Sime RX Series - Safety Stat; Use and Maintenance; Adjusting Gas Valve (19-55 Versions)

4.1 ADJUSTING GAS VALVE
“19÷55” VERSIONS
Standard “RX 19÷55 CE” and “RX 19-
26 PVA CE” boilers feature a
HONEYWELL V4600C gas valve (fig.
8). When the boiler is ignited for the
first time, it is always better to purge
the pipe by using the inlet pressure tap
(6) on the gas valve.
The pilot burner gas flow rate shall be
adjusted on the screw (4): to decrease
the pilot flame rotate the screw
clockwise; to increase the pilot flame
rotate the screw anticlockwise.
To adjust the main burner gas pressu-
re remove the plug on the pressure
regulator (2). The regulation is made
by rotating the screw under the plastic
plug with a screwdriver: rotate the
nylon screw anticlockwise to reduce
the pressure, clockwise to increase it.
51
3.3 SAFETY STAT
In case the boiler temperature
exceeds 95°C the safety stat (6-14 fig.
2), will extinguish the pilot burner thus
shutting off the gas flow to the pilot
and main burner.
“RX 19-26” models are equipped with
safety stat with automatic resetting,
and “RX 37÷55” with manual reset-
ting. Should the stat with manual reset-
ting trip off, it will be necessary to
unscrew the cover and reset the but-
ton below for the pilot burner to
restart.
3.4 CIRCULATING PUMP
PERFORMANCE CURVES
The “RX PVA” boilers can be equipped
with either EURAMO NYL 40/25 or
GRUNDFOS UPS 25/50 circulating
pumps.
Both have a built-in speed selector for
adjusting head and capacity.
Head and capacity performance cur-
ves of the standard circulating pump,
at different speeds, are given in fig. 7.
NOTE: Before starting the boiler
check that the circulating pump is
not locked.
0
0,5
4
3,532,521, 51
Q (m
3
/h)
5
4
1
2
3
H (m)
1
2
3
EURAMO NYL 40/25
GRUNDFOS UPS 25/50
Fig. 7 Fig. 7/a
4 USE AND MAINTENANCE
KEY
1 Control button
2 Pressure regulator
3 Electric operator
4 Pilot burner adjusting screw
5 Outlet pressure tap
6 Inlet pressure tap
ON
OFF
Fig. 8