Boiler Brands We Repair in London

What we do. Fault finding and repair on combi, system and regular gas boilers: no heating, no hot water, intermittent lockouts, leaks, noisy running, and boilers that fire and then drop straight back out. Every gas repair is carried out by a Gas Safe registered engineer.

Our procedure. We take the make, model and fault code on the phone so the van is loaded before we set off. On site we check the gas supply and working pressure, the flue and its seals, the condensate run, system pressure and the electrical controls, then run the appliance up and test it under load before we leave. You are told what needs doing, and what it costs, before anything starts.

Common faults. Ignition lockout from a worn electrode or a dirty flame sensor. Pressure dropping through a weeping valve or a tired expansion vessel. A diverter valve stuck so you get heating but no hot water, or hot water but no heating. Fan and air pressure switch faults. A scaled or blocked plate heat exchanger. Failed PCBs. In cold weather, a frozen condensate pipe.

Did you know. In a cold snap most boilers that look dead are not broken at all. The plastic condensate pipe running outside has frozen and the boiler has shut itself down on purpose. Warm water, not boiling, poured slowly along that outside pipe often brings it straight back.

Health and safety. If you smell gas, do not touch light switches and do not use a naked flame. Open the windows, leave the property, and call the National Gas Emergency Service on 0800 111 999. If a carbon monoxide alarm sounds, get everyone out and call the same number, and 999 as well if anyone is drowsy, breathless or has a headache. Never block an air vent, and never box in or build around a flue terminal.

What we do. Repair, service and re-commissioning of pressure jet oil boilers, internal and external, by OFTEC registered engineers. Burner strip and clean, nozzle changes, pump and photocell work, and combustion set up on a flue gas analyser with the readings recorded.

Our procedure. We start at the tank, because a good number of no heat calls are simply an empty tank or a fire valve that has tripped. Then the filter, the fuel line, the pump pressure, the nozzle, the photocell and the electrodes. The burner is set up on an analyser at the end, not guessed at, and the boiler is left running and tested.

Common faults. A blocked nozzle or filter. A sooted photocell locking the burner out on flame failure. Air in the fuel line after a top up. Water and sludge in the bottom of the tank. A seized or worn pump. Sooted up baffles and back end corrosion on older cast iron units.

Did you know. Servicing matters more on oil than it does on gas. The burner sprays fuel through a nozzle with a hole about the size of a pinhead, so one heating season is enough to change the spray pattern and cost you money on every litre. A yearly service also catches the tank and filter problems that otherwise turn into a lockout in January.

Health and safety. If you can smell oil, or see oil on the ground near the tank, switch the boiler off at the controls and do not try to restart it. A spill is an environmental matter as well as a fire risk. If a carbon monoxide alarm sounds, get everyone out and call 999: 0800 111 999 is the gas emergency line and it is the wrong number for an oil appliance.

What we do. Fault finding on electric boilers and their controls, and on solid fuel and biomass appliances and the wet systems hung off them. Elements, thermostats, contactors, thermal cut outs, pumps, expansion vessels and wiring centres.

Our procedure. On electric, we isolate first, then check the supply and the load at the consumer unit, the thermal cut out, each element in turn and the control wiring, before looking at system pressure and the pump. On solid fuel, we check the flueways, the heat leak circuit and the controls, because a solid fuel appliance cannot simply be switched off when something goes wrong.

Common faults. A thermal cut out tripping, which is nearly always a symptom rather than the fault itself. A failed heating element. Scale in a hard water area, which is most of London. Sticking contactors and burnt terminals. On solid fuel, blocked flueways, a failed heat leak circuit and sooting from burning unseasoned fuel.

Did you know. An electric boiler is close to 100% efficient at the point of use, because there is no flue for heat to disappear up. That does not make it cheap to run. A unit of electricity costs several times a unit of gas, so efficiency and running cost are not the same thing.

Health and safety. Solid fuel produces carbon monoxide, and a working CO alarm in the same room is a legal requirement for a solid fuel appliance in England. Have the chimney or flue swept as often as the manufacturer says. On electric, isolate at the consumer unit before any cover comes off, and never bypass a thermal cut out that keeps tripping. It is telling you something.

What we do. Repair and servicing of instantaneous gas water heaters: no ignition, a pilot that will not stay lit, water that runs hot then cold, and heaters that will not fire on demand. Gas Safe registered, and set up for the gas the heater is actually on.

Our procedure. We check the data badge first to confirm natural gas or LPG, then the flow rate and the inlet filter, the water section and diaphragm, the flame supervision device, the burner and injectors, and the flue and ventilation. The heater is left running and the outlet temperature checked at the tap.

Common faults. A failed thermocouple or flame supervision device, so the pilot drops out. A perished diaphragm, so the heater will not fire when you open the tap. Scale in the heat exchanger, which is the usual cause of hot then cold. A blocked inlet filter starving it of flow. A worn spark generator or piezo.

Did you know. The natural gas and the LPG version of the same water heater are not interchangeable. They use different injectors and different pressures, and running one on the wrong gas is dangerous rather than merely inefficient. Check the data badge before anyone fits a part.

Health and safety. An older open flued water heater takes its air from the room, and must never be fitted in a bathroom or a bedroom. If yours is in a kitchen, the air vent serving it has to stay clear: covering that vent over during a refit is one of the most common dangerous situations we are called to. Fit a carbon monoxide alarm in the same room. If it sounds, leave the property and call 0800 111 999.

What we do. Repairs to vented and unvented hot water cylinders and thermal stores, and to everything that controls them: immersion heaters, cylinder thermostats, motorised valves, expansion vessels, pressure reducing valves, temperature and pressure relief valves and tundishes. Unvented work is carried out by a G3 qualified engineer.

Our procedure. We check the controls before the cylinder, because no hot water is more often a stuck motorised valve, a failed cylinder thermostat or a programmer fault than a failed cylinder. Then incoming pressure, the expansion vessel charge, the relief valves and the tundish, the coil and the immersion. Recovery time is checked at the end so you know it is genuinely fixed.

Common faults. No hot water from a failed cylinder thermostat or a motorised valve stuck shut. A tundish dripping, which is a tired expansion vessel or a failed relief valve. A burnt out immersion heater. Scale on the immersion and in the coil. Slow recovery from a sludged coil. Banging and knocking from a system that is overheating.

Did you know. Water expands by about four per cent when you heat it. In an unvented cylinder that expansion has to go somewhere, and if the expansion vessel has lost its air charge it goes out through the discharge pipe. That is why a dripping tundish is a real fault with a cause, not a quirk to live with.

Health and safety. An unvented cylinder is a pressure vessel, and by law only someone holding the G3 qualification may work on it. Never cap, plug or restrict the discharge pipe from the tundish: it is the safety outlet, and it is the one thing standing between a fault and a stored cylinder of water above boiling point. Have the cylinder checked every year. If the tundish runs constantly, or you hear boiling or banging, turn off the heat sources and call us.

Drop the front flap or look on the underside of the casing. The badge shows the model name and a GC number that begins 47- and identifies the appliance exactly.

Usually on the front of the jacket or around the side near the controls. Take a photo if it is awkward to reach.

Inside the casing door, or on the burner itself. If the boiler is external, the badge is normally behind the front panel.

Tell us roughly how old the boiler is, whether it is a combi or has a hot water cylinder, and what it is doing. That is usually enough to send the right engineer with the right parts.