Your boiler and central heating questions answered by experts.
Your boiler and central heating questions answered
As part of Gas Safety Week 2013, we invited Which? members to put their boiler and central heating-related questions to our community of gas engineers.
1. 'How often should I get my boiler serviced?'
John Creasey: 'Your boiler should be serviced every year by a Gas Safe-registered engineer.'
Real Boiler Servicing & Maintenance: 'Boilers should be serviced annually but it's also important to have an annual gas safety check of all the appliances in the property.
'Regulations are always being revised for our safety – an annual service and safety check will make sure you're up-to-date and safe.'
2. What documentation or certificate a gas engineer should be providing after a boiler service is completed?
John Creasey: 'It's normal for an engineer to provide a copy of a service/maintenance checklist at the time of any service.
'Whether the boiler is stripped down will depend on the type of boiler. With modern condensing boilers, it also depends on whether the combustion performance analysis (CPA) readings show any issues or requirements.
'If a modern condensing boiler does require the heat exchanger to be opened, it's normal for a new seal to be required (and a label fitted with the date it was changed).
'All this documentation serves as proof to both parties of what has taken place – everything should be very transparent. Should you have an extended warranty on a new boiler, CPA print-outs and service or maintenance checklists are proof to the manufacturer that you are having the appliance regularly serviced.
'Retain and staple these documents to your boiler log book.'
3. Why does my boiler always break down in winter?
Remloc Plumbing & Heating Ltd: 'Boilers work all year around. They fire for hot water demand whether a combination or heat-only (with hot water tank) boiler.
'Problems in winter could be due to more demand and longer running times but annual safety checks should highlight any issues before they arise.'
John Creasey: 'There is of course the regularly blamed "law" which explains many things! Actually, it's often because the "heating" side of the boiler is not used for about six months and valves get stuck. This can be because of sludge and gunge in the system.
'If people put their heating on for a few minutes once a week throughout the summer, many problems would likely never happen when the cold spell hits.'
4. I have an open vent gas central heating boiler. Central heating is pumped and hot water is provided by gravity feed in summer. Are replacement gas boilers available for these systems?
Remloc Plumbing & Heating Ltd: 'Your system would have to be upgraded to a fully pumped system for both heating and hot water to comply with current building regulations.'
5. How often should I have my heating system flushed?
John Creasey: 'A system should be flushed and cleaned when the boiler is changed.
'If you have a boiler with some life, but sludgy water in the system and cold areas at the bottom of radiators, it may be a course of action to take.'
About our expert trader
John Creasey is a Which? Trusted trader - passing an assessment process to establish that his business has met the high standards set by Which?
John works with domestic gas installations, service and repair and covers the Kingston Upon Thames, North Surrey and West Wimbledon areas.