Unvented cylinder servicing and repair in North Devon
I'm George Lane, a Gas Safe engineer. I'm G3 qualified, and I service and repair unvented hot-water cylinders across North Devon.
- Cylinder service £105 including VAT
- £52 when booked with a boiler service
- By a G3-qualified engineer
Prefer to write? Send an enquiry.
George Lane, Gas Safe No. 515374. Fully insured, 25+ years on boilers. I do every job myself, from the first visit to the finished work.
If you smell gas, leave the property and call the National Gas Emergency number, 0800 111 999, before anything else. Once the supply has been made safe, I can come and deal with the appliance.
What my customers say
5.0 from 103 Google reviews for Thames Boilers, my previous business in Kent
Tarka Boilers is new to North Devon, so it has no reviews of its own yet. Every review here is from a customer of Thames Boilers, the heating business I ran in Kent before I moved here.
Read all 124 reviewsAlways great service from George at Thames Boilers. I had a problem with hot water only coming on when we put the heating on .. George arrived when he said he would and was able to diagnose the issue and fix it in a single call out. I really can't recommend George and Thames boilers enough. Thanks again Gavin
Gavin M.Google review, January 2025Customer of Thames Boilers, Kent We had an issue with our hot water and in combination with the Evohome system. George resolved the issue and looked at a few other side issues promptly an easily solving the problem. Would definitely recommend.
Google reviewerGoogle review, June 2025Customer of Thames Boilers, Kent George was absolutely brilliant, and worked like a trooper long into the night on 1st day to ensure we had heating and hot water. He was very courteous and polite and was clear in his quote and the work he undertook. We would thoroughly recommend him. K&J Jones
Checkatrade reviewerCheckatrade review, March 2019Customer of Thames Boilers, Kent Excellent service, all problems have been fixed, full service carried out,in fact more was done than British gas have done over several years. I would recommend Thames boilers without any hesitation. Well done and thank you.
Brian P.Google review, May 2026Customer of Thames Boilers, Kent
- Gas Safe No. 515374Check it on the Gas Safe Register
- 25+ yearson boilers and heating
- G3 qualifiedfor unvented hot-water cylinders
- Fully insuredGeorge Lane trading as Tarka Boilers
I work on Worcester Bosch, Vaillant, Baxi, Ideal, Glow-worm, Potterton and Viessmann. Mains-gas boilers only: I don't work on oil or LPG, and I don't fit new boilers.
Unvented cylinder prices
Every price includes VAT and travel.
Yearly unvented cylinder service
£105including VATStandard gas boiler service and unvented cylinder service on one visit, instead of £210 booked separately
£157including VATFull gas boiler service and unvented cylinder service on one visit, instead of £290 booked separately
£237including VATCylinder repair, all the labour however long it takes
£220fixed labour, including VATCylinder repair: if you decide not to go ahead, you only pay
£105including VAT
Booking both services on one visit brings the cylinder service down to £52, saving £53. Every price includes VAT.
Fixed-price cylinder repair: £220 including VAT for all the labour to get your hot water working again, however long it takes. Parts are priced before they're fitted. Decide not to go ahead, and you only pay £105 for the visit. The £220 includes travel and any return visit to fit a part I've had to order.
A new immersion heater is covered. Replacing a split or failed cylinder, including a failed coil, isn't: that's priced separately and agreed first.
Travel is included in every price. There is no travel charge anywhere I cover.
Every price includes VAT. Repairs are £220 for all the labour, however long it takes, and parts are priced before they're fitted. Decide not to go ahead, and you only pay £105 for the visit. If you're in North Devon, travel is included.
I'm George Lane, a Gas Safe registered engineer (No. 515374), and I'm G3 qualified to service and repair unvented hot-water cylinders across Barnstaple and North Devon. A yearly unvented cylinder service is £105 including VAT, or £52 when I service your boiler on the same visit.
