Hot Water Cylinders

Expert Cylinder Services

No hot water? Cylinder not working properly? Need your annual service? Whatever the issue, LDF Plumbing & Heating has you covered. We are G3 registered specialists with over 15 years of experience working with both unvented and vented hot water systems.

Our cylinder services include:

Service — annual maintenance to keep your cylinder running safely and efficiently
Installation — new cylinder installations for new builds and renovations
Supply — we source and supply cylinders from leading manufacturers
Replace — like-for-like or upgraded replacements
System re-design — reconfigure your hot water system for better performance
System upgrade — move from vented to unvented for mains-pressure hot water

G3 Registered — UDHW110269

By law, only G3 qualified engineers can install, commission and service unvented hot water cylinders. Our G3 registration number is UDHW110269. This means you can be confident that all work on your unvented system is carried out safely, to current Building Regulations, and will be signed off correctly.

Unvented Cylinders

Unvented hot water cylinders are connected directly to the mains water supply, delivering hot water at mains pressure to every tap and shower in your home. No cold water tank in the loft, no gravity feed — just powerful, consistent hot water throughout.

Unvented Cylinder Service Checklist

Check and test the temperature and pressure relief valve (T&P valve)
Check and test the expansion vessel or expansion relief valve
Check the tundish and discharge pipework for signs of dripping or discharge
Check the immersion heater thermostat and operation
Inspect the cylinder for physical damage, corrosion or leaks
Check the cold water mains pressure and flow rate
Test the pressure reducing valve (where fitted)
Check all pipework connections for leaks or deterioration
Record all readings and issue a service certificate

Why Choose Unvented?

Mains Pressure

Powerful Hot Water

Hot water delivered at full mains pressure to every outlet in your home

No Loft Tank

Space Saving

No cold water storage tank required in the loft, freeing up valuable space

Multi-Outlet

Consistent Flow

Run multiple showers and taps at the same time without losing pressure

Vented Cylinders

Vented (or open-vented) hot water cylinders are fed by a cold water storage tank, usually in the loft. They rely on gravity to deliver hot water, which means lower pressure than unvented systems but a reliable and well-proven design that suits many homes.

Vented Cylinder Service Checklist

Inspect the cold water storage cistern for debris, corrosion or contamination
Check the ball valve and float for correct operation and shut-off
Inspect the open vent pipe for correct routing and termination
Check the immersion heater thermostat and operation
Inspect the cylinder for physical damage, corrosion or leaks
Check all pipework connections, gate valves and isolation points
Test the hot water temperature at the nearest draw-off point
Advise on energy efficiency and potential system upgrades

Annual Servicing Is Essential

Unvented hot water cylinders must be serviced annually by a G3 qualified engineer. This is a legal requirement and is typically a condition of your manufacturer's warranty. Regular servicing ensures your safety valves are functioning correctly, prevents costly breakdowns, and extends the life of your cylinder. Don't leave it until something goes wrong — book your annual service today.