Jet Selection; Step 1: Vertical Framing; Step 2: Installation For Thin And Thick Wall Linings; Step 3: Pipe Connections - METHVEN KOHA SHOWER MIXER WITH FASTFLOW II Installation Manual

JET SELECTION:

Equal Pressure Systems
Fit mixer as supplied.
Unequal Pressure Systems
If the system is supplied by a pressure pump, ensure that
the pump can maintain 300kPa at the cold Inlet. If not,
install a low pressure cold feed and install the mixer as if for
a low pressure equal system.
Use the following table to determine the nozzle to be used.
Hot Pressure Primary Nozzle
17-25 kPa Black
25-50 kPa Green
50-90 kPa Yellow
90-130 kPa Red
IMPORTANT: Before you begin, turn off the water supply.
Step 1
• Refer to section above for correct nozzle selection.
• Install a horizontal support at the required height for correct positioning of the mixer.
Ensure front of horizontal support is in line with front of the framing.
Step 2
For thin wall linings (eg acrylic showers):
• Position mixer body on horizontal support with the front edge of the black spacer flush with front of the
horizontal support.
• If necessary, loosen the plastic cover and leave in place during the installation.
For thicker wall linings (eg tiles):
• Remove black spacers from under the mounting bracket.
• Position mixer body on horizontal support with the front edge of the mounting bracket flush with front of
the horizontal support.
• Secure mixer body to the horizontal support with four suitable screws, ensuring it is oriented square.
• Alternatively, the mixer can be mounted to support timber behind the mixer maintaining the same
placement as above.
Step 3
• Flush all pipe-work thoroughly prior to the next step.
• Connect hot and cold supplies and outlet to mixer body ensuring a good seal at each joint.
• Leak test installation prior to closing wall cavity.
• The seal integrity of pipe joins is the responsibility of the installing plumber.
Step 4
• Wall lining hole should be cut or finished as per the dimension shown in the diagram on the right.
• Allowable distance from front of horizontal support to finished wall surface:
– With spacer = 9 – 31mm
– Without spacer = 15 – 37mm
Step 5
• Remove plastic cover. Do not discard the screws.
• Apply silicone to the faceplate to create a seal with the finished wall surface. Ensure the silicone
does not block the notch in the faceplate.
• Slide faceplate onto mixer body, and position faceplate with notch towards the bottom.
• Fasten faceplate to the mixer body with screws previously removed.
• Fit dome cover onto the mixer body.
• Push handle on to cartridge lever and tighten grub screw firmly with hex key provided.
Fitment of the primary nozzle into the mixer body
• Remove the dome cover (if fitted) and unscrew the lock nut.
• Take hold of the cartridge and with a gentle circular motion pull the cartridge straight out of the mixer body.
Note: Do not turn the cartridge.
• Fit the recommended nozzle into the cartridge as shown as per the table.
• Refit the cartridge ensuring that the 2 outer seals are in place. Refit the lock nut applying a torque of 12 Nm
and refit the dome cover.
•
Vertical Framing
Horizontal support
Hot
100mm ±2
Front edge of spacer
Front edge of
mounting bracket
Outlet
Cold
9 – 31mm
with spacer
15 – 37mm
without spacer