Imagine this: after a long day, you’re looking forward to a soothing bath, or perhaps you’re eager to tackle scrubbing the pots and pans so you can unwind for the evening. But when you turn on the tap, there’s no hot water—frustrating, right? This common issue can massively impact your daily routine. Fear not – help is just a call away!
If you are dealing with no hot water coming out of your tap, this guide will walk you through potential causes and solutions to help you get back to soaking in the tub as quickly as possible.
Common Causes Of No Hot Water
When a hot tap is turned on, but no hot water runs out, immediate attention is needed, as the problem can stem from several causes, ranging from simple to more complex. Here are the most common causes:
Boiler Issues
A gas combi boiler, the most common type of boiler in UK homes, is made up of several key components, each playing a vital role in its efficient operation. The main elements include:
- The Gas Burner: Responsible for heating water on demand whenever hot water is needed.
- The Heat Exchanger: This component works in tandem with the gas burner, transferring heat to the water, which is then circulated through taps and radiators to provide hot water and heating throughout the system.
- The Thermostat: A critical part of the heating process. It monitors and regulates the water temperature, ensuring consistent heat levels for both your home and hot water supply.
Simply put, the heating cycle of a combi boiler begins with a signal sent from the tap (or heating request) to the boiler, igniting the gas burner. Once the heat from the gas burner is transferred to the water by the heat exchanger, the hot water is circulated to its destination – either to the radiators for heating a room or to the taps for hot water.
A problem or fault with any of these key components of a boiler could cause a tap to yield no hot water when turned on.
Incorrect Boiler Pressure
High or low boiler pressure can also stop hot water from reaching the tap.
Low water pressure: The optimal range for boiler pressure is 1-2 bar. The pressure gauge on the front panel of your boiler will display the boiler’s pressure so you can check. The pressure needs to be balanced at this level in order for the boiler to activate and heat water. If the pressure is too low, the boiler may not detect water flow, preventing it from igniting the burner and heating the water. Low water pressure can also result in water trickling slowly, which might not allow enough time for the heat exchanger to effectively heat the water.
High water pressure: If water is pushed through the heating system too quickly, the heat exchanger may not have enough time to do its job properly, leading to lukewarm or chilly water at the tap. Plus, persistent high pressure can put stress on the boiler and its internal components, potentially leading to malfunctions that prevent hot water production.
Plumbing Problems
Sometimes the problem is less complex so always look for leaks or blockages in the system. Clogged pipes will inhibit the flow of water, as can leaks which reduce water pressure.
Broken Tap Mixer Valve
A tap mixer valve is the mechanism within a mixer tap which blends hot and cold water from two supply pipes to deliver water at the desired temperature therefore, if the mixer valve is broken, it can affect hot water by:
- Hot water blockage: If the valve is damaged or clogged with debris, it may restrict or completely block the flow of hot water, preventing it from mixing with the cool water or reaching the tap altogether.
- Imbalanced mixing: A faulty valve may mix the water incorrectly, allowing only cold water to flow out of the tap, even if the hot water supply is working properly.
- Internal seal damage: Broken seals or worn components inside the valve can cause leaks or allow cool water to backflow into the hot water line. This can reduce the temperature or pressure of the water coming out of the tap.
- Complete failure: If the mixer valve is completely broken, it may fail to deliver any water from the hot water supply, leaving only cold water running.
At Maintracts Services, our experienced plumbers and heating engineers are here to help. Contact us today to quickly resolve your hot water issues.
DIY Troubleshooting Steps
If you consider yourself a handy person and feel confident in having a go at fixing common minor issues relating to no hot water emitting from your tap, here are some DIY troubleshooting tips for you to follow to try and fix the issue before reaching professional help.
1
Check other taps
Turn on other hot water taps in your home to see if they also lack hot water. If all taps have no hot water, the issue is likely with the boiler or plumbing system. If it’s just one tap, the problem is isolated to that fixture (e.g. a clogged or faulty tap).
2
Inspect the boiler
Ensure the boiler or water heater is switched on and working correctly. Check for error codes on the display panel, if applicable.
Verify the pressure gauge is within the recommended range (usually between 1.0 and 2.0 bar for combi boilers).
Confirm that the pilot light is on (for older boilers) or that the system is actively heating water.
If the pressure is too low, top it up using the boiler’s filling loop. Reset the boiler if an error code flashes indicating that it is required.
