No Hot Water But Heating Works? Here's Why
If your radiators heat up but you've got no hot water, the cause is often a specific boiler component. Here's what's likely wrong.
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Upfront cost — no obligation It’s a common and frustrating problem: your heating works fine, but there’s no hot water from the taps. Because heating and hot water share some components but not others, this particular combination usually points to a specific fault. This guide explains the likely causes and what to do — most need a Gas Safe registered engineer to put right.
The most likely cause: the diverter valve
In a combi boiler, a diverter valve directs heated water either to your radiators or to your hot taps. When it sticks or fails, it often defaults to the heating circuit — so your radiators get hot but no hot water reaches the taps. A faulty diverter valve is the most common reason for “heating yes, hot water no,” and replacing it is a job for a Gas Safe engineer.
In a combi boiler, a diverter valve directs heated water either to your radiators or to your hot taps.
Other possible causes
Other culprits include a faulty hot water temperature sensor, an airlock or flow issue in the hot water side, or, in systems with a hot water cylinder, a problem with the cylinder’s components or controls. The pattern of the fault — combi versus stored hot water — helps an engineer narrow it down quickly.
Other culprits include a faulty hot water temperature sensor, an airlock or flow issue in the hot water side, or, in systems with a hot water cylinder, a…
What you can check first
Before calling, check the obvious: that the boiler isn’t in a “heating only” mode, that the hot water setting hasn’t been turned down or off on the boiler or controls, and that other taps are also affected (ruling out a single tap problem). If the settings are correct and there’s still no hot water anywhere, it’s time for an engineer.
Before calling, check the obvious: that the boiler isn’t in a “heating only” mode, that the hot water setting hasn’t been turned…
We restore hot water across East London
Gas First fixes hot water faults throughout East London and Essex — most often a diverter valve, which we frequently carry on the van for a same-visit repair. Call us and let us know it’s a “heating works, no hot water” problem so we arrive prepared.
Gas First fixes hot water faults throughout East London and Essex — most often a diverter valve, which we frequently carry on the van for a same-visit…
Frequently Asked Questions
Why do I have heating but no hot water?
In a combi boiler this is most often a faulty diverter valve, which directs water between heating and hot water and can stick on the heating circuit.
What is a diverter valve?
It's the component in a combi boiler that switches heated water between your radiators and your hot taps. When it fails, hot water to the taps is commonly lost.
Can I fix the hot water problem myself?
You can check the boiler's hot water settings and that all taps are affected. Replacing a diverter valve or sensor must be done by a Gas Safe engineer.
Can you repair it on the first visit?
Often yes — a faulty diverter valve is common and we frequently carry the part, so a same-visit repair is likely.
Is it urgent?
It's not dangerous, but you'll have no hot water until it's fixed, so most people want it sorted quickly. We aim to attend the same day.
What Our Customers Say
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“Taps fitted and boiler service, reasonable pricing.”
Lena Uddin | Romford, Essex
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“Cooker installation, gas safety check and boiler check.”
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