Unvented Hot Water Cylinders in Dunfermline & Fife
Installation, annual servicing and repairs on unvented cylinders across Dunfermline, Kirkcaldy, Dalgety Bay and Fife. Mains pressure hot water with no tank in the loft, fitted by G3 qualified engineers.
What we do with unvented cylinders
Installed, serviced and repaired by engineers qualified to work on them.
Cylinder installation
Replacing a vented cylinder or a tired unvented one, or converting from a tank in the loft. Sized to your bathrooms and your mains flow rather than guessed.
Get a quote →Annual servicing and testing
Unvented cylinders must be checked every year by a qualified engineer. Expansion vessel, pressure settings, the temperature and pressure relief valve and the discharge pipework all tested and recorded.
Book a service →Repairs
Leaking, dripping outside, no hot water, pressure dropping or water hammering. A repair visit is a fixed £120 inc VAT.
Book a repair →Advice on what suits
Not sure whether an unvented cylinder, a combi or a heat pump cylinder is right for your house? We check the mains flow and tell you straight.
Ask us →
Why the annual service is not optional
An unvented cylinder is a sealed vessel of water heated well above boiling point at atmospheric pressure. The safety devices are what stop that being a problem, and they are the parts that wear.
Building regulations require the work to be done by a qualified engineer, manufacturers require an annual service for the guarantee, and a landlord who skips it has a problem if anything happens. The service checks the expansion vessel charge, the pressure reducing valve, the temperature and pressure relief valve, the expansion relief valve, the thermostat and cut out, and that the discharge pipework runs where it should.
The most common thing we find is a flat expansion vessel, which shows up as water dripping from the outside discharge pipe and pressure that climbs when the cylinder heats. Left alone it wears the relief valve out, and then you have a leak rather than a drip.
Cylinder faults we repair
A repair visit is a fixed £120 inc VAT. Parts are quoted before they are fitted.
Water dripping outside
A pipe outside dripping after the hot water heats usually means a flat expansion vessel or a failed relief valve. The system is protecting itself, but it will not fix itself.
Book a repair →No hot water
Immersion, thermostat, cut out or a boiler side fault. We check which before anything gets replaced.
Book a repair →Pressure dropping or surging
The pressure reducing valve or the expansion vessel. Both are serviceable parts rather than a new cylinder.
Book a repair →Leaking cylinder
A leak from a fitting or valve is a repair. A leak from the vessel itself is a replacement, and we will tell you which it is.
Book a repair →Banging or water hammer
Usually a valve or the vessel charge, and it is worth fixing before it works a joint loose.
Book a repair →Hot water running short
Either the cylinder is undersized for the house or the coil or immersion is not heating it properly.
Book a repair →Most cylinder faults are a valve or an expansion vessel rather than a new cylinder. We tell you which it is, and if replacement genuinely is the better answer we price that too.
Cylinder leaking or dripping?
Send us a photo of the cylinder and the pipework on WhatsApp with your postcode, or book a repair visit online. We will tell you what it is likely to be and when we can be there.
Turn off the mains stop tap and switch the immersion and boiler off, then call us. A drip from the outside discharge pipe is the system working as designed, so it is not an emergency, but it does need looking at.
Qualified to work on them
Unvented hot water is notifiable work. Only an engineer holding the unvented hot water qualification, often called G3, can legally install or service one, and Building Standards expect the installation to be notified.
We hold the unvented qualification alongside Gas Safe registration, the water regulations certificate and our heat pump and F-Gas tickets. That means one visit can cover the cylinder, the boiler or heat pump feeding it and the pipework around it, rather than three trades blaming each other.
Cylinders for heat pumps
A heat pump needs a cylinder with a much larger coil than a boiler does, because it heats water more slowly at a lower temperature. Fitting a standard cylinder to a heat pump is one of the more common reasons a system never quite delivers.
We service and repair heat pump cylinders as part of our heat pump servicing, and if you are thinking about a heat pump later, we will tell you whether the cylinder you have now would suit it.
400+ five star reviews from homes across Dunfermline and Fife
Rated Excellent on Google, Trustpilot, Fife Trusted Trader and Facebook.
Every review is from a real Fife customer. Here is why.
Unvented cylinder questions
What is an unvented hot water cylinder?
A cylinder that stores hot water at mains pressure, fed straight from the incoming main. There is no cold water tank in the loft, and you get mains pressure hot water at every tap.
Do I need a cold water tank with one?
No. That is the point of them. The cylinder is fed directly by the mains, so the loft tanks can usually come out.
How often does an unvented cylinder need servicing?
Every year, by a qualified engineer. It is a manufacturer requirement for the guarantee and it is what keeps the safety devices working. The expansion vessel, the relief valves and the pressure settings are all checked and recorded.
What does it cost to repair one?
A repair visit is £120 inc VAT, which covers diagnosis and the repair where parts allow. Parts are quoted before they are fitted. Most cylinder faults are a valve or an expansion vessel rather than a new cylinder.
Why is water dripping from a pipe outside my house?
Usually the discharge from an unvented cylinder, and usually a flat expansion vessel or a failed relief valve. The system is protecting itself. It is not an emergency, but it needs fixing before the valve wears out.
Is an unvented cylinder suitable for every home?
No. It needs good mains flow and pressure coming into the house. We measure both before quoting, and if your mains cannot support one we will say so rather than fit it anyway.
Can I replace an old vented cylinder with an unvented one?
Usually yes, and it is one of the most common upgrades we do. It means removing the loft tanks, altering the pipework and fitting the safety and discharge pipework correctly.
Does it work with a system boiler or a heat pump?
Yes to both. A heat pump needs a cylinder with a larger coil, so the cylinder has to be matched to the heat pump rather than reused from a boiler system.
Who is allowed to work on an unvented cylinder?
Only an engineer holding the unvented hot water qualification, often called G3. It is notifiable work, and it is not something to let a general handyman touch.
Which areas do you cover?
Dunfermline and the whole of Fife, as well as South Queensferry and Winchburgh, including Kirkcaldy, Dalgety Bay, Rosyth, Inverkeithing, Cowdenbeath, Glenrothes and Burntisland.
Unvented cylinder work across Dunfermline, Kirkcaldy, Dalgety Bay, South Queensferry and Fife
Based in the heart of Dunfermline, minutes from the M90. Most areas are within a 30 minute drive, and we cover South Queensferry and Winchburgh daily.
- 1Dunfermline
- 2Dalgety Bay
- 3Kirkcaldy
- 4South Queensferry
- •Rosyth
- •Inverkeithing
- •North Queensferry
- •Crossgates
- •Cowdenbeath
- •Lochgelly
- •Burntisland
- •Glenrothes
- •Winchburgh
Book a cylinder visit in Dunfermline and Fife
- Book online
- theheatnetwork.co.uk/book
- Phone
- 01383 660098
- Message us a photo
- hello@theheatnetwork.co.uk
- Office
- Scotia House, 5 Dickson Street, Dunfermline, KY12 7SL
- Hours
- Mon to Fri, 9am to 5pm
