🛡 Gas Safe Reg: 559988 · G3 Certified (Unvented Hot Water) · All Major Brands · Fully Insured & Guaranteed
Why G3 certification matters
Unvented hot water cylinders operate at mains pressure — typically 2.5–4.5 bar. Under Building Regulations Part G, they must be installed by a G3 approved engineer. Appolin Kamdem holds G3 Unvented Hot Water certification — one of a small number of engineers in Greater Manchester legally qualified to install and commission pressurised cylinder systems. An installation by an uncertified engineer does not comply with Building Regulations and will not be recognised by your home insurer.
What Does Unvented Cylinder Installation Involve?
An unvented hot water cylinder is a sealed, pressurised vessel that stores hot water at mains pressure, supplying multiple outlets simultaneously without any loss of pressure or flow. Unlike traditional vented cylinders — which rely on a cold water tank in the loft to supply gravity-fed hot water at low pressure — an unvented cylinder connects directly to the mains and delivers hot water at the same pressure as your cold taps.
Kamdem HomeTech installs, services, and replaces all major unvented cylinder brands across Greater Manchester:
- Megaflo (Heatrae Sadia) — the UK market leader, available in 90–300 litre capacities
- Gledhill Stainless — stainless steel cylinders with lifetime corrosion warranty
- Albion — strong value option with 25-year cylinder warranty
- Vaillant uniSTOR — compatible with Vaillant heat pumps and boilers
- Joule and Telford — reliable alternatives with strong UK distribution
A complete unvented cylinder installation from Kamdem HomeTech includes:
- Pre-installation assessment: incoming mains pressure and flow rate testing
- Cylinder sizing: calculating the correct capacity based on bathrooms, peak demand and recovery rate
- Safe decommissioning and removal of the existing cylinder
- Supply and installation of the new cylinder including all safety components: expansion vessel, pressure reducing valve, expansion relief valve, temperature relief valve, and tundish
- System integration with your system or heat-only boiler
- Full G3 commissioning: testing all safety controls, expansion vessel pre-charge, tundish flow, and thermostat settings
- Building Regulations notification under Competent Person Scheme — handled as part of the installation
- Full commissioning documentation issued on the day
Unvented cylinders require a system or heat-only boiler as the heat source — they are not compatible with combi boilers. If you currently have a combi and want to upgrade, we install a system boiler alongside the new cylinder. Our combi vs system boiler guide explains which configuration suits your property in detail.
What Happens When You Delay?
If you currently have a vented cylinder system supplying low-pressure hot water from a loft tank, the cost of waiting is measured in daily quality of life. Vented systems deliver hot water at typically 0.1–0.3 bar — a fraction of mains pressure. The result is a shower that trickles where it should flow, pressure that drops the moment another tap opens, and hot water that runs out faster than a stored mains-pressure equivalent.
For a growing family in a 3 or 4-bedroom Greater Manchester home, upgrading from a vented to an unvented system is one of the most impactful domestic improvements available — and one that increases property value. An unvented cylinder, correctly commissioned, requires minimal maintenance beyond an annual safety check and carries a cylinder warranty of 25 years on some models.
I installed a 210-litre Megaflo in a 4-bedroom detached in Worsley last spring. The family had been running two combis and still fighting over the shower every morning. Six weeks after installation they sent a message: ‘All four of us showered at the same time this morning and nobody noticed.’ That is what the right system does.
Appolin Kamdem, Gas Safe 559988
Is an Unvented Cylinder Right for Your Home?
| Factor | Requirement | If Not Met |
|---|---|---|
| Mains water pressure | Min 1.5 bar static, 20 litres/min flow rate | An unvented cylinder will not perform adequately. We test this on survey and advise accordingly. |
| Heat source | System or heat-only boiler required | Combi boilers cannot supply an unvented cylinder. A system boiler must be installed alongside it. |
| Space for cylinder | Typically 1800mm × 500–600mm footprint | The cylinder must be in an accessible position with drainage nearby for the tundish discharge pipe. |
Our Process — Simple, Transparent, Reliable
01 — Free Survey
We visit to test mains pressure and flow rate, assess the existing system, confirm cylinder location, and specify the correct model and capacity. No cost, no obligation.
