Hot water but no heating? Here's what to do
Finding yourself with hot water but no heating can be a real inconvenience, especially when the weather is chilly.
This issue is more common than you might think, and it can be caused by a variety of factors. The good news is that most of these problems can be resolved with some simple troubleshooting steps.
This guide will help you understand why your heating system might not be working and what you can do to fix it.
We also have a helpful guide if you're experiencing the opposite problem - here's what to do when you have heating but no hot water.
Why do you have hot water but no heating?
When your boiler is supplying hot water, but your radiators remain cold, it’s typically due to an issue within the central heating system. This can happen for several reasons, and understanding the root cause is the first step to fixing the problem.
One of the most common causes is incorrect boiler settings. Boilers have different modes, and if yours is set to 'hot water only,' it won’t send heat to the radiators.
Another potential issue is your thermostat. If it isn’t functioning properly, it won’t signal the boiler to start heating.
Other mechanical issues, such as a stuck or faulty diverter valve, low boiler pressure, or trapped air in the system, can also prevent your radiators from heating up.
Simple changes to make to your boiler settings
Before jumping to conclusions about a major fault, it’s wise to check your boiler settings. Sometimes, a simple adjustment can get your heating system back on track.
Please note you must never use a gas appliance if you suspect it is unsafe. Don't touch any boiler component unless you have the technical know-how.
1. Check if your boiler's set to 'hot water only'
Many boilers come with different operating modes, one of which is 'hot water only.' This mode is useful during the summer when heating isn’t required, but it can cause problems if left on during the colder months.
Start by checking your boiler’s control panel to see if it’s set to 'hot water only.' If it is, switch your central heating settings to a mode that provides both hot water and heating, such as 'heating and hot water' or 'winter mode.'
2. Make sure your boiler's automatic timer is set correctly
Boilers with an automatic timer can sometimes reset after a power outage or due to accidental changes.
If your timer isn’t set correctly, your heating might not turn on when you expect it to.
Double-check the timer settings to ensure they align with your daily routine. Adjust the timings as necessary to ensure your heating comes on when you need it.
3. Check your thermostat
Your thermostat plays a crucial role in maintaining the temperature of your home. If it’s set too low, your heating won’t turn on, even if the boiler is working correctly.
Try increasing the thermostat setting to see if the heating kicks in.
If there’s no response, your thermostat might be faulty or need new batteries. In some cases, a thermostat replacement might be necessary if it’s old or malfunctioning.
4. Find out if your radiators are set independently
In some heating systems, radiators can be controlled independently using thermostatic radiator valves (TRVs).
These valves allow you to adjust the temperature of individual radiators, which can be useful for managing energy use in different rooms.
However, if the TRVs are set too low or turned off, the radiators won’t heat up, even if the boiler is working fine. Check each radiator’s valve to ensure it’s open and set to the desired temperature.
Common boiler faults
If adjusting the settings doesn’t resolve the issue, your boiler might have a fault that needs addressing. Here are some of the most common boiler issues that could be causing your problem.
Your radiators need bleeding and/or balancing
If you find that some radiators are hot while others are cold, it might be due to trapped air in the system or an imbalance in the way heat is distributed.
Bleeding the radiators releases any trapped air, allowing hot water to circulate properly.
Balancing radiators ensures that hot water is distributed evenly throughout your home, preventing some radiators from overheating while others remain cold. For an easy step-by-step guide on how to balance your radiators , see our helpful blog.
Your ignition lead needs replacing
The ignition lead is a critical component that starts the burner in your boiler.
If it’s faulty, the boiler might not be able to ignite the burner, leading to a lack of heating.
This issue requires a professional heating engineer to replace the ignition lead. Working with gas components can be dangerous without the proper knowledge and tools.
Your boiler's burner is blocked
A blocked burner can prevent your boiler from producing enough heat to warm your home.
This blockage is often caused by a buildup of soot or debris within the burner, which can reduce its efficiency or stop it from working altogether.
Regular maintenance and cleaning can help prevent this issue. If your burner is already blocked, it’s best to call in a Gas Safe registered engineer to clean or replace the burner.
You have a faulty combi boiler diverter valve
In combi boilers, the diverter valve is crucial in directing hot water to taps, showers, or radiators.
If this valve becomes stuck or faulty, it might only allow hot water to flow to your taps, leaving you with cold radiators.
Replacing a faulty diverter valve is a job for a qualified heating engineer, as it involves working within the boiler’s internal components.
Your boiler may need replacing
If your boiler is old or frequently breaks down, it might be time to consider a replacement.
Older boilers are generally less efficient and more prone to faults, which can result in hot water but no heating.
Although a new boiler is a significant investment, it can improve your home’s energy efficiency and reduce the likelihood of heating issues in the future.
When to call in a JustFix professional
While some heating issues can be resolved with a few simple adjustments, others require the expertise of a professional. If you’ve tried the above steps and still have hot water but no heating, it’s time to call in a professional heating and gas engineer from JustFix.
Our expert engineers are trained to diagnose and repair a wide range of boiler faults, ensuring your central heating system is working efficiently.
We offer high-quality service at affordable prices, with the convenience of booking online. When you choose JustFix, we’ll match you with qualified local heating engineers who can get your heating back up and running quickly.
Don’t let a faulty boiler leave you in the cold—contact JustFix today for reliable, professional help.
