Commissioning and in-service
tests
Commissioning
Purpose
Since the installed supply conditions are likely to
be different from those applied in the laboratory
tests it is appropriate, at commissioning, to carry
out some simple checks and tests on each mixing
valve to provide a performance reference point for
future in-service tests.
Procedure
1. Check that:
a) the designation of the thermostatic mixing
valve matches the intended application
b) the supply pressures are within the range of
operating pressures for the designation of
the valve
c) the supply temperatures are within the range
permitted for the valve and by guidance
information on the prevention of legionella
etc.
2. Adjust the temperature of the mixed water in
accordance with the manufacturer's instructions
and the requirement of the application and then
carry out the following sequence:
a) record the temperature of the hot and cold
water supplies
b) record the temperature of the mixed water
at the largest draw-off flow rate
c) record the temperature of the mixed water
at a smaller draw-off flow rate, which shall
be measured
d) isolate the cold water supply to the
mixing valve and monitor the mixed water
temperature
e) record the maximum temperature achieved
as a result of (d) and the final stabilised
temperature
NOTE: The final stabilised mixed water
temperature should not exceed the values in
Table A.
10
f)
record the equipment, thermometer etc. used
for the measurements
Table A: Guide to maximum stabilised
temperatures recorded during site
tests
Application
Shower
Washbasin
Bath (44°C fill)
Bath (46°C fill)
The mixed water temperature at terminal fitting
should never exceed 46ºC.
If there is a residual flow during the commission-
ing or the annual verification (cold water supply
isolation test), then this is acceptable providing the
temperature of the water seeping from the valve is
no more than 2°C above the designated maximum
mixed water outlet temperature setting of the valve.
Temperature readings should be taken at the normal
flow rate after allowing for the system to stabilise.
The sensing part of the thermometer probe must be
fully submerged in the water that is to be tested.
Any TMV that has been adjusted or serviced must
be re-commissioned and re-tested in accordance
with the manufacturers' instructions.
Mixed water
temperature
43°C
43°C
46°C
48°C