WATER REGULATIONS
Hot and cold water supply pressures must be
reasonably balanced and from a common
source - both from storage or both from a
supply pipe. (IRN 101). The mixers will function
within specification on unequal pressures up to
a ratio of 5 : 1, but it is not recommended that
the cold supply be connected to the rising main
and hot to the tank fed supply as the pressure
differential is likely to exceed the 5:1 ratio.
The minimum pressure for correct operation is
0.1 bar (1m head - see Figure 5). Pressure head
is measured as the vertical distance between the
bottom of the cold water storage tank which
feeds the hot water system and the highest
point on the shower spray plate.
When installing with a shower pump the use of
a secondary tapping from the cylinder is highly
recommended.
Figure 1 shows the various methods of connecting
the hot water pipe to the cylinder - the most
preferred on the left and the least preferred on
the right.
The fitting should be so installed as to be readily
accessible for examination, repair, replacement or
operation. (IRN 111).
The temperature of the hot water must not exceed
85ºC but the installer’s attention is drawn to code
of practice BS 6700 which recommends that
stored hot water should normally never exceed
65ºC. For correct operation of the valve, a
minimum of 52ºC is required.
GENERAL NOTES
Trevi thermostatic shower mixers are designed to be installed on normal UK low
pressure storage tank fed systems, unvented high pressure systems, modulating
instantaneous water heaters or modulating combination (combi) boilers. They are suitable
for all pumped applications.
Figure 1 Preferred locations of cylinder tapping
1
FOR HEALTHCARE ESTABLISHMENTS
In accordance to NHS model engineering specification DO8 the valve has approval for the following
applications: -
High pressure -HP-S
Low pressure
-LP-S
TMV3 approval number:
ETC/227/0903
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