in Table 4.
The gas pressures at the maximum and
minimum values, are factory set. Conse-
quently they must not be altered.
Only when you switch the appliance from
one type of gas suppl y (me t hane) t o
another (butane or propane), it is permit-
ted to alter the operating pressure.
It is essential that this operation is carried
out exclusively by authorized technical
staff. When the working pressures have
been adjusted, reseal the regulators.
When the gas pressures are to be reset,
this must be done following a set order
84
SIT 845 SIGMA
5
4
1
3
6
KEY
1 Modulator
2 EV1-EV2 coils
3
4
TABLE 4
Burner max.
Type of gas pressure
mbar
Methane (G20) 11,8 - 12,7
Butane (G30) 28,5
Propane (G31) 36,5
depending on the type of valve:
Calibrate pressures in the established order,
first setting the MAXIMUM and then the
MINIMUM.
4.3. 1

Pressure adjustment

SIT 845 SIGMA (fig. 20/a)
To set the maximum pressure, proceed as
follows :
– Connect the pressure column to the pres-
sure inlet downstream of the gas valve.
In model "BF", connect up the pressure
gauge as shown in fig. 20.
– Remove the plastic cap (1).
– Set the knob of the D.H.W. potentiome-
ter to the maximum value.
– Ignite the boiler and open the hot
HONEYWELL VK 4105M
1
2
5 3 4
3 Pressure inlet upstream
4 Pressure inlet downstream
5 VENT pressure test point
2
KEY
1
1 Pressure inlet downstreamr
2 VENT pressure test point
3 Sealed chamber
4 Manometer
Modulator Burner min.
current
mA
130
165
165
water cock.
– Using a ø 10 spanner, turn the nut (3)
to arrive at the maximum pressure
1
2
KEY
1 Plastic tap
2 Minimum pressure
adjusting screw
3 Maximum pressure
adjusting nut
2
Fig. 19
Fig. 20
Modulator
pressure current
mbar mA
2,4 - 2,6 0
5,9 - 5,5 0
7,7 - 7, 1 0
3
Fig. 20/a