02 — Fixed-Price Written Quote
We provide a written quote specifying the cylinder model, capacity, all safety components, and total installed price. No hidden extras.
03 — G3 Certified Installation
Installation carried out to G3 and Building Regulations standards. All safety valves, expansion vessel, tundish, and pressure reducing valve installed and tested correctly.
04 — Full Commissioning
Every safety control tested: temperature and pressure relief valve function, expansion vessel pre-charge, tundish flow, and correct thermostat set point. Nothing left to assumption.
05 — Building Regs Notification & Documentation
We notify Building Control under the Competent Person Scheme on your behalf. Full commissioning documentation provided on the day.
Why This Matters For You
| Benefit | What It Means |
|---|---|
| Mains-pressure hot water | Full flow to every outlet simultaneously. No pressure drop when multiple showers or taps are in use. |
| G3 legal compliance | Every installation meets Building Regulations Part G and is notified through the Competent Person Scheme. No local authority inspection required. |
| No loft tank required | The cold water tank in the loft can be decommissioned and removed, freeing loft space. |
| Property value increase | A certified unvented system installation is a recognised improvement on property particulars and EPC assessments. |
| 25-year cylinder warranty | Quality unvented cylinders carry warranties of up to 25 years on the vessel itself. |
| Annual check included | Unvented cylinders require an annual safety inspection. We carry this out as part of our Annual Maintenance visit. |
Frequently Asked Questions
What is an unvented hot water cylinder?
A sealed, pressurised storage vessel that stores hot water at mains pressure. Unlike traditional vented cylinders fed by a loft tank delivering low gravity pressure, an unvented cylinder connects directly to the mains and delivers hot water at full mains pressure to every outlet simultaneously.
Who can legally install an unvented hot water cylinder?
Under Building Regulations Part G, unvented cylinders above 15 litres must be installed by a G3 approved engineer. Appolin Kamdem holds G3 Unvented Hot Water certification. An installation by an uncertified engineer does not comply with Building Regulations and will not be recognised by your home insurer.
Can I have an unvented cylinder with a combi boiler?
No. Combi boilers heat water on demand and have no connection point for a storage cylinder. An unvented cylinder requires a system or heat-only boiler. If you currently have a combi, we would install a system boiler and cylinder simultaneously.
What size unvented cylinder do I need?
As a guide: 120–150 litres for 1–2 people; 150–180 litres for 3–4 people with one bathroom; 200–250 litres for families of 4+ with two or more bathrooms. We calculate the correct size based on your actual peak demand during the survey.
How much does an unvented cylinder installation cost in Manchester?
Expect £2,000–£4,000 for a cylinder-only installation into an existing system boiler setup, and £4,500–£7,500 for a full system boiler and new unvented cylinder installation. Contact us for a free survey and fixed-price written quote specific to your property.
Do unvented cylinders require annual maintenance?
Yes. Building Regulations require the temperature and pressure relief valve, expansion vessel pre-charge, and tundish flow to be checked annually by a competent engineer. We carry this out as part of our Annual Maintenance visit. Neglecting the annual check can invalidate the cylinder warranty.
What is a Megaflo?
Megaflo is the brand name of Heatrae Sadia’s unvented cylinder range — the most widely installed brand in the UK. ‘Megaflo’ is often used as a general term for unvented cylinders. We install Megaflo and all other major unvented cylinder brands across Greater Manchester.
Will removing the loft tank affect anything else?
If the loft tank only supplies the existing hot water cylinder, it can be safely decommissioned and removed — standard practice that frees valuable loft space. If the tank also supplies cold water to other outlets, we will survey the pipework before recommending removal and advise on any additional work required.
Related Services
- Central Heating — System boiler installation and heating upgrades
- Boiler Installation — System boiler fitted alongside your new cylinder
- Annual Maintenance — Includes unvented cylinder annual safety inspection
- Combi vs System Boiler Guide — Which boiler type works with an unvented cylinder?