A relatively common fault with boilers sees the central heating work with no hot water. In some cases – such as with broken diverter valves – the hot water will only work when the central heating is fired up, whereas in other cases, the hot water will not work at all.
In these situations, the problem will either be with your boiler settings – something you can resolve yourself – or within the internal components of the appliance. If you cannot get your hot water back on by changing your controls, timer and thermostat or by resetting the appliance, then you will have to contact a Gas Safe engineer to get it examined.
Check the controls
It might sound obvious, but frequently, when the central heating works but the hot water doesn’t, then the hot water thermostat control has been turned down to zero. If you haven’t touched the controls for a while, it’s still worth checking that the thermostat is turned up properly – you might have knocked it accidentally.
If there has been a power cut recently, then your boiler may have shut down and will need to be reset. Check that your boiler’s electricity supply is functioning – are the displays properly lit up, or are any bulbs in the boiler illuminated?
You may need to adjust your timer if the electricity supply has been disrupted. You may also need to adjust your timer if the clocks have recently gone forwards or back.
Low flow rates
In cold weather, combi boilers can experience ‘low flow rates’, which may lead you to think your combi boiler has no hot water. The boiler will still be working perfectly; however, the flow of water between the heat exchange will be reduced. You simply have to run the hot tap at a slower rate than you normally would.
Broken diverter valves
Diverter valves switch heat between the hot water and the central heating. When you turn your hot tap on, the diverter valve temporarily shuts off the water supply for your central heating, and when you turn the tap off, the valve reopens and feeds your radiators.
Over time, diverter valves can become degraded and faulty or can be stuck in the wrong position, cutting off your hot water supply. If this is the case, then you will need to arrange a boiler repair – you should not attempt to replace a diverter valve unless you can do so competently!
Turn it off and on again
If all else fails, then try turning the boiler off, waiting for a while, and turning it on again. If your diverter valve is on a separate circuit, then ensure you turn this off and on too.
If you have no hot water from your boiler then it may be worth considering a boiler service plan. 24|7 Home Rescue have a number of boiler and central heating plans that can give you peace of mind. For more information, please click here.
If you have boiler cover with 247 Home Rescue, then we will consider a loss of hot water as an emergency, and will aim to get an engineer to your property within four hours of the time you get in touch with us.
Still having trouble?
Don’t attempt to touch any part of your boiler or central heating system if you’re unsure. Did you know? It’s illegal for anyone to use a gas appliance if they think it’s unsafe.
Call us on 0345 3192 247 and we can help. Our technical team will run through some simple troubleshooting to see if your problem can be resolved on the phone or they can book one of our friendly and knowledgeable Gas Safe Registered engineers to get you back up and running as soon as possible.
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If you find that you regularly have no heating or hot water, read this guide to find out how to avoid boiler breakdowns in future.
247 Home Rescue accepts no liability for any injuries or damages you sustain following the advice on this website. If in doubt, seek professional assistance.