How to Replace the Flow Cartridge on a Grohe Grohtherm 800 Bar (UK)
UK guide to swapping the flow cartridge in a Grohe Grohtherm 800 Bar shower valve. TMV2 compliance, part numbers, tools.
Grohe
The part
Fit a new flow-control cartridge on the Grohe Grohtherm 800 Bar to fix stiff or leaking on/off — usually a 1/4-turn ceramic disc.
Isolate
Close the built-in isolators on the Grohe Grohtherm 800 Bar valve body — accessed through the escutcheon plate.
Swap the flow cartridge
Some Grohe 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 Grohe Grohtherm 800 Bar 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 Grohe 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 Grohe?
- For TMV2/TMV3 compliance always fit genuine Grohe cartridges. Aftermarket voids the Grohtherm 800 Bar approval.
Shop the spares
Browse shower spares — 5,410 live parts.
View Shower Spares