Unvented Hot Water Cylinder Service
Silver Saints will send you a qualified unvented cylinder engineer to carry out an annual service to your unvented hot water cylinder or Megaflo.
We charge a fixed price of £100+VAT to carry out a service of an unvented hot water cylinder or Megaflo.
4.9 stars from over 1,000 reviews | Fixed-price service | G3 qualified | Same or next day available | Mon to Sat 8am to 5pm | Book Online 24/7
Call 0207 0999 199 Book Online Now
Specific arrival times. A one-hour arrival window is confirmed on every booking.
How much does an unvented cylinder service or repair cost in London?
An annual unvented hot water cylinder or Megaflo service from Silver Saints is a fixed price of £100 plus VAT, with no call-out fee, carried out by a G3-qualified engineer, and Saturday is charged at the same rate. Fault diagnosis and repair, where the cylinder has a problem rather than needing a routine service, is charged at £98 plus VAT per hour, with any parts and the likely cost explained and agreed before the work is done. A service takes around an hour for a typical Megaflo, and a repair depends on the fault, but most diagnosis and a common repair such as recharging the expansion vessel or replacing a relief valve is completed within the hour.
Ready to book?
Call 0207 0999 199 Book Online Now
Why Silver Saints
Here is why London customers have booked Silver Saints for unvented cylinder service and repairs.
- 4.9 stars from over 1,000 Google reviews
- 5 stars on Trustpilot and Checkatrade
- G3-qualified engineers for unvented and pressurised cylinders
- £5 million public liability insurance
- Operating since May 2008
- All work guaranteed against faulty workmanship, with a 12-month guarantee on labour and parts
- A specific one-hour arrival window on every booking
Ready to book? We can come today or tomorrow.
Call 0207 0999 199 Book Online Now
Why an unvented cylinder must be serviced by a G3-qualified engineer
An unvented hot water cylinder stores water under mains pressure, which is what gives the strong flow to every tap and shower in the house at once, and by law any unvented or pressurised cylinder over 15 litres may only be worked on by a G3-qualified engineer. The reason is safety: a pressurised cylinder with a failed safety device does not simply leak, it can discharge under force, so the safety valves, the expansion provision and the discharge route are not optional checks, they are the whole point of the service. Every Silver Saints engineer who attends an unvented cylinder is G3 qualified, and the annual service is also what keeps most cylinder manufacturer warranties, including Heatrae Sadia Megaflo, valid.
Why is my tundish dripping or discharging?
A dripping or discharging tundish is the most common unvented cylinder symptom and it almost always means the expansion vessel air charge has been lost or a safety valve is starting to fail. The tundish is the visible air gap on the discharge pipe near the cylinder, and it should be dry in normal use, so water running from it tells the engineer that the cylinder can no longer absorb the expansion of heated water and is dumping the excess. A Silver Saints G3 engineer will recharge the expansion vessel air pressure or reset the internal air gap, and test the expansion relief valve and the temperature and pressure relief valve to confirm each opens, closes and reseals correctly. Ignored, a discharging tundish in a London property can run continuously and, if a valve fails outright, cause real water damage, which is why it is worth booking promptly.
Common unvented cylinder and Megaflo faults we repair
Silver Saints repairs the full range of unvented cylinder faults, and the symptom usually points to the cause. A drop in hot water pressure or flow is typically a failing pressure reducing valve or a waterlogged expansion vessel. Lukewarm water, water that runs hot then quickly goes cold, or no hot water at all on an electric cylinder usually points to a failed immersion heater or thermostat, while no hot water on an indirect cylinder points back to the boiler or the motorised valve. Water escaping when the system is not in use points to a relief valve not reseating. Silver Saints works on all the major brands, including Heatrae Sadia Megaflo, Gledhill and the other common unvented makes found in London homes, with parts and cost agreed before any repair.
Unvented systems in London properties
Unvented cylinders and Megaflo systems are the standard in larger London homes and high-specification flats, because they deliver mains-pressure hot water to several bathrooms at once without a loft tank, which suits townhouses across Kensington, Chelsea, Westminster and the prime central boroughs, and modern new-builds across the city. That is also why a neglected unvented system is a serious risk in these properties: a failed safety valve or a split cylinder forces water out under pressure and can track through floors and ceilings, so an annual G3 service is cheap insurance against a large repair bill. Older conversions sometimes have the cylinder boxed into an airing cupboard with tight access, which the engineer works around as part of the visit.
Combine your cylinder service with other work in one visit
Because every Silver Saints engineer is multi-trade, an unvented cylinder service or repair can be combined with other work in the same visit with no second call-out fee. Customers commonly pair a cylinder service with an annual gas boiler service, a Landlord Gas Safety Record, bleeding or balancing radiators, or sorting low system pressure on the heating side, all booked under one appointment.
Frequently asked questions about unvented cylinder service and repair in London
Can you service or repair my unvented cylinder today in London?
Silver Saints offers same-day and next-day unvented cylinder and Megaflo appointments across London subject to availability, so call 0207 0999 199 or book online at bookings.silversaints.com and the team will confirm the earliest G3 engineer slot for your postcode.
How much does an unvented cylinder service or repair cost in London?
An annual unvented hot water cylinder or Megaflo service from Silver Saints is a fixed price of £100 plus VAT with no call-out fee, and fault diagnosis and repair is charged at £98 plus VAT per hour.
Why is my tundish dripping or discharging water?
