Glow-worm Boiler Repair in Crayford – Radiators Not Heating

We received an urgent call from a homeowner in Crayford who was struggling with a cold home during a chilly snap. Their Glow-worm boiler appeared to be firing up, but the heat wasn't reaching the radiators throughout the property. The customer initially assumed it was an issue with their room thermostat, but after checking the settings, they realized the boiler itself was only producing domestic hot water while the central heating circuit remained stone cold. Upon arrival, our engineer performed a thorough inspection of the Glow-worm unit. We identified that the boiler was failing to switch from the hot water mode to the central heating mode. The fault was traced to a seized diverter valve actuator, which had become stuck in the domestic hot water position due to internal debris and a failing diaphragm. This meant the primary hot water was trapped in the heat exchanger and could not circulate through the heating system, leaving the house completely without warmth.

After isolating the power and gas supply to the boiler, our engineer drained the internal heating circuit to allow for the removal of the faulty component. We carefully disconnected the electrical connections to the diverter valve actuator and unscrewed the housing to inspect the internal seals. The valve cartridge was clearly degraded, causing the obstruction that prevented the pin from moving freely. We replaced the complete diverter valve assembly with a brand-new genuine Glow-worm part to ensure long-term reliability. After installation, we meticulously checked all seals for leaks and refilled the system to the correct operating pressure. Finally, we performed a series of flushes and ventings to ensure no trapped air remained in the system. Once the boiler was powered back on, we monitored the cycle as it successfully diverted flow to the radiators, confirming that the heat transfer was working efficiently across the entire home.