Unvented Hot Water Cylinders
Unvented hot water cylinder installation & servicing in Chelmsford and Essex.
Plumbers ESX installs, replaces and services unvented hot water cylinders across Chelmsford and Essex. Connor is G3-qualified to work on these pressurised hot water systems. Tell us whether you need a service, a replacement or a cylinder for a new installation.
The Work
Overview
An unvented cylinder stores hot water in a sealed vessel supplied directly from the cold-water mains. It supplies taps and showers without a separate cold-water storage cistern feeding the cylinder. It is also described as a pressurised or mains-pressure hot water cylinder.
Talk to us
Service, replacement or new installation.
Tell us your postcode, whether you need a service, a replacement or a new installation, and the make and model of your cylinder if you know it. The pressure and flow you can achieve depend on your incoming water supply and pipework; a cylinder alone cannot correct a weak main, so we assess the supply before recommending anything.
What's Included
Our service expertise.
01
Installation
New builds, suitable conversions from vented systems, and cylinders specified as part of bathroom or heat pump projects. Pipework, controls, discharge route, sizing and commissioning all matter, so we choose the system after an assessment, not before.
02
Replacement
For a leaking or deteriorating cylinder, or one that no longer suits the household. Poor hot water does not automatically mean the vessel must be replaced; faults can sit in the controls, immersion or supply, and an assessment establishes the next step.
03
Servicing
Model-specific safety and operation checks on existing cylinders, even when the hot water seems normal. Tell us the make, model and last service date when you book. A cylinder service is separate from a boiler service.
Our Process
Precise from survey to handover.
01
Tell us what you need
Service, replacement or new installation, plus your postcode and the cylinder make and model if known. A photo of the cylinder and its label helps.
02
Assessment
We check the incoming mains pressure and flow, the space and access, the heat source and a safe route for the discharge pipework.
03
Clear recommendation
Repair, service or replace, with the reasoning explained in plain language and a written quote before any work starts.
04
The work
Carried out by a G3-qualified engineer, to the manufacturer's instructions and current Building Regulations.
05
Commissioning & records
Tested, commissioned and recorded. Applicable notification and commissioning arrangements are agreed with you before work begins.
Choosing a Cylinder
Before choosing a new cylinder.
- 01How many people live in the house, and how many baths or showers are likely to run at the same time.
- 02The mains pressure and, just as importantly, the available flow from your incoming water supply.
- 03The heat source: boiler, electric immersion or heat pump, and how quickly the cylinder reheats.
- 04The space available, access for installation, and whether the floor can support a full cylinder.
- 05A suitable discharge route with the required visible discharge point and safe termination.
Unvented versus vented is one distinction; direct versus indirect is another. A vented cylinder is typically fed by a cold-water cistern positioned above it, often in the loft, while an unvented cylinder is fed directly from the mains. A direct cylinder is usually heated by an immersion heater; an indirect cylinder is heated by a coil connected to a compatible boiler or heat pump, and may also have an immersion as a backup.
If you are planning a heat pump, the cylinder needs to be specified for it. Read more on our air source heat pump installation page, or see how cylinders fit into our new build plumbing and heating work.
Servicing
What does an unvented cylinder service involve?
Servicing is led by the manufacturer's instructions for your specific model, carried out by a qualified engineer. The exact checks depend on the cylinder, but a service typically covers:
- A visual inspection for signs of leaks, corrosion or deterioration.
- The expansion arrangement, whether that is an internal expansion provision or a separate expansion vessel.
- The pressure and temperature relief valves and the discharge pipework path.
- Operating controls and overheat protection.
- Inlet controls and the strainer, where fitted.
- A record of the service and any findings.
Annual servicing is commonly specified by manufacturers; follow your own manual and warranty terms. A cylinder service is not the same as a boiler service, and not every remedial repair or part is automatically included, so we confirm the scope when you book.
Not Sure What You Have?
Send us a photo and we will take it from there.
If you are not sure what cylinder you have, email a photo of the cylinder and its label (if it is easy to see) to plumbers.esx@hotmail.com, along with your postcode, whether you need a service, a replacement or a new installation, any symptoms you have noticed, and the date of the last service if you know it. There is no need to remove any covers.
One safety note: if water is discharging through the tundish (the visible air gap in the discharge pipe), the system needs professional attention. Do not block the discharge pipe or alter the safety valves. If the water is abnormally hot or you can see steam, stop using the system, switch off the heat source only if it is safe to do so, and seek qualified help urgently.
Qualifications
What G3 means for your home.
Unvented hot water cylinders work under pressure, so Building Regulations hot water safety requirements and manufacturer instructions apply to their installation and servicing. Connor is G3-qualified, the recognised qualification for working on these systems.
Before any installation begins, we agree the applicable notification and commissioning arrangements with you, so the paperwork is in order when the work is finished.
Common Questions
Things people ask us.
How often should my unvented cylinder be serviced?
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Most manufacturers specify annual servicing to keep the cylinder safe and to maintain warranty terms. Check your own manual and warranty documents, and follow what they say for your model.
Is a cylinder service included in a boiler service?
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No. A boiler service covers the boiler; an unvented cylinder is a separate appliance with its own safety checks. If you want both done in one visit, tell us when booking so the scope is clear.
Will an unvented cylinder improve my shower pressure?
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It may improve performance compared with a gravity-fed system, but this depends on the available mains pressure and flow, pipework and shower fittings. A cylinder alone cannot correct a weak main.
Can a vented cylinder be replaced with an unvented one?
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Often, yes, but it depends on a survey: the incoming mains pressure and flow, the space available and a safe route for the discharge pipework all need to be confirmed first.
Do I need a new cylinder with a heat pump?
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Not necessarily. The cylinder must be suitable for the proposed heat pump; we assess your existing cylinder before recommending replacement. Heat pumps heat water at lower temperatures than most boilers, so the cylinder needs a heat-transfer coil large enough to pass that heat into the stored water and reheat it in a reasonable time.
What information should I send when booking?
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Your postcode, whether you need a service, replacement or new installation, the make and model of the cylinder if you know it, the date of the last service if known, and any symptoms you have noticed. A photo of the cylinder and its label helps a lot.
★★★★★ 5.0 on Google
What customers say about our plumbing and heating work.
Every review is a verified 5★ Google review from a real Essex homeowner or developer we've worked with.
Verified Google Reviews
Connor did a brilliant job, came over very quick when our hot water wasn't working and got it fixed. Would definitely recommend.
flitty100
Hot Water Repair
Great service. Had a new water heater and new taps fitted by Connor. High standard, friendly and a fair price. Would definitely recommend.
Lynne Holloway
Water Heater & Taps · Upminster, Essex
I couldn't be happier with the service I received. Four new radiators installed at a great price, and the entire job completed in just one day. Everything was left clean and tidy and all the radiators were working perfectly before they left. Excellent value for money and clearly takes pride in their work.
Joe Smith
Heating & Radiators
We had Plumbers.ESX in for our new build house, amazing standard of work, installing the whole of the heating system and gas works including the underfloor, and all of the bathrooms. Really reliable guys.
Curt Stephens
New Build Heating & Bathrooms
Every review above is a verified 5★ Google review from a real Essex customer.
Read all Google reviewsWhere We Work
Unvented Hot Water Cylinders across Essex.
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