Stuart Turner Mainboost MJ3 VM - 8 COMMISSIONING; System check; Check vessel pre-charge pressure; Check mains static pressure

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8 COMMISSIONING
8.11 System check: Ensure that the electrical supply to the pump is switched off
before opening the mains water supply stopcock and checking for leaks.
8.12 Check vessel pre-charge pressure:
It is important to have the correct pre-charge pressure in the vessel for your
site conditions to optimise performance. The vessel is supplied with a
pre-charge pressure of approximately 1.4 bar, and should never have a preset
pressure of less than 0.5 bar.
Checking and adjustment to the vessel pre-charge air pressure can only be
carried out when the vessel is empty (contains no water).
8.13 Check mains static pressure:
z Now close outlets and check pressure gauge after ‘Y’ strainer – for static
mains pressure and note it. This should be done at peak times of use.
z Turn stopcock off and leave outlet taps open.
8.14 Check the chart below for the correct vessel pressure against the static mains
pressure recorded.
Using a pressure gauge check the vessel and adjust to suit through the
schrader valve.
Warning: NOTE PRV setting must not exceed 5.0 bar.
MJ3 pump max.
set pressure
Static mains
pressure
Set vessel
pre-charge
pressure to
Differential
Set PRV
maximum
setting to
bar bar bar bar
3 bar 1.0 1.2 1.8 1.0
3 bar 1.5 1.2 1.8 1.5
3 bar 2.0 1.2 1.8 2.0
3.5 bar 2.5 1.7 1.8 2.5
3.5 bar 3.0 1.7 1.8 2.5
Fig. 28