Water Volume And Expansion Vessel Pressure; The Method Of Calculating The Charging Pressure Of Expansion Vessel - Sinclair STHERM SMH IRB Series Installation Manual

Note
See the curve above for the maximum external static pressure. The water pump is of variable frequency. And
during operation, the water pump will adjust its output based on the actual load.

7.2 Water volume and expansion vessel pressure

Notes
(a) The expansion vessel is 2 liter and 1.5bar pre-pressurized for 4/6/8kW unit; 3 liter and 1.5bar per-
pressurized for 10/12/14/16kW unit ;
(b) Total water volume of 44 liter is default for 4/6/8kW unit and 66 liter for 10/12/14/16kW unit; if total water is
changed because of installation condition, the pre-pressure should be adjusted to secure proper operation. If
the unit is located at the highest position, adjustment is not required;
(c) Minimum total water volume is 20 liter;
(d) To adjust pre-pressure, use nitrogen gas by certificated installer.

7.3 The method of calculating the charging pressure of expansion vessel

The method of calculating the charging pressure of expansion vessel needed to be adjusted is as follows.
During installation, if the volume of water system has changed, please check if the pre-set pressure of the
expansion vessel needs to be adjusted according to the following formula:
water system)
Ensure that the volume of water system is lower than the maximum volume required in the above figure. If it
exceeds the range, the expansion vessel does not meet the installing requirement.
Bar (H ---the difference between installing location of indoor unit and the highest spot of
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