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SPACE HEATING AND DHW
(9) Check Water Volume:
The unit has a built-in 8L expansion vessel, and default
initial pressure is 1 bar. To ensure the unit works
normally, the initial pressure of expansion vessel should
be adjusted according to the circulated water volume.
● Use water volume checklist below to decide whether
initial pressure of expansion vessel needs to be
adjusted.
● Use water volume checklist to confirm the total volume
of water in installation system is below the allowed
maximum water volume.
● Installation height difference: height difference between
highest point of water circulation and the unit. If the unit
is mounted at the highest point, above all water pipes,
the installation height is deemed to be 0 m.
● Calculate initial pressure of expansion vessel. Decide
initial pressure (Pg) according to the maximum
installation height difference (H), see below:
Pg=H/10+0.3
Unit: H (m), Pg (bar)
Water Volume Checklist
Installation height
difference (a)
≤7m
Safety Valve
(3 bar)
>7m
Maximum Water Volume Curve Graph
≤220L
No need to adjust initial pressure of expansion
vessel
Things need to do :
Must increase initial pressure. Calculate it based
on the section "Check water volume". Ensure
water volume is lower than allowed maximum
water volume (using the figures below).
2.8
2.3
1.8
1.3
0.8
0.3
0
50
100
150
Maximum Water Volume(L)
● The process of calculating allowed maximum water
volume in whole circulation is:
-
Calculate maximum water volume corresponding to initial
pressure Pg by using maximum water volume curve as
shown below.
-
Confirm the total maximum water volume in water
circulation is smaller than above value. Otherwise, the
expansion vessel in the unit is smaller for system.
●
0.3 bar is the minimum initial pressure and 1.5 bar is the
maximum initial pressure of expansion vessel set outside the
factory.
●
When initial pressure in expansion vessel is set as 0.3 bar
at minimum, the water quantity required by system is higher
than the limit value, it may be considered replacing expansion
vessel with bigger volume.
Water Volume
Things need to do :
Must reduce initial pressure.
Calculate it based on the section "Check water
volume". Ensure water volume is lower than
allowed maximum water volume (using the
figures below).
The expansion vessel is too small to install. (It
needs proper expansion vessel or use safety
valve with high activated pressure that is
supplied from local place)
200
250
300
350
18
>220L
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