UK trade guideToilet & Cistern 6 min readUpdated 9 July 2026

How to Replace a Macerator Pump (UK)

Swap a Saniflo, Sanicompact or Sanislim macerator. When to repair vs replace, motor and cutter parts.

SanifloGrundfosStuart Turner

Repair or replace?

<5 years — repair. Common failing parts: micro switch, membrane, motor capacitor. >5 years or motor humming without spinning — replace whole unit.

Sizing

  • Sanicompact 43 — WC only, 5 m lift.
  • Saniplus — WC + basin + shower, 5 m lift, 100 m run.
  • Sanibest Pro — heavy-duty, grinds sanitary waste, 7 m lift.

Fit

Isolate power. Isolate cold. Drain the unit (small purge valve). Disconnect all inlets and 40 mm outlet. Fit new unit with a rubber sound mat under.

Frequently asked questions

Can I DIY a Saniflo?
Yes for the unit itself. But Building Regs require the discharge to a mains soil stack via a non-return valve — check the whole path.
Shop the spares

Browse toilet & cistern6,230 live parts.

View Toilet & Cistern