172-65627M-09 (SQ10) 18 Oct 2021
56
A-(2):
For recirculating system hot water piping
In recirculating systems, the cold water supplied to the unit is heated, then
some is supplied to the point of use, and some is returned to the unit via
the recirculation piping.
a)
Install air vent(s), safety valves for pressure relief and expansion tanks
(if required) as appropriate on the hot water piping
b)
Install the mixing section (for hot water returned from the recirculation
piping and cold supply water) at least 1 m away from the cold water inlet
of the unit. This is to prevent erroneous operation of the flow switch.
B. Steam inlet piping
(1) Steam pipes should always be taken from the top of the steam main.
(2) Install a blow valve before the unit in order to be able to flush the
piping before the commissioning or after
the unit has been shut down for a long
period of time.
(3) Install a Y-type strainer on the steam
inlet piping to allow entrained foreign
matter to be removed during operation.
(4) Install a steam trap in order to prevent
condensate accumulating in steam
piping even if the unit is not in service or
stopped.
(5) If the steam supply pressure of the unit is 0.4 MPaG or more, the
pressure should be reduced with a pressure reducing valve, etc. The
pressure reducing valve should be installed as far as possible from the
unit (5 m or more is recommended) to obtain a stable steam supply
pressure. (Refer to the instruction manual for the pressure reducing
valve to be used.)
If a safety valve (relief valve) is installed between the pressure
reducing valve and the unit, the safety valve (relief valve) may operate
due to shut-off pressure rise when there is low demand on the unit, etc.
Install a shut-off valve before the pressure reducing valve, keep the
valve closed when not using the unit, and take measures so that the
safety valve (relief valve) does not operate due to shut-off pressure rise.
NOTE: If a pressure of 0.43 MPaG or more is applied to the unit, it falls
outside of pressure vessel regulation range, rendering the unit
unusable in legal terms. When the primary pressure of the pressure
reducing valve exceeds 0.43 MPaG, make sure to install a safety
valve (relief valve) between the pressure reducing valve and the unit.
SQ
Trap
(1)
(3)
(4)
(2)
