It’s a chilly evening, you switch on the heating, and… nothing. The radiators stay cold, but the hot water is running perfectly. If this sounds like you, you’re not alone. Radiators not working but hot water is one of the most common issues homeowners face and while it’s frustrating, it’s usually fixable.
In this guide, we’ll explain why your radiators might not be heating, what you can try yourself and when it’s time to call in the experts.
Why Are My Radiators Not Working but Hot Water Is?
When you have radiators not working but hot water is, it can feel confusing. After all, the boiler is clearly running if the hot water works, right? The thing is, your boiler has separate components for hot water and central heating. That means one part can fail while the other still works fine.
Here are the most common reasons:
1. Heating Controls Set Incorrectly
Before worrying about bigger issues, double-check your boiler and thermostat. Sometimes, the heating is set to “hot water only.” If your controls aren’t on the right setting, you’ll notice radiators not working but hot water is.
2. Trapped Air in the Radiators
If only some radiators aren’t warming up, air pockets could be the cause. Air prevents hot water from circulating properly. The classic sign is a radiator that’s warm at the bottom but cold at the top.
3. A Stuck Diverter Valve
The diverter valve directs hot water to either your taps or your radiators. If it sticks in the hot water position, you’ll end up with radiators not working but hot water is. Unfortunately, this isn’t something you can fix yourself it usually needs a heating engineer.
4. Faulty Circulation Pump
Your pump pushes hot water around the system. If it fails or gets stuck, the boiler may still heat water for your taps but not push it into the radiators. A telltale sign is radiators that feel lukewarm or noisy.
This is another case where professional help is needed.
5. Thermostat Problems
A faulty thermostat or timer can trick your system into thinking no heating is required. If you’re experiencing radiators not working but hot water is, check your thermostat batteries, settings, and position in the house.
6. Sludge or Blockages
Over time, radiators and pipes can fill with sludge rust, dirt, and limescale that stop water flowing properly. If you notice uneven heating or cold spots, sludge could be why your radiators not working but hot water is.
The usual fix is a power flush, carried out by a professional.
7. Boiler Faults
Sometimes, the boiler itself is the culprit. Low pressure, faulty components, or error codes can all mean your hot water works fine but your radiators don’t. If the pressure gauge is below 1 bar, try repressurising the system. If you’re unsure, call an engineer.
What You Can Try Yourself First
Before you pick up the phone, there are a few easy checks you can do:
Make sure the heating controls are set correctly (not just hot water).
Check boiler pressure is between 1–2 bars.
Bleed radiators that are cold at the top.
Reset the boiler if an error code is showing.
If after this you still have radiators not working but hot water is, it’s time to call a professional.
Why You Shouldn’t Ignore the Problem
Cold radiators aren’t just uncomfortable. If your system is struggling, it could be wasting energy and costing you money. Issues like a stuck valve or pump failure won’t fix themselves and leaving them too long can lead to bigger, more expensive repairs later.
So if you’ve got radiators not working but hot water is, it’s best to get it checked sooner rather than later.
Get Expert Help Today
At some point, DIY fixes won’t cut it. If you’re still stuck with radiators not working but hot water is, our team of qualified heating engineers can help. We deal with this problem every day and know exactly how to get your system back up and running whether it’s bleeding radiators, fixing a diverter valve, replacing a faulty pump, or clearing sludge with a power flush.
Regular servicing is the best way to prevent problems like radiators not working but hot water is. If it’s been over a year since your last boiler service, now’s the time to book.
Call us today or book online to get your radiators heating properly again. Don’t put up with a cold house while your hot water works overtime. Let’s fix it before it gets worse.
Radiators aren’t working but hot water is?
Call us today!
Our experienced heating engineers can quickly diagnose the issue whether it’s trapped air, a stuck diverter valve, or a faulty pump and get your radiators heating properly again. Don’t suffer in a cold home while your boiler works overtime; let us bring the warmth back fast.