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Unvented hot water cylinder installation across Bristol. Strong, mains-pressure hot water to every tap, fitted by a fully qualified Gas Safe registered engineer.
Almost all of Julian's work comes from repeat customers and recommendations. Over forty years, that is the only measure that means anything.
An unvented cylinder is fed directly from the mains rather than from a tank in the loft. That means hot water arrives at full mains pressure, so showers are strong, baths fill quickly, and running two taps at once does not turn one of them into a trickle.
Julian holds the unvented hot water qualification, which is a legal requirement for this work. Unvented cylinders store water under pressure, so they are covered by Building Regulations and must be installed and serviced by someone qualified to do it. He is also Gas Safe registered, reg. 198984.
These systems suit larger homes and any house with more than one bathroom. If a combi boiler cannot keep up with your household, an unvented cylinder paired with a system boiler is usually the answer.
There are no loft tanks to freeze, overflow or gather debris, which is one less thing to worry about in an older Bristol property.
The top floor gets the same performance as the ground floor. No pump needed.
Unvented work is covered by Building Regulations and restricted to qualified engineers.
Nothing to freeze, overflow or gather debris. One less worry in an older property.
Part of central heating in Bristol.
A traditional vented cylinder is filled by gravity from a tank in the loft. The pressure you get at the tap depends on how far the water falls, which is why upstairs showers in older houses are often weak.
An unvented cylinder is sealed and connected straight to the incoming mains. The pressure at your shower is the pressure of the street main, so the top floor gets the same performance as the ground floor.
Because the water is stored under pressure and heats up, it expands. That is managed by an expansion vessel and a set of safety valves, and those components are the reason the work is regulated. Fitted properly, the system is completely safe and has been standard across Europe for decades.
The cylinder is heated by your boiler through a coil, so it pairs with a system boiler rather than a combi. Most also have an immersion heater as a backup if the boiler is ever out of action.
Your incoming mains needs to be up to the job. A cylinder cannot create pressure that is not there, so Julian measures the flow rate and static pressure before recommending one. If the supply is poor, he will tell you rather than fit something that will disappoint.
Absorbs the increase in volume as stored water heats, using a cushion of air behind a rubber diaphragm. That charge leaks away over the years, which is why the annual service exists and why a trickle from the outside discharge pipe is the usual first symptom.
Limits the incoming mains supply to the pressure the cylinder is rated for, so the system never sees more than it was designed to hold.
An expansion relief valve releases if pressure rises too far, and a temperature and pressure relief valve releases if the water overheats. Both discharge through a dedicated pipe terminating safely outside.
Unvented installations are notifiable under Building Regulations. The paperwork matters when you sell, because a solicitor will ask for it and its absence holds up a sale. It is also why the installer qualification is a legal requirement.
Getting the size right matters. Too small and you run out of hot water mid-shower. Too large and you pay to heat water nobody uses. As a rough guide, a three-bedroom home with one bathroom is usually served well by around 180 litres, and a larger house with two bathrooms often needs 250 litres or more.
Julian works the size out from the number of bathrooms, the household and how you actually use hot water, rather than from a chart.
Installation takes a day or two depending on whether you are replacing an existing cylinder or converting from a vented system. Converting means removing the loft tanks, upgrading the cold supply, and fitting the discharge pipework required by Building Regulations, which has to terminate safely outside.
Unvented cylinders need servicing once a year. The expansion vessel loses its charge over time, and the safety valves have to be checked. It is a legal requirement on rented property and a condition of most manufacturer warranties. Julian can carry that out alongside your annual boiler service.
The work is notified and certified as required, so your paperwork is in order if you come to sell the house.
The expansion vessel is the component that fails most often. It absorbs the extra volume as stored water heats and expands, and it does that using a cushion of air behind a rubber diaphragm. That charge leaks away slowly over the years, and once it has gone the safety valve starts discharging every time the cylinder heats.
The usual first sign is water trickling from the discharge pipe outside, often mistaken for a leak. Left alone it wastes a surprising amount of hot water and eventually damages the valve seat, which turns a straightforward recharge into a parts job.
Recharging the vessel and testing the safety valves is exactly what the annual service covers, which is why it is a legal requirement on rented property and a condition of virtually every manufacturer warranty.
Limescale is the other factor in the harder water around Bristol. It builds on the heating coil inside the cylinder and slows the reheat, so the family runs out of hot water sooner than it used to. Catching that early is far cheaper than replacing a scaled-up cylinder.
Julian can carry out the unvented service alongside your annual boiler service on the same visit, which keeps both warranties intact and saves a second appointment.
Cylinders have a working life of fifteen to twenty years or so, and replacing one before it fails is considerably less disruptive than dealing with a failure that has soaked a cupboard floor.
One point worth being clear about: the annual service on an unvented cylinder is not the same visit as a boiler service, even though the two are usually booked together. The cylinder has its own safety devices, its own expansion vessel and its own discharge arrangement, and all of them have to be tested by someone holding the unvented qualification. Skipping it is both a safety issue and, on most cylinders, a breach of the manufacturer guarantee.
The installer does. Unvented hot water work is covered by Building Regulations and must be carried out by someone holding the unvented qualification. Julian holds it.
Almost always, yes, provided your incoming mains supply is decent. There is no need for a separate shower pump because the water is already at mains pressure.
Once a year. The expansion vessel and safety valves have to be checked, and skipping it can invalidate the warranty.
No. An unvented cylinder is heated by a system or regular boiler through a coil. A combi heats water instantly and has no cylinder at all.
Usually an airing cupboard or a utility room. It needs to be somewhere the safety discharge pipe can run safely to outside, which Julian will check at the survey.
If you are weighing an unvented cylinder against a combi, the deciding questions are how many bathrooms are in simultaneous use and what your incoming mains supply actually delivers. Both are answered at the free survey rather than guessed at over the phone, and Julian will recommend the cheaper option where it genuinely suits the house.
See also boiler installation, central heating installation, combi boiler installation and boiler servicing. We cover Downend, Emersons Green and other areas.
Call Julian on 07831 718509 for a free survey. He will check your incoming mains supply, confirm where a cylinder could be sited and whether the safety discharge can be run correctly, then quote a fixed price with no obligation.
Changing cylinder type is usually done alongside central heating system replacement, because the floorboards are already up.
Free survey and a fixed quote, with honest advice on whether a cylinder is right for your home.