Your Diverter Valve is Sticking
The diverter valve is a part inside the boiler that switches between hot water for your taps and the central heating. Valves can jam or become ‘sticky’, preventing them from working properly. If a diverter valve sticks, you may find that you only have heating or only have hot water. In some circumstances your boiler may stop working altogether. A common cause of valve failure is sludge in the system.
An installer can easily replace a faulty diverter valve but should always investigate the problem and find out what happened. Because there are so many models of boiler and exact types of valve, your installer will probably need to collect the part from a boiler merchant.
Your Flow Switch Isn’t Working
Flow switches are a major part of a combi boiler and would be familiar to a competent installer. The flow switch’s job is to sense when you turn on a hot-water tap and the boiler. Very occasionally, they can become blocked and need replacing.
If your combi boiler is running your central heating successfully but not producing hot water, the flow switch or diverter valve may be faulty. An installer will be able to tell you which of these items needs replacing, or if something else is causing the problem.
You Should Upgrade Your Radiators with TRVs
TRV is short for Thermostatic Radiator Valve. This is an adjustable valve connected to each radiator that allows you to alter the temperature of each room by regulating the flow of hot water to each individual radiator. The valve regulates the flow depending on how hot or cold the room is. Your installer should assess the condition of your radiators and fittings and may recommend you use TRVs.
TRVs are a simple way of adjusting the temperature in each individual room. Also, if you have rooms that you are not using, TRVs give you the option to not heat them at all, but they still provide low-temperature frost protection (this is the setting indicated by the snowflake symbol on the valve).