Immergas MAGIS M4-30 Use And Installation page 71

e units are tted with an 8L expansion vessel with a default pre-pressure of 1.0 bar.
vessel might need to be adjusted to guarantee proper operation of the unit.
1) Check that the total water volume of the system always available and not shut o , excluding the internal water volume of
the unit, is at least 40L. See Chap. 14 "Technical speci cations" to nd the total internal water volume of the unit.
NOTE
n the majority of applications, this minimum water volume will be satisfactory.
• However in critical processes or in environments with a high thermal load, additional water could be necessary.
• When the circulation in each space heating circuit is controlled by remote control valves, this minimum water volume
needs to be maintained even if all the valves are closed.
Using the table below, determine whether the pre-pressure of the expansion vessel needs to be adjusted.
3) Using the table and the instructions below, determine whether the total water volume of the system is less than the maxi-
mum admissible water volume.
height
di erence (*)
≤ 7 m No pre-pressure adjustment is necessary
Required actions:
• e pre-pressure must be increased, calculated
according to: "Calculation of expansion vessel
pre-pressure" (see below).
> 7 m
• Check whether the water volume is less than
the maximum admissible volume (use the chart
below).
(*): the height di erence calculated between the highest point of the water circuit and the expansion tank of the heat pump.
Unless the unit is located at the highest point of the system, in which case the installation height di erence is considered zero.
Calculation of the expansion vessel pre-pressure.
e pre-pressure to be set depends on the maximum di erence in the installation height (H) and is calculated as follows:
Pg(bar)=(H(m)/10+0.3))bar
Calculation of the maximum admissible water volume.
To determine the maximum admissible water volume in the entire circuit, proceed as follows:
• Determine the calculated pre-pressure (Pg) for the corresponding maximum water volume using the chart below.
• Check that the total water volume of the entire water circuit is less than this value. Otherwise the expansion vessel inside
the unit is too small for the installation.
Water volume ≤ 230L
e pre-pressure of the expansion
Water volume > 230L
Required actions:
• e pre-pressure must be increased, calculated
according to: "Calculation of expansion vessel
pre-pressure" (see below).
• Check whether the water volume is less than
the maximum admissible volume (use the graph
below).
Expansion vessel of the unit too small for the
system.