IM-P157-38
CMGT Issue 4
24
Steam/Water Mixing Stations (MkII valves - 2002 onwards) Safety and Operation
4.4 Start-up procedures
Cold water and steam supply pressures should have been determined prior to selecting the valve size.
If the valve is running to an open outlet; i.e. no restriction on the downstream side of the valve, the steam to
water pressure ratio, must not exceed, 3:1. It is advisable for the cold water pressure not to exceed the steam
pressure as this may inhibit the ability of the valve to produce hot water.
If there is a restriction on the outlet; e.g. hosedown gun, pipework or hose, control or isolation valve, etc. the
steam pressure and water pressure must be nominally equal.
4.4.1 Start-up
Follow the 'Safety test procedure' on page 4. If the valve passes this test, open the cold water inlet isolation
valve.
Do not point the gun at your body or anyone else, and hold with protective gloves.
Before
pulling the trigger hold the gun firmly in both hands and adopt a body position that will prevent loss of balance
due to recoil from the hosedown gun.
After use shut off the supply isolation valves. Discharge the contents and vent pressure from within the hose
and steam/water mixing valve station by pulling the trigger until water flow stops.
4.4.2 Setting temperature
Once correctly installed the temperature is adjusted as follows (refer to Figure 14):
a.
Remove the temperature adjustment knob retaining screw (
10
) and turn the temperature adjustment
knob (
12
) fully clockwise.
b.
Remove the adjustment knob and replace making sure that the retaining screw location is just
anticlockwise of one of the two location stops.
c.
Replace the retaining screw (
10
) and check that the temperature adjustment knob has at least 180
°
of
movement. If not, repeat Steps (
a
) and (
b
) positioning the retaining screw just anticlockwise of the other
location stop.
d.
Remove the bypass screw (
9
).
e.
Open the bypass valve fully anticlockwise.
f.
Turn the adjustment knob fully anticlockwise (coldest setting).
g.
Turn on the water and steam, then hold the gun open as per Section 4.4.1. Check the hot water
temperature. Turn the bypass valve (
8
) clockwise until either the temperature is just below that required
or the flow has been reduced significantly.
Note:
It is normal for the flowrate to decrease through the use of the bypass valve. If the flow is less
than that required please refer to 'Fault finding', Section 7.
h.
Turn the adjustment knob clockwise to increase the hot water temperature.
i.
If the desired temperature is not achieved, turn the adjustment knob fully anticlockwise and repeat
Steps (
g
) and (
h
).
Note:
The maximum hot water temperature is 90
°C (194
°F).
j.
Close the gun.
k.
Replace the bypass screw (
9
).