A dripping or discharging tundish usually means the expansion vessel air charge has been lost or a safety valve is failing, and a G3-qualified engineer needs to recharge the expansion provision and test the relief valves, because a tundish should be dry in normal use.
Why has my unvented hot water pressure dropped?
A drop in unvented hot water pressure or flow is typically caused by a failing pressure reducing valve or a waterlogged expansion vessel, both of which a Silver Saints G3 engineer can diagnose and repair.
Do you service and repair Megaflo cylinders?
Yes, Silver Saints services and repairs Megaflo cylinders, which are a popular brand of unvented hot water cylinder, along with Gledhill, Heatrae Sadia and the other common unvented makes in London homes.
Does an unvented cylinder have to be serviced by a G3 engineer?
Yes, by law any unvented or pressurised hot water cylinder over 15 litres may only be serviced or repaired by a G3-qualified engineer, and every Silver Saints engineer who attends an unvented cylinder holds that qualification.
How often should an unvented cylinder be serviced?
An unvented hot water cylinder should be serviced once a year to check the safety valves, the expansion provision and the discharge route, and annual servicing is also required to keep most manufacturer warranties valid.
Which London areas do you cover for unvented cylinder work?
Silver Saints services and repairs unvented cylinders across all 32 London boroughs and the City of London, from inner London out to boroughs such as Bromley, Croydon, Ealing and Richmond, plus the adjacent TW, KT, CR and BR postcodes.
Customer Reviews
Our customers across London rate us highly on the main review sites:
- Google Customer Reviews
- Trustpilot Customer Reviews
- Checkatrade Customer Reviews
- Yell Customer Reviews
Silver Saints unvented cylinder service and repairs in London
Silver Saints unvented hot water cylinder service and repairs is a G3-qualified service for pressurised hot water cylinders and Megaflo systems in London homes, where the annual service checks and recharges the expansion vessel or air gap, tests the expansion and temperature and pressure relief valves, checks the discharge pipe and tundish, inspects the cylinder, controls and pressures and completes a service record, while a repair diagnoses and fixes faults such as a dripping tundish, lost hot water pressure, a failed immersion or thermostat, or a leaking valve. It covers all 32 London boroughs and the City of London plus the TW, KT, CR and BR postcodes, across townhouses, period conversions and modern flats, is carried out Monday to Saturday 8am to 5pm, and is a fixed price of £100 plus VAT for the annual service with repairs charged at £98 plus VAT per hour. Silver Saints is rated 4.9 stars on Google from over 1,000 reviews and is fully insured. To book, call 0207 0999 199 or visit bookings.silversaints.com.
The 15 Point Fixed Price Unvented Hot Water Cylinder Service Includes:
- Removal and cleaning of any filters or strainers
- Checking the integrity of the cylinder for leaks or damage
- Checking the air charge pressure in the expansion vessel and topping up if necessary, or checking the operation of a float-operated valve in the cistern
- On systems with an internal expansion facility, resetting the expansion gap while testing the temperature and pressure relief valve
- Manually operating the expansion relief valve to confirm it opens, closes and reseals correctly
- Manually operating the temperature and pressure relief valve to confirm it opens, closes and reseals correctly
- Checking the discharge pipes for blockages or obstructions and checking the termination position
- Checking storage and delivery temperature settings and the operation of controls and motorised valves
- Checking the sacrificial anode
- Where accessible, checking heat exchangers in hard water areas
- Checking the water pressure downstream of the pressure reducing or limiting valve
- Checking water pressure and flow rates at terminal fittings
- Checking and cleaning flow diffusers on taps where fitted
- Explaining the work carried out to the customer
- Completing the service record
Unvented Cylinder Service for £100+vat
Unvented Hot Water Cylinder Repairs
Silver Saints will sent you a qualified London boiler engineer to investigate and repair any faults to your unvented hot water cylinder or Megaflo.
We charge £98+vat per hour for unvented hot water cylinder fault diagnosis repairs.
The most common faults with unvented hot water cylinders our London boiler engineers can repair include:
- Hot Water pressure drops | Luke Warm Water | Boiler on but no hot water
- Hot water only lasts a few minutes | Water escaping through tundish |
- Water escaping when not in use | Water not heating up when electric element is on
7 Reasons to book a Silver Saint's London Boiler Engineer:
- Professional & Experienced. All our London boiler engineers come from multi-trade backgrounds, have decades of experience with boiler repairs, communicate well and understand the importance of customer service.
- Quick Response Times. We can usually offer you Same-day or Next-day appointments.
- Specific Arrival Times. We agree a 60 minute window of arrival time. So no need to wait in all day.
- Silver Service from Booking to Billing. All our work is delivered with unmatched Silver Service.
- Six Day Service. We offer appointments from 08:00-17:00 Monday to Saturday at the same great value rates.
- We've got London Covered. We cover all London as well as TW, KT, CR, BR postal codes.
- All our Work is Guaranteed & Insured. We offer a 12 month guarantee on all labour and parts we supply.
Unvented hot water fault diagnosis & repairs for £98+vat per hour.
Meet the Saints
Martin 
Luke 
Stan 
Patrik 
Jeremy 
Raymond 
Mick 
Dave 
Lukas 
Graham 
Danny 
Jerry 
John 
Leon 
Simone 
Deon 
Stefan 
Paolo 
Juan 
Cosmin 
Eugen 
Paul 
Christo 
Kieran 
Adrian 
Pieter 
Sandor 
John P 
Oleg 
Szymon 
Posted on Google