An unvented cylinder is why you can run the kitchen tap without turning someone's shower cold, and why there's no tank in the loft. It also stores a lot of hot water at mains pressure, which is why the work needs a G3-qualified engineer and why the safety valves want checking once a year.
Not sure whether yours is unvented? Describe what's in the airing cupboard when you book and I can usually tell you from that. I do every job myself.
What are the common unvented cylinder faults?
Pressure relief valve dripping. The valve lets water out when the pressure inside the cylinder climbs too high, and the usual cause is a failed expansion vessel. Replacing the vessel is a standard repair.
No hot water, or water that never gets properly hot. Usually a failed immersion heater or cylinder thermostat. Megaflo and most other makes use standard elements, which I can often replace on the same visit.
Poor pressure at the taps. It can be the cylinder, but check the incoming mains first: a supply problem or a failing pressure reducing valve does the same thing.
Banging or rumbling from the cylinder. Usually a failed expansion vessel or scale on the immersion heater. Descaling and a new element aren't part of the yearly service. As a repair, it's the fixed £220 labour price, with any part priced before it's fitted.
A leak from the cylinder or its connections. Corrosion with age, or a failed seal. Where the leak is decides whether it's a seal repair, which the fixed repair price covers, or a split cylinder that has to be replaced, which is priced separately. Book before a drip becomes damage.
What hot water cylinder work do I cover?
Unvented cylinder repair for dripping relief valves, failed expansion vessels, immersion heater faults and hot water pressure that has dropped off.
Megaflo service and repair. Megaflo, made by Heatrae Sadia, is one of the most common unvented cylinders in the UK, and I service and repair it along with the other main makes.
Hot water cylinder repair covering the cylinder, coils, thermostats and controls, including a new immersion heater with its thermostat when those need doing together.
Expansion vessel replacement on boilers and unvented cylinders, with the system brought back up to the right pressure afterwards.
How the job goes, and why
You get the paperwork, not a promise of it: a written record of what I checked, what I tested and what I found. Gas safety certificates come to you by email, ready for a letting agent, an insurer or a buyer's solicitor.
Parts I fit are guaranteed for 12 months, including the labour to put them right, whatever the age of your boiler. The guarantee covers the parts I fit and my work, not the rest of the boiler or system. If sludge caused the fault, I'll still repair it, but that repair isn't guaranteed unless the system has been flushed and a magnetic filter fitted. I'll tell you that before I start, not after.
What is an unvented hot water cylinder?
An unvented cylinder stores hot water at mains pressure. A traditional vented cylinder relies on a cold water tank in the loft for its pressure, so the difference you notice is at the shower and the taps: an unvented system gives mains-pressure hot water all over the house at once.
Makes you'll find in North Devon homes include Megaflo (by Heatrae Sadia), Vaillant uniSTOR, Ariston, Gledhill, Albion and OSO.
Because the water is stored at a much higher pressure than in a vented system, fitting, servicing and repairing unvented cylinders is regulated. Manufacturers ask for a yearly service to keep the warranty, and it's the check that finds a failing safety valve before it matters.
Why does an unvented cylinder need a G3-qualified engineer?
Part G of the Building Regulations requires work on unvented hot-water systems to be done by a competent person, and in practice that means an engineer with the G3 qualification. The reason is the pressure: if a safety device fails and nobody has checked it, the stored water has nowhere safe to go. If a cylinder repaired by someone without the right qualification causes damage, your home insurance may not cover it. My G3 qualification is current.
What's included in a yearly unvented cylinder service?
The service checks every safety device and part that keeps the cylinder working safely:
- Pressure relief valve, the main safety device, tested to confirm it opens and closes at the right pressure
- Temperature and pressure relief valve, discharge-tested to confirm it works
- Expansion vessel, pressure checked and topped up if needed, because a failed vessel is the most common cause of a dripping relief valve
- Expansion relief valve, tested and inspected
- Cylinder thermostat, checked so the cylinder reaches and holds the right temperature without overheating
- Immersion heaters, condition and temperature checked
- Pipework and fittings, inspected for corrosion or leaks
- Discharge pipework, confirmed clear and running safely away from people
- Overall operation, hot water temperature and flow tested
You get a written service record. If a part needs replacing, I tell you what it is and give you a price for the repair at the time, before I touch it.
