20
14 DISASSEMBLY SEQUENCE OF MAINTENANCE
15 DEMOUNTING THE MIXER FOR DISINFECTION
9.1
THERMOSTATIC CARTRIDGE AGEING
Following many years of normal service you may notice the following:
1. The need to carry out more frequent adjustment of mixed temperature.
2. The thermostatic element may not pass the CWI test.
These issues could be due to the ageing of the thermostat which loses some expansion capability over
time.
These are the principle objectives of testing, as they serve to indicate to maintenance staff the declining
performance capability of the thermostatic cartridge.
For this reason the audit testing flow chart highlights that 2nd Instance CWI test failure or 2nd instance
mixed deviation even with stable ‘as commissioned’ supply conditions and correct inlet supply Δt’s, is
potentially the first indication of the need to replace the cartridge.
Disassembling sequence to access cartridges & demount the mixer:
1.
Isolate both HOT & COLD water supplies first. Use inline service valves if fitted.
2.
Fully open the flow or diverter handle, to confirm water is switched off. Unscrew
the shower hose from the underside of the mixer. This will permit some of the
trapped water to drain down & release water pressure from the outlet.
3.
To access cartridges, it will be necessary to remove handles first.
See section 16.
4.
Ensure parts are re-assembled in the correct ‘reverse’ sequence.
5.
Restore both water supplies. Refit the shower hose.
6.
Check all joints for leaks upon completion.
7.
Run water through the mixer for a few seconds to purge-out any trapped air.
In response to the new requirements of HTM 04-01 Addendum, the design of this
product permits easy demounting of the mixer from the inlets.
This design permits quick & easy removal of the mixer for cleaning, disinfection and
maintenance purposes.
General advice:
1.
Use correct size tools. Avoid damaging chromed surfaces, use a strap wrench if possible.
2.
When unscrewing cartridges or demounting the mixer, expect some trapped water to escape from
within the mixer body.
3.
Wash all parts (strainer meshes etc.…) in clean water before re-assembly.
4.
Observe torque settings, where specified.
