Megaflo Boiler Repairs London
Over 20+ years experience with Megaflo Boilers
Insurance approved
90% repaired on the same day
0203 695 3137
How we can assist with your Megaflo Boilers
- Emergency Boiler Repairs
- Boiler Service
- Landlord Safety Certificates
- New Boilers Installations
- Leaking & Noisy Boilers
- Power Flushes
Boiler Repairs R Us are experienced in handling all types of Megaflo Boilers. We can also assist with all gas, condensing, combi boiler installations and upgrades. All our plumbers are Gas Safe Registered so you can be assured all our work is carried out within the required regulations. So for complete customer satisfaction call us on 0203 695 3137 to get your Megaflo Boilers repaired today!
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Trusted, reliable boilers repair & install specialists.
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Megaflo Repair Help Centre
Common Megaflo unvented cylinder problems, safe checks, and when to call a qualified unvented engineer.
We specialise in Megaflo unvented cylinder repairs across London.
Qualified engineers for unvented cylinders for safe diagnosis, repair and testing.
24/7 call handling with London wide booking and fast triage.
Megaflo Repairs London (Unvented Cylinder Qualified)
No hot water, low pressure, tundish dripping, leaks, or an immersion issue? Tell us your cylinder model (if known), what is happening, and your postcode and we will advise the quickest safe next step.
📞 Call 0203 695 3137
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Fast triage: Megaflo model and litre size (if visible), whether you have any hot water, whether cold water pressure is normal at the kitchen tap, and whether the tundish is dripping.
⚠️ Safety First (Unvented Cylinder)
Water leaking from the safety discharge pipe or tundish? This can indicate overpressure or overheating. If water is continuously discharging, turn off the heat source (boiler) and call an engineer.
Electrical burning smell or immersion fault? Turn off the immersion spur and call an engineer.
Do not tamper with unvented safety valves. Unvented cylinders have critical safety components that must be tested and replaced correctly.
Jump to: Symptoms · Low Hot Water Pressure · No Hot Water · Tundish Dripping & Leaks · Repair or Replace
Common Megaflo Problems
| Symptom | Most Likely Cause | What To Do |
|---|---|---|
| No hot water at all | Boiler not heating cylinder, immersion not working, programmer, thermostat or motorised valve issue | Check programmer is on for hot water. If heating works but hot water does not, call an engineer. |
| Hot water runs out quickly | Thermostat set low, immersion not heating fully, blending valve issue, undersized cylinder | Check thermostat settings, then book a diagnosis. |
| Low hot water pressure | Incoming mains issue, pressure reducing valve fault, strainer blocked, scale build up | Compare cold kitchen tap pressure vs hot. If cold is also low it may be mains. If only hot is low, call an engineer. |
| Tundish dripping or water discharging outside | Relief valve lifting, expansion vessel issue, overpressure or overheating | Turn off boiler heat and call an engineer. Do not ignore continuous discharge. |
| Leaks around cylinder | Valve seep, pipework joint, tundish issue, expansion vessel failure | If safe, isolate water and call an engineer for diagnosis. |
| Immersion heater not working | Failed immersion element, thermostat, spur/fuse issue, wiring fault | Check the immersion spur is on. If there is burning smell or tripping, turn it off and call an engineer. |
Low Hot Water Pressure (Megaflo)
What is happening: Megaflo is mains fed, so you should normally have strong hot water pressure. If hot pressure is weak but the cold kitchen tap is strong, it often indicates a valve, strainer or pressure reducing valve issue on the unvented set.
What to check safely: Compare cold pressure at the kitchen tap versus hot pressure. If cold is also low, it may be a mains supply issue. If only hot is low, book an engineer.
No Hot Water (Megaflo)
Common causes: Boiler is not heating the cylinder, motorised valve fault, programmer not calling for hot water, cylinder thermostat fault, immersion heater fault.
What to try: Check the programmer is set to hot water “On” or “Auto”. If your heating works but hot water does not, it is often a valve or control issue that needs testing.
Tundish Dripping, Leaks and Discharge Pipe Water
Tundish dripping: If you see water dripping from the tundish, it can indicate expansion or pressure issues. Continuous dripping should not be ignored.
What to do: Turn off the boiler heat source and call an engineer. Do not attempt to cap or block discharge pipework.
Why These Issues Are Common in London Homes
- Hard water: scale can affect valves, strainers and mixing valves, reducing hot water flow.
- High water demand: larger households expose cylinder sizing and recovery issues.
- Older installs: expansion vessels and PRV sets wear and need periodic replacement.
Megaflo Models and Install Types We Work With
- Megaflo unvented cylinders: various litre sizes and install configurations
- System boiler with cylinder: setups feeding Megaflo
- Immersion heater systems: single or dual immersion
🔧 Hot Water Issues Plus Heating Problems?
If your Megaflo is heated by a boiler and you have boiler lockouts or cold radiators as well, it may be a system circulation or control issue. If radiators are cold at the bottom, a power flush can improve circulation. Power flush guide.
Repair or Replace?
Unvented cylinders often last 10 to 20 years depending on water quality and maintenance. Many issues are repairable, such as valve sets, immersions, thermostats, blending valves and expansion vessels.
If your system is older and you are repeatedly losing hot water, we can advise whether repair or replacement is more cost effective.
Servicing (Unvented Cylinder)
Unvented cylinders should be serviced periodically to ensure safety components operate correctly. If you need a service, call us and we will advise the right maintenance schedule for your installation.
Landlords and Lettings
If your property has gas appliances, stay compliant with our Gas Safety Certificate (CP12) service. For hot water system issues in rentals, we can diagnose controls, valves and cylinder faults.
London Wide Coverage
We repair Megaflo systems across all London boroughs.
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Book Your Megaflo Repair
Engineers available across London. Speak to our team for safe next steps.