Frequently asked questions
How much is an unvented cylinder service in North Devon?
A yearly unvented cylinder service is £105 including VAT. A standard gas boiler service and unvented cylinder service on the same visit is £157, instead of £210 booked separately. With the full gas boiler service it is £237, instead of £290. Both prices include VAT. It costs less because it's one visit instead of two, and it can't be combined with any other reduction.
How much does an unvented cylinder repair cost?
£220 including VAT for all the labour to get your hot water working again, however long it takes, including any return visit to fit a part. Parts are priced before they're fitted. If you decide not to go ahead, or it can't sensibly be repaired, you only pay £105 for the visit.
What isn't included in the £220?
Parts, which I price once I've found the fault and only fit once you've approved them. A few bigger jobs are priced separately too: replacing a hot-water cylinder or a boiler's main heat exchanger, anything that means taking the boiler off the wall, flue repairs, replacing radiators, power flushing, fitting a magnetic filter, upgrading controls, and leaks hidden under floors or in walls. If your repair needs one of these, I'll explain why and give you a price, and it doesn't go ahead unless you agree. The £220 is for homes, not commercial systems, and covers the fault you book me for. If sludge caused the fault, I'll still fix it, but that repair isn't guaranteed unless the system has been flushed and a magnetic filter fitted. The full list is in clause 4.2B of my terms and conditions.
How do I know if I have an unvented cylinder?
Look at your hot water cylinder, usually in an airing cupboard or utility room. If there's no cold water tank in the loft, it's probably unvented. An unvented cylinder also has a pressure reducing valve on the incoming cold feed and a temperature and pressure relief valve on the cylinder. If you're not sure, describe what you can see when you book and I can usually tell you.
Does an unvented cylinder need servicing every year?
Yes. The yearly service checks the safety devices and keeps the manufacturer's warranty valid. Unlike a boiler, a cylinder doesn't announce its faults: safety valves wear without any sign, and a relief valve that won't open when it should is dangerous.
Why does my pressure relief valve keep dripping?
The pressure inside the cylinder is going over the valve's limit, and the usual cause is a failed expansion vessel. When the vessel loses its air charge, the expanding hot water has nowhere to go and the valve lets it out. It's a common, straightforward repair.
Do you service Megaflo cylinders?
Yes. Megaflo, by Heatrae Sadia, is one of the most common unvented cylinders in the UK. I also work on Vaillant uniSTOR, Ariston, Gledhill, Albion, OSO and other makes.
Are you qualified to work on unvented cylinders?
Yes. I'm G3 qualified for unvented hot-water cylinders, and Gas Safe registered under number 515374 for the boiler that heats them. You can check the Gas Safe number on the Gas Safe Register.
Why are your reviews from Kent?
Because Tarka Boilers is new to North Devon. The reviews on this site are from customers of Thames Boilers, my previous business in Kent, and each one is labelled.
Unvented cylinder service and repair across North Devon
If you're in North Devon, travel is included in every price.
I do unvented cylinder work across the whole area I cover: Barnstaple, Bideford, South Molton, Ilfracombe, Braunton, Great Torrington, Fremington, Woolacombe, Combe Martin, Lynton, Northam, Westward Ho!, Appledore, Instow, Croyde, Georgeham, Landkey, Swimbridge, Chulmleigh and North Molton.
See unvented cylinder work in Barnstaple, or the areas I cover for the page covering your town.
Other services
- Boiler servicingBook the boiler service on the same visit and the cylinder service is £52
- Central heating repairsFor faults out in the wider heating system
- Landlord gas safety checksAn unvented cylinder in a rented home needs its own yearly service too
Cylinder due a service, or the relief valve dripping? Book George online.
Prices published including VAT. If you're in North Devon, travel is included.
Prefer to write? Send an enquiry.