IM-P157-38
CMGT Issue 4
16
Steam/Water Mixing Stations (MkII valves - 2002 onwards) Safety and Operation
4.2.2 Installation
Remove the wall bracket from the mixing valve. Screw the wall bracket to the wall in the final position, using
a suitable fitting. Thread the valve back onto the wall bracket.
When replacing a steam/water mixing valve in a mixing valve station the spool pieces supplied must be
installed between the pressure gauge 'T' piece and the mixing valve union in the steam and cold water supply
lines. This will take account of the smaller overall dimension of the replacement valve.
The pipework should be assembled according to Figure 4 using a suitable thread sealing medium. The
temperature cut-out valve (
N
) is only provided on
½
" and
¾
" sizes.
NOTE: The minimum supply pressures for the steam and water must be such, that a pressure drop
of at least 1 bar (14.5 psi) is maintained across the valve. The maximum pressure for each supply
is 10 bar (145 psi). Steam and water pressures are required to be nominally equal. (Please see
Section 7, 'Fault finding' for details).
To connect the thermometer, screw the reducing bush (
M
) into the top of the 'T' piece (
K
); push the
thermometer (
E
) into the pocket (
L
) and lock in place with the grub screw; tighten the pocket into the
reducing bush.
To connect the hot water supply pipework to the hot water outlet of the steam/water mixing valve first screw
the thermometer 'T' piece and TCO1 to the hot water pipe. This arrangement should then be attached to the
steam/water mixing valve using the hot water outlet union fitted to the mixing valve. Care should be taken to
ensure that the dial face of the thermometer and the hexagon cap of the TCO1 are in line with the temperature
adjustment knob (see Figure 4).
IMPORTANT NOTE:
The installation should be completed so as to comply with any Local Water Board Regulations,
with regard to direct use of mains water supply. A break tank may be required to provide an air gap
for each valve.
If a booster pump is being used to supply an adequate constant cold water supply pressure, then
pressure switches must not be used, since this can affect the operation of the steam/water mixing
valve station. Installation of a balanced line arrangement should be considered; (a typical layout
is shown in Figure 12).
4.3 Installation for hosedown purposes
The steam/water mixing valve station should be carefully unpacked and the contents checked against the
packing list (see the Table on page 18 in conjunction with Figure 5).
