Unvented cylinder G3 safety service — £90.

Why an annual G3 service matters

An unvented cylinder is essentially a sealed pressurised hot water tank. Like any pressure vessel, it has safety devices — a temperature-and-pressure relief valve, an expansion vessel, and a tundish — that need to be checked annually.

• It's a legal requirement for installation (Building Regs G3) and recommended annually
• Most manufacturer warranties require an annual service to remain valid
• A failed expansion vessel or stuck T&P valve is a serious safety risk

What we do during the service

• Check and re-pressurise the expansion vessel
• Test the T&P relief valve operation
• Check tundish and discharge pipe for blockages
• Test temperature operating ranges
• Inspect immersion heater and thermostats
• Issue a service record for your records

Combine with a boiler service for £180

If you're due both a boiler service and a cylinder service in the same year, we combine them for £180 + parts. Saves a separate callout.