UK trade guideShower Spares 4 min readUpdated 11 July 2026

How to Replace the Flow Cartridge on a Aqualisa Aquavalve 509 (UK)

UK guide to swapping the flow cartridge in a Aqualisa Aquavalve 509 shower valve. TMV2 compliance, part numbers, tools.

Aqualisa

The part

Fit a new flow-control cartridge on the Aqualisa Aquavalve 509 to fix stiff or leaking on/off — usually a 1/4-turn ceramic disc.

Isolate

Close the built-in isolators on the Aqualisa Aquavalve 509 valve body — accessed through the escutcheon plate.

Swap the flow cartridge

Some Aqualisa valves use handed cartridges (L/R). Match the flat on the spindle to the handle orientation before refitting.

Commission

Balance hot and cold to within 0.5 bar. Run the Aqualisa Aquavalve 509 at max flow for 3 minutes.

Verify max outlet temperature stays below 46 °C per BS EN 1111 by shutting off cold and reading the outlet.

Frequently asked questions

Standard or reversed?
Standard Aqualisa cartridges close clockwise. Reverse handles will require the -R variant.
Any grease?
Silicone grease only — petroleum jelly attacks the EPDM seals.
OEM or aftermarket for Aqualisa?
For TMV2/TMV3 compliance always fit genuine Aqualisa cartridges. Aftermarket voids the Aquavalve 509 approval.
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