Heating But No Hot Water?

Do you have heating but no hot water? If so, this article will explain the causes and solutions.

It’s a frustrating scenario when the central heating works, but there’s no hot water available. 

Various central heating components ensure our homes are warm, and our taps and showers provide hot water. 

The heating but no hot water issue can occur when specific components fail or are incorrectly set.

Common Issues & Solutions

Some common issues cause heating, and no hot water solutions are presented.

Thermostat Problems

Modern Boilers have thermostats on the Boiler, which control the heating and hot water. Depending on the Boiler’s age, make, and model, the thermostat could be a dial or digital. 

The thermostat could be switched off, so make sure it’s turned on. If the thermostats are switched on correctly, and you have eliminated the issues below, then it’s possible your Boiler thermostat is faulty and will need replacing by a Gas Engineer.

Timer Issues

Your central heating timer controls when your heating and hot water come on. Heating and hot water are controlled independently. If the heating is switched on, but the water isn’t, your radiators will get hot, but your taps won’t provide hot water.

Ensure your timer is set correctly and that your heating and hot water come on when you want it. 

Consult your manual to ensure the correct setting. You can probably download the timer manual if you no longer have it.

If your timer is set correctly and you’re sure nothing else is causing the issue, your timer may be faulty and need a replacement.

Boiler Issues

There could be an issue with the Boiler itself. Check to see if it’s displaying any fault codes. Cross-reference the code with your manual to determine what the issue is.

You may be able to solve the issue yourself (the manual will tell you what to do). Otherwise, you may need to consult a gas engineer.

Sometimes, a simple reset of your Boiler is enough to solve issues. Try turning it off and switching it back on again.

Boiler Pressure

Inadequate Boiler pressure is the cause of various issues. Ensure your Boiler’s running at the correct pressure, between 1-2 bars. 

If the pressure’s below 1 bar, repressurise your Boiler. If your Boiler’s pressure is above 2 bars, then depressurise it. Your Boiler manual will instruct you on how to repressurise/depressurise your Boiler.

Diverting Valve Issues

The diverter valve is found in Combi (combination) Boilers and determines whether hot water is directed to your radiators, taps, and shower. A faulty Diverter valve is a common cause of heating but no hot water.

If the diverter valve is faulty, it must be replaced by a gas engineer. Do not attempt a repair/replacement yourself.

Issues With The Immersion Heater

While most homes use boilers to provide heating and hot water, some rely on an immersion heater fitted to a hot water cylinder. If the immersion heater fails, then no hot water will be available.

First, check the immersion heater is switched on and the circuit has power going to it (ensure the fuse hasn’t tripped). If the power goes to the immersion heater, check the timer, and it’s still not working, then it could be faulty or not working correctly due to a limescale build-up. 

A heating engineer can undertake a swift replacement.

Airlocks

An airlock in the pipes is essentially a blockage caused by trapped air, which prevents the normal flow of hot water. 

The hot water can’t circulate properly when an airlock forms in the pipes leading to the taps or shower. 

You can resolve airlocks using a hosepipe. Connect a hosepipe to a hot water tap and the other end to a cold water tap. Make sure the connections are secure. You can use duct tape if necessary.

Turn on the hot tap, then open the cold tap fully and run for a few seconds before turning it off.

Check a hot water tap in another room. If hot water is still absent, repeat the process up to half a dozen times if necessary.

If the process doesn’t work or you’re not confident using this method, contact a heating engineer.

The Importance Of Annual Boiler Servicing

Most Boiler issues occur on neglected Boilers, which their owners haven’t appropriately maintained.

Boilers should be serviced annually to ensure they are clean, safe and efficient. 

Boilers serviced regularly are far less likely to present issues such as heating but no hot water.

Servicing is a quick, inexpensive and easy process to ensure you get your Boiler serviced annually by a qualified Gas Safe Registered Engineer.

When To Call A Professional

Most of the issues presented can be solved by following the suggested solutions. If a DIY fix doesn’t work, then it’s time to call a professional Gas Safe Registered Engineer. 

Never attempt to open up a Boiler and undertake internal repairs yourself, gas is dangerous, and you could invalidate your Boiler warranty and home insurance.

If you live in the Essex area and need help with your boiler/heating system, please get in touch with us.