23
7. Continue to fill the system until the
pressure gauge indicates between
0.5 and 1.0 bar. Close the fill point
valve.
8. Repeat steps 4 and 5 as required.
9. Close the fill point and double check
valves either side of the filling loop
and disconnect the loop.
7.4 Vent the Pump
It is important that the pump is properly
vented to avoid it running dry and damaging
its bearings. To gain access to the pump
for venting it is necessary to remove the
control panel. The procedure is as follows:
1. Loosen the four fixing screws
securing the panel to the casing,
push the panel towards the rear of
the boiler and lower the control panel
to expose the pump.
2. Remove the cap, then unscrew and
remove the plug from the centre of
the pump.
Sealed Systems
SYSTEM PRESSURE
15-26-S PRO UTILITY SYSTEM
10508
HEATING
TEMPERATURE
OVERHEAT
RESET
BOILER
OFF
Expansion
vessel
Air supply
tube
Lock-out
button
Burner
Pump
Pump
isolating
valves
Condensate
trap
Drain tap
Figure 7-4:
System model (also refer to Figure 7-3
3. Using a suitable screwdriver rotate
the exposed spindle about one turn.
4. Replace the plug and cap.
7.5 Pressure Relief Safety Valve
Now the pressure relief safety valve
operation must be checked and set. The
procedure is as follows:
1. Check the operation of the safety
valve (see Figure 7-3) by turning the
head anticlockwise until it clicks. The
click is the safety valve head lifting
off its seat allowing water to escape
from the system.
2. Check that the water is escaping
from the system.
3. Continue to fill the system until the
pressure gauge indicates between
0.5 and 1.0 bar.
4. Close the fill point valve and check
the system for water soundness,
rectifying where necessary.
5. Water may be released from the
system by manually operating the
safety valve until the system design
pressure is obtained. The system
design pressure (cold) should
be between 0.5 bar and 1.0 bar.
The pressure is equivalent to the
maximum static head in bar + 0.3 (1
bar = 10.2 metres of water), where
the static head is the vertical height
from the centre of the expansion
vessel to the highest point of the
system.
Now close the valves either side of the
filling loop and disconnect the loop.
