User`s guide

Page 11
Figure 8: Isolation valve and filter supplied in LA MI
packages to be fitted to the heat pump return.
Figure 9: Isolation valve supplied in package to be fitted to
the heat pump flow.
Filling the system
The system should be filled with potable water. The
system water should be treated with standard central
heating inhibitors.
The cold fill gauge pressure on the heat pump should be
between 0.8 and 1.5 bar (0.08-0.15MPa). This will rise
during normal operation.
De-aeration
Air trapped in the system causes air locks which in turn
cause poor water flow around the system. Every high
point in the system should have a means of bleeding out
air which is supplied by the installer.
The pressure relief valve shown in Figure 11 can be used
to purge the air from the heat pump during filling.
Figure 10: Location of pressure relief valve
Figure 11: Pressure relief valve
Expansion vessel sizing
The heat pump comes with an expansion vessel already
installed as shown in the „Performance data table‟.
For most installations the 10L expansion vessel should
be able suitable with a volume up to 150L and a static
height of 7m. The 6L expansion vessel should be suitable
for a system volume up to 90L and a static height of 7m.
2 port valves
The heat pump packages include 2 x F228 Horstmann
two port valves as shown in Figure 12 to switch between
space heating and domestic hot water mode. Fit the
valves ensuring that the actuator head is not below the
horizontal level of the pipe work and that the flow is in the
direction of the arrow. Remember to make allowances for
maintenance and replacement.
Figure 12: Dimensions of F228 valve
The F228 valves have been specifically
selected for their fast operating times. When
switching from heating to DHW the heat
pump flow must not be restricted. If a
different valve is used, the valve must be
fully open within 6 seconds of being
switched.
Depending upon the specific system the
installer must determine if a second
expansion vessel is required.