Do Hot Water Cylinders Need Servicing? Here’s What Every Homeowner Should Know

When people think of heating maintenance, the first thing that comes to mind is the annual boiler service. But if you have a hot water cylinder in your home, it’s just as important to give it some attention.

Why Cylinders Matter

Hot water cylinders are the heart of your home’s hot water system. They store and supply the water you use for showers, taps, and baths every day. While they don’t have as many moving parts as boilers, they do contain vital safety components that need to be checked regularly.

Unvented Cylinders – Annual Servicing Is Essential

Unvented cylinders (such as Megaflo or Heatrae Sadia systems) are pressurised units. By law, they must be serviced every 12 months by a G3-qualified engineer.A typical service will include checks on:

• Safety valves and discharge pipework

• Expansion vessel pressure

• Temperature and pressure relief controls

• Filters and strainers

These tests make sure the cylinder is running efficiently and, most importantly, safely.

Vented Cylinders – Don’t Ignore Them

Traditional vented cylinders (with a cold-water tank in the loft) don’t legally require annual servicing. However, they still benefit from periodic checks for:

• Insulation quality

• Signs of leaks or corrosion

• Scale build-up

• Cold-water storage tank condition

A neglected vented cylinder can become inefficient or even fail prematurely.

Why Service Both Together?

If you already have a yearly boiler service booked, it makes sense to have your cylinder serviced at the same time. Benefits include:

• Cost efficiency – one visit, one engineer

• Peace of mind – the entire heating and hot water system checked at once

• Longevity – regular maintenance extends the life of both your boiler and cylinder

  
  

Think of your heating system as a team: the boiler and the cylinder work hand in hand to keep your home comfortable. Looking after both ensures you get safe, reliable hot water and heating all year round.

If your boiler service is coming up, ask your engineer whether your cylinder should be checked at the same time. It’s a small step that can save you big headaches later.

For more information on boiler services and maintenance, check out our Boiler Maintenance page.