Expansion vessel and charge pressure
The vessel absorbs the expansion of water as it heats. If the charge pressure is wrong or the vessel has failed, pressure builds up in the cylinder — I test and recharge or replace as needed.
G3 qualified Tiverton
Unvented cylinder service and repairs in Tiverton
An unvented hot water cylinder is a pressurised system that delivers mains-pressure hot water throughout the house without a separate cold water tank. It needs to be serviced annually by a qualified engineer. That's not just good practice; it's a Building Regulations requirement under Part G3. I'm G3 qualified to service, maintain and repair unvented hot water cylinders across Tiverton and the surrounding Mid Devon area.
Unvented cylinders are pressurised systems. Building Regulations Part G3 requires a G3-qualified engineer, which is what I am.
Gas Safe25+Years experience
5.0
Reviews from my previous Kent business- Gas Safe registered
- G3 qualified for unvented cylinders
- £2m public liability insurance
- 25+ years of experience
- Twelve months’ cover on any boiler part I fit
Happy to confirm Gas Safe registration and insurance details when we arrange your visit.
What a G3 service includes
Safe pressure, valid warranty, hot water you can rely on
I'm G3 qualified to service, maintain and repair unvented hot water cylinders. I cover Tiverton and the surrounding Mid Devon area including Bampton, Cullompton, Crediton, Halberton and Bickleigh. I work on Megaflo, Telford, Gledhill and Heatrae Sadia cylinders, along with similar makes from other manufacturers.
Pressure relief valve (PRV)
Tested to confirm it opens at the correct pressure and reseals cleanly. A PRV that weeps constantly is failing and needs replacing.
T&P valve — the temperature and pressure relief device
This is the critical safety device — it opens to release water if the cylinder overheats or pressure spikes. I test it and check the discharge pipework is correctly installed and unobstructed.
Thermostat and overheat thermostat
Both are checked to confirm they cut out at the right temperatures.
Immersion heater and wiring (where accessible)
Inspected for condition and correct installation.
Overall condition check
I inspect the cylinder, connections and any motorised valves for signs of corrosion, weeping joints or wear.
Cylinder makes
Cylinder makes I work on
Megaflo (Heatrae Sadia)
One of the most common unvented cylinders found in UK homes.
Telford
Stainless steel cylinders — servicing and repair work covered.
Gledhill
Including StainlessLite and older models.
Heatrae Sadia
Megaflo and other models in the range.
Joule
Covered — call to confirm your specific model.
Other mainstream makes
If your cylinder isn't listed, call and I'll confirm whether I can help.
Repairs
Tracking down the fault before any parts go in
Lukewarm water, a steady drip from the discharge pipe on the outside wall, or pressure that won't hold — whatever the symptom, I work out what's behind it before I suggest spending a penny on parts. Anything I supply and fit carries a twelve-month guarantee.
Cylinder faults can sometimes look like boiler or control faults. I'll check the whole picture, from the programmer and motorised valve through to the thermostat and boiler, so you know where the problem actually is.
I don't fit brand-new cylinders or boilers — my work here is servicing and repairing the unvented systems you already have in place.
Questions
Unvented cylinder questions homeowners ask
Does my unvented cylinder really need an annual service?
Under Building Regulations Part G3, pressurised hot water cylinders must be installed, maintained and repaired by a qualified person holding a G3 certificate. Most manufacturers also require annual servicing to maintain any warranty. More practically, the safety devices on a cylinder are there to prevent it from failing catastrophically — they need to be tested regularly to confirm they're working.
What does G3 qualified mean?
G3 is the Building Regulations qualification required to work on unvented hot water systems. Engineers without it are not legally permitted to carry out this work. Always check your engineer holds a current G3 qualification before booking.
My cylinder is making a popping or rumbling noise — what does that mean?
Noise from an unvented cylinder often points to limescale build-up on the immersion heater element, or an expansion vessel that has lost charge. Both are worth investigating. Call me and describe what you're hearing and I'll give you my assessment.
The pressure relief valve keeps dripping — is that a problem?
Yes. A PRV that weeps steadily or discharges regularly is either responding to genuinely high pressure (which needs investigating) or has failed and needs replacing. It's not something to leave — a continuously weeping PRV can lead to water damage and indicates the system isn't operating correctly.
Can you repair cylinders, not just service them?
Yes. If I find a fault during a service, or if you call because something specific has stopped working, I carry out repairs on the makes listed above. This includes replacing expansion vessels, PRVs, T&P valves, thermostats and immersion heaters.
How long does a cylinder service take?
Usually between 45 minutes and an hour and a half, depending on access and the condition of the system.
Book your unvented cylinder service in Tiverton
Call me on 01884 212409 to arrange an appointment. I cover Tiverton (EX16) and the surrounding Mid Devon area. If you're not sure whether your cylinder is due for a service or you have a specific fault, describe it when you call and I'll let you know whether it's something I can help with.