3
Check the mixer tap or valve
Remove the tap aerator and clean it to clear any debris or limescale. Check the mixer valve (if your tap is a mixer tap) for blockages or damage.
Clean out any debris or limescale build-up inside the valve. If that doesn’t work, the internal cartridge may need replacing. If the problem persists, call a professional to repair or replace the entire tap mixer.
4
Ensure there’s no airlock in the system
Turn on the hot tap and a cold tap (ideally close together, like in the kitchen sink). Place a hose between the two taps to allow cold water to flow into the hot water pipe and push out any trapped air. This will help unblock any air locks that are preventing the water to flow freely.
5
Check for frozen pipes (in winter)
Inspect pipes leading to your boiler or water heater for signs of freezing (e.g. frost or bulging).
Feel the pipes to check if they’re unusually cold. If so, gently warm frozen pipes using a hairdryer or a hot towel, starting from the tap end and working back towards the boiler.
6
Look for leaks or blockages
Inspect visible pipes for leaks, especially around the joints. Check stopcocks or isolation valves to ensure they are fully open and look for debris in the tap or pipes.
Tighten loose joints or fittings if possible. Remove and clean blocked sections (e.g. the tap head).
7
Test the thermostat settings
Check your boiler or water heater’s thermostat settings to ensure the temperature is set high enough to heat water.
If the thermostat is accidentally turned down or malfunctioning, it may prevent water from heating.
8
Test the hot water pressure
Turn on the hot tap and assess the water pressure. If it’s low, the problem might be with your water supply.
Check the boiler’s inlet filter for blockages. If blocked, clean the filter if its accessible, or contact your water supplier if it’s a mains issue.
Topping up water pressure is quite a simple short-term fix, but long-term it’s important to find the underlying cause of the issue.
When To Call A Professional
Whilst there are things that a keen DIYer could do to try and diagnose (and possibly fix) the lack of hot water flowing from the hot water tap, we always recommend enlisting the help of a professional heating engineer or plumber to carry out the work. Particularly if you are dealing with:
- Persistent boiler error codes
- Leaks in hidden or inaccessible pipes
- Gas-related problems such as the pilot light or burner not igniting
- If there’s no water flow at all (hot or cold)
- Unusual noises coming from the boiler
- If you suspect a gas issue
Prevention Tips For The Future
In order to avoid being without hot water again, we recommend scheduling in regular boiler servicing in the same way you schedule in an MOT and service for your car! It’s particularly important to keep your boiler running at its best to ensure you are not paying for heat that you are not benefiting from, or water that isn’t hot.
Insulating pipes to prevent freezing in winter is another great preventative measure.
If you’re still struggling with no hot water coming out of the tap, don’t wait—let Maintracts Services solve the problem for you. Call us today on 020 8131 6267 or book an appointment online.
Oliver Osmore has been part of Maintracts Services since 2001, following in his father’s footsteps. As Managing Director, he ensures the company runs smoothly, supports customers and engineers, and thrives on solving complex problems others can’t. Highly organised and approachable, Oliver works closely with customers to deliver tailored solutions, drawing on his extensive experience in plumbing, heating, and electrical services to resolve enquiries efficiently.
Since 1974, Maintracts Services has built a reputation for high-quality installation, maintenance, and repairs. Under Oliver’s leadership, the company remains committed to professionalism, safety, and customer satisfaction.
FAQ
Why Is There No Hot Water Coming Out Of My Tap, But The Cold Water Is Running Fine?
This issue could be caused by boiler problems, incorrect boiler pressure, a broken mixer valve, or blockages in the pipes. Start by checking your boiler’s pressure, ensuring it’s between 1-2 bar, and inspect the mixer tap for clogs or damage.
My Boiler Seems Fine, But I Still Have No Hot Water. What Should I Do?
If the boiler is functioning properly, the problem may lie in the plumbing system. Check for leaks, frozen pipes (in winter), or airlocks. You can also inspect the tap aerator or mixer valve for blockages and clean them if needed.
What Does It Mean If My Boiler Pressure Is Too Low?
Low pressure (below 1 bar) prevents the boiler from detecting water flow, which means it won’t activate to heat water. You can top up the pressure using the filling loop on your boiler, but it’s best to investigate the root cause, such as leaks or blockages.
Can I Fix A Broken Mixer Valve Myself?
Yes, minor issues like debris or limescale build-up can be fixed by cleaning the valve or replacing the internal cartridge. However, if the valve is severely damaged, it’s best to call a professional to repair or replace it.
