Why Have I No Hot Water From My Boiler? Causes & Fixes
If you’ve been searching why have I no hot water, why isn’t my hot water tap working, or why is there no hot water to the shower, you’re probably dealing with a boiler fault that needs sorting quickly.
Maybe the heating is still working and the hot water isn’t. Maybe your hot tap runs cold. Maybe the shower has suddenly gone cold. Whatever the symptom, the cause is usually one of a handful of common issues with the boiler, controls, pressure, or a faulty component.
We’re Hinckley Plumbing & Heating, Gas Safe registered engineers working across Hinckley, Nuneaton, Leicester, Tamworth, Coventry, Rugby, and Loughborough, and this guide explains what to check, what the problem might be, and when to call us in.
Why Have I No Hot Water?
If you have no hot water from your boiler, the most common causes are low boiler pressure, a faulty diverter valve, timer or thermostat problems, a frozen condensate pipe, or an internal boiler fault.
If the heating still works but the hot water doesn’t, that often points to a specific hot water issue rather than a complete boiler failure. If neither heating nor hot water is working, the problem is more likely to involve power, gas supply, pressure, or a fault inside the boiler itself.
Why Isn’t My Hot Water Tap Working?
If you’re asking why isn’t my hot water tap working, the boiler may not be firing when the tap is turned on. That can happen if the pressure is too low, the controls aren’t set correctly, or a part inside the boiler is stopping hot water from being sent through.
If one hot tap is affected but others work, the issue could be local to that tap or pipework. If all hot taps are cold, the boiler or hot water system is the more likely cause.
Why Is There No Hot Water To The Shower?
If you’ve got no hot water to the shower but the taps are working, the cause may be the boiler, the shower valve, or the shower itself.
Mixer showers can fail because the thermostatic valve gets stuck or worn. Electric showers are different and may not be linked to the boiler at all. If the whole house has no hot water, though, the boiler should be checked first.
First Things To Check
Before calling someone out, there are a few simple checks worth doing.
- Check whether the boiler has power.
- Look at the pressure gauge.
- Make sure the timer and thermostat are set correctly.
- Check whether an error code is showing.
- See whether the boiler has recently been reset or had a power cut.
- In cold weather, check whether the condensate pipe might have frozen.
A surprising number of hot water problems come down to one of those basics.
Boiler Pressure Problems
Low boiler pressure is one of the most common reasons for no hot water.
Most boilers should sit around 1 to 1.5 bar when cold, although you should always check the manufacturer’s instructions for your model. If the pressure drops too low, the boiler may lock out and stop producing hot water.
If the pressure keeps falling, that usually means there’s an underlying issue such as a leak, a faulty valve, or a problem inside the heating system.
Timer, Thermostat, And Programmer Faults
Sometimes the boiler is fine, but the controls are stopping it from working properly.
A timer that’s set incorrectly, a thermostat turned down too low, or a programmer that has reset after a power cut can all stop hot water from coming through. This is especially common on systems with a hot water cylinder, where the cylinder thermostat or hot water schedule may have been changed without anyone noticing.
If the heating works but the hot water doesn’t, the controls are one of the first things to check.
Frozen Condensate Pipe
In very cold weather, a frozen condensate pipe can stop a boiler from working.
The condensate pipe carries waste water away from the boiler. If it freezes, the boiler may shut down as a safety measure and stop hot water production. This is more common when the pipe runs outside or through an unheated area.
If the boiler stopped working after a sudden cold snap, this is a likely cause.
Diverter Valve Problems
If the heating works but the hot water doesn’t, a faulty diverter valve could be the problem.
The diverter valve controls where heated water goes. When it fails, the boiler may still send heat to the radiators but not to the taps or shower. This is a common issue on combi boilers and usually needs an engineer to inspect or replace the part.
Gas, Power, Or Internal Faults
If the boiler has no power, no gas supply, or keeps showing an error code, the fault may be more serious.
Watch out for:
- Tripped electrics.
- Repeated lockouts.
- Banging, gurgling, or rattling noises.
- Leaks around the boiler or pipework.
- Hot water that comes and goes.
- A boiler that fires and then shuts down again.
If any of those are happening, it’s time to stop guessing and get it checked.
When To Reset The Boiler
A boiler reset can sometimes clear a temporary fault, but it should only be used after the basic checks have been done.
If the manufacturer says a reset is safe and the fault code points to a temporary issue, that’s fine. If the boiler locks out again straight away, don’t keep pressing reset. That normally means there’s a deeper fault that needs a proper diagnosis.
When To Call Us if You Have No Hot Water
Call Hinckley Plumbing & Heating if:
- You’ve checked the pressure, timer, thermostat, and power, and still have no hot water.
- Your hot water tap still isn’t working.
- There is no hot water to the shower.
- The boiler keeps losing pressure.
- The boiler is showing an error code.
- The hot water only works sometimes.
- The heating works but the hot water doesn’t.
- You can hear unusual noises from the boiler.
- There are signs of a leak.
- The boiler keeps switching itself off.
Those are all signs that the issue needs an engineer rather than another reset.
Book A Boiler Inspection
If you’ve been asking why have I no hot water, why isn’t my hot water tap working, or why is there no hot water to the shower, we can help.
We cover Hinckley, Nuneaton, Leicester, Tamworth, Coventry, Rugby, and Loughborough, and we’ll give you a clear, honest assessment of what’s wrong and what needs doing next. Whether it’s a quick fix, a faulty part, or a boiler that’s reached the end of its life, we’ll take a proper look and tell you straight.
Call Hinckley Plumbing & Heating or use our contact form to book a visit.
Why does my hot water go cold after a few minutes?
This can happen if there’s a fault with the boiler, a thermostat issue, low pressure, or a problem with the diverter valve. It can also point to a hot water cylinder problem on system or regular boiler setups.
Why is my boiler making a noise but not heating water?
A noisy boiler that isn’t producing hot water can suggest limescale build-up, trapped air, a failing pump, low pressure, or an internal component fault. If the noise is new or getting worse, it’s worth getting checked quickly.
Can I still use my heating if I have no hot water?
Sometimes yes, especially if the fault is limited to the hot water side of a combi or system boiler. But if the boiler is showing an error code, losing pressure, or shutting down completely, it may affect both heating and hot water.