Unvented and open-vented hot water cylinders

Want more hot water, or better pressure from the shower? An unvented cylinder stores hot water at mains pressure, so you can run a shower and a tap at the same time. We install, repair and service unvented and open-vented cylinders.

Unvented hot water cylinder and expansion vessel in a cupboard

When to call us

  • Weak showers fed from a tank in the loft
  • Running out of hot water with a busy household
  • A leaking or corroded copper cylinder
  • Water dripping from the cylinder’s discharge pipe
  • An immersion heater that has stopped working

What’s included

  • Unvented cylinder installation with all safety valves
  • Annual unvented cylinder servicing
  • Immersion heater and thermostat replacement
  • Expansion vessel and pressure relief valve repairs
  • Removing old tanks from the loft

Hot water repairs

Hot water repair is one of the jobs our reviewers mention by name. Cylinders have several safety devices that wear over time; we will find the faulty part and fix it the same day where we can.

Engineer connecting pipework to a new hot water cylinder
Copper pipework on a newly installed cylinder

Photographs from Green PHS jobs.

What customers say

“Technical knowledge of work required was exhibited, and competitive and comprehensive estimates were given. An energetic and efficient outfit that accommodated changes without the "sucking of teeth" that often accompanies such things.”

Barry Paul, Google review

4.8

from 201 Google reviews

Read more reviews

Radiators, underfloor heating, cylinders, power flushing and smart controls.

Hot water cylinders: common questions

Do unvented cylinders need servicing?

Yes. They should be checked once a year by a qualified engineer, and the manufacturer’s warranty usually requires it.

Ask about hot water cylinders

We reply the same working day. For an emergency, call 020 8050 5913 instead.

So we can check we cover your area.

Boiler make, what it is doing, any fault code, and when suits you.

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Call Lee. He picks up.

Tell him what is happening. If it is a quick fix, he will talk you through it for free. If not, we will get an engineer to you, usually the same day.

Call Lee Get a quote