How to Replace a Mira Combiforce Cartridge (UK)
Fit a genuine 617 cartridge in a Mira Combiforce. UK isolation, service pattern and cold flush.
Mira
Identify
The Mira Combiforce uses the 617 cartridge. Confirm from the label under the temperature knob before ordering.
Isolate
Turn off hot and cold supplies — usually 15 mm service valves either side of the valve, or the local isolators under the floor. Open the valve to drop pressure.
Fit
Remove the temperature knob (grub screw at 4 o'clock on most Mira valves). Undo the retaining nut, withdraw the old cartridge. Grease O-rings with silicone grease, fit new cartridge, torque nut to 12 Nm.
Commission
Flush cold-only for 30 s to clear any grease. Set stop position — on TMV2 units, set to 41 °C at maximum.
Frequently asked questions
- OEM or compatible?
- Mira thermostatic cartridges must be OEM to preserve the TMV2 approval on hotels, care homes and schools.
- How often to replace?
- Hard water: every 2–3 years. Soft water: 5+ years.
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