How To Install A Bristan Frenzy — Trade Guide
The Bristan Frenzy is one of the most-fitted bar mixer showers in the UK. Whether you're installing one for the first time or swapping like-for-like, this trade guide covers the exact sequence — including the isolation and pressure-test steps DIY guides skip.
Step-by-step method
1. Isolate water and power
Turn off the mains stopcock and the electrical supply at the consumer unit — the Bristan Frenzy runs on a 40A or 45A dedicated circuit. Prove dead with a voltage tester.
2. Remove the existing unit
Undo the front cover. Photograph the wiring in the terminal block. Disconnect the 15mm cold feed at the top. Unscrew the back plate.
3. Fit the new back plate
Mark and drill for the Bristan Frenzy back plate — use Rawlplugs into brick, or fixings into stud where possible. Feed the cold supply and cable through the correct entry points.
4. Wire and plumb
Connect the cold to the 15mm inlet using a service valve for future maintenance. Wire the Bristan Frenzy exactly as the diagram — L, N and Earth. Torque terminals to 1.5Nm.
5. Commission
Restore water, purge air, then restore power. Run for 90 seconds on low setting to prove flow and heat, then full temperature test. Fill in the warranty card.
Frequently asked questions
Does a Bristan Frenzy need Part P notification?+
Electric shower circuits in bathrooms are notifiable under Part P. An electrician must certify or replace like-for-like on an existing circuit.
What kW rating is best?+
9kW gives 5 L/min at 35°C rise (winter), 10.8kW gives 6 L/min. 8.5kW is fine for southern England, 10.8kW recommended for Scotland / Northern homes.
How long does a Bristan Frenzy last?+
7–10 years typical. Element failure is the usual end-of-life fault. Descale monthly to double lifespan.