Standard or reversed?

Standard Gainsborough cartridges close clockwise. Reverse handles will require the -R variant.

Silicone grease only — petroleum jelly attacks the EPDM seals.

OEM or aftermarket for Gainsborough?

For TMV2/TMV3 compliance always fit genuine Gainsborough cartridges. Aftermarket voids the GSi 10.5 electric approval.

Fit a new flow-control cartridge on the Gainsborough GSi 10.5 electric to fix stiff or leaking on/off — usually a 1/4-turn ceramic disc.

Close the built-in isolators on the Gainsborough GSi 10.5 electric valve body — accessed through the escutcheon plate.

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

Balance hot and cold to within 0.5 bar. Run the Gainsborough GSi 10.5 electric 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.

Standard or reversed?: Standard Gainsborough 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 Gainsborough?: For TMV2/TMV3 compliance always fit genuine Gainsborough cartridges. Aftermarket voids the GSi 10.5 electric approval.

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