Regular service and maintenance of your boiler can prolong its life by 25%

Service and Maintenance

We service and maintain all the leading brands of boilers including Worcester Bosch, Vaillant, Baxi, Ideal, Glow Worm, Potterton, Vokera, Alpha

Central heating system not as good as it was? Then give us a call. A prompt response from us and quality driven attention to detail ensures a well maintained system.


Call our GAS SAFE engineers and Plumbers on:

FREEPHONE: 0800 0 74 76 78

South Thames Gas carries out repairs on:

  • All types of domestic boiler systems, conventional and combination
  • General repairs on heating systems
  • Water heaters
  • Gas fires
  • Warm air units
  • Underfloor heating
  • Solar Energy systems

Power Flushing

Power Flushing will prevent the build-up of scale and sludge within the system, complementing this service by using inhibitors will provide long lasting protection and enhance the overall efficiency of your boiler.

10 Most Common Boiler Problems

From weird noises to drips and leaks, Boiler Guide counts down the ten most common boiler problems you should look out for:

No heat or hot water – potential causes include broken diaphragms and airlocks, failure of motorised valves, issues with the thermostat or low water levels.

Leaking and dripping – a variety of issues could cause your boiler to leak water. It will depend on where the water is leaking from to determine the cause – however you should never try to fix a leaking gas boiler yourself, always call out a Gas Safe registered engineer.

Strange banging, whistling or gurgling noises – air in the system is a common cause, alternatively it could be that the water pressure is too low or it’s kettling. Imminent pump failure, particularly in older systems, could also be responsible for strange banging noises.

Pilot light goes out – could be a broken thermocouple which is stopping the gas supply, a draught blowing the pilot light out or a deposit built up in the pilot light.

Losing pressure – if your boiler pressure drops too low, your central heating system may not function properly. To check a boiler’s pressure level, simply look at it’s built in pressure gauge – if it’s below 1 you may have an issue. There a number of reasons why this may be happening: a water leak in the system, the pressure relief valve needs replacing or as a result of recently bleeding radiators.

Frozen condensate pipe – condensing boilers have condensate a pipe which transports the acidic water, caused by waste gas, away from the boiler. This usually runs outside into a drain, and because of its location it faces the risk of freezing.

Thermostat issues – if the thermostat is losing accuracy or turning the heating on/off when it’s not supposed to it might be time to invest in a new one. It’s worth making a couple of common sense checks first though, as sometimes these can be easily overlooked. Check your thermostat to ensure it’s in the on position and that it is set to the correct settings i.e time and schedule – it’s always possible that it could have been knocked.

Kettling – hearing a strange rumbling noise similar to when a kettle is boiling? When lime scale or sludge builds up on your boiler’s heat exchanger you can get something called kettling. When these deposits build up in your boiler, they can restrict the flow of water within the heat exchanger. This can overheat the water, causing it to steam and boil (causing the kettle-like sounds).

Radiators not getting hot – you might find that not all of your radiators are getting hot or that only the bottom section is heating up. This can be down to a number of reasons but the two most common are sludge or air build up in the system and unequal distribution of heat.

Boiler keeps switching itself off
– could be low water pressure, a problem with the thermostat or a lack of water flow due to a closed valve, air or the pump not circulating the water in the system properly. We’ve covered each of these issues in more detail above, but if you still can’t identify the cause we recommend calling out a Gas Safe registered engineer to take a look at your boiler.

Quick Quote Form

15 + 2 =


South Thames Gas
62 Railton Road
Herne Hill
SE24 0LF

Email Contact Form