Boiler repair, servicing and heating care in London

A dead boiler in January is the call every landlord dreads. GEM keeps heating systems ahead of that moment with planned servicing, honest diagnostics and Gas Safe registered engineers who work across the boiler brands common to London housing stock.

We install and commission new boilers where replacement is the right answer, but we are equally comfortable extending the life of a sound system: powerflushing, radiator balancing, replacing failed valves and modernising controls with room-by-room thermostats that cut running costs for tenants.

Gas safety and the annual CP12

Every rented property with gas appliances needs a Landlord Gas Safety Record, commonly called a CP12, renewed every twelve months by a Gas Safe registered engineer. For subscribers, the renewal date is tracked and reminded through the portal and the certificate is a bookable add-on we arrange, chase and file, so compliance never depends on a diary reminder and the certificate lands in the property file where your agent and your renewal process can find it. Tenant access is the part that derails most CP12 renewals, so we handle the appointment-making and the reminders as well as the inspection itself.

Repair or replace: how we call it

The honest answer to an ageing boiler is arithmetic, not instinct. We weigh the fault against parts availability, the repair history we hold for the appliance and the efficiency gap to a modern condensing unit, then put the repair price next to the replacement price so the decision is yours with full information. Roughly, a boiler past its mid-teens with a failed heat exchanger rarely justifies repair; a ten-year-old unit with a faulty diverter valve usually does.

Getting more from the system you have

Cold spots, banging pipework and long warm-up times are usually circulation and control problems rather than boiler failures. Powerflushing clears the magnetite sludge that strangles radiators, balancing evens out flow across floors, and modern controls, from smart thermostats to thermostatic radiator valves, let tenants heat the rooms they use instead of the whole envelope. These are afternoon jobs that change how a home feels through winter.

Hot water deserves the same attention as heating. We maintain and replace vented and unvented cylinders, immersions and the combi conversions common in smaller flats, and we will tell you when a cylinder system is the wrong fit: a one-bathroom flat rarely needs stored water, while a family house with two showers running at once nearly always does. Unvented cylinders are pressurised vessels, so their safety controls are checked at every annual service.