CENWAT Water Heater Regulations 2

Question 1

What document must be completed when commissioning an unvented hot water cylinder?

Accepted Answer

Building Regulations Part G compliance notification and Benchmark commissioning checklist

Answer

Installation of an unvented hot water system is notifiable under Building Regulations Part G; the installer must notify the local authority (or use a Competent Person Scheme) and complete the Benchmark checklist.

Question 2

What temperature should an unvented cylinder thermostat be set to?

Accepted Answer

60–65°C

Answer

The cylinder thermostat on an unvented unit is typically set to 60–65°C to ensure Legionella prevention while remaining safely below the thermal cut-out and T&P relief valve activation temperatures.

Question 3

What is the purpose of the temperature and pressure relief (T&P) valve on a water heater?

Accepted Answer

To discharge hot water safely if the cylinder temperature or pressure exceeds safe limits

Answer

The T&P relief valve is a critical safety device that opens automatically if the cylinder temperature or pressure rises to dangerous levels, discharging water to prevent explosion.

Question 4

Where must the discharge pipe from a T&P relief valve terminate?

Accepted Answer

To a safe, visible point outside or to a tundish then to a drain, so discharge can be observed safely

Answer

The discharge pipe must terminate in a safe, visible location (typically outdoors) or via a tundish to a drain, so that any discharge is immediately apparent and does not cause harm or flooding.

Question 5

What is a tundish and why is it used with a T&P relief valve discharge pipe?

Accepted Answer

An open funnel fitting that provides an air gap, acting as a backflow break and allowing discharge to be observed

Answer

A tundish is an open funnel with an air gap that connects the T&P valve discharge pipe to the drain pipework. It prevents backflow contamination and makes discharge visible.

ACS CENWAT Practice Test

ACS CENWAT Practice Test

CENWAT Water Heater Regulations 2