Heating Not Working But Hot Water Is? Eastbourne Fixes

You wake up in Eastbourne, the house feels cold, the radiators are lifeless, but the shower is piping hot. That usually sends people straight to the boiler in a mild panic.

The good news is that heating not working but hot water is points to a fairly recognisable set of faults in UK systems. It doesn't always mean a major breakdown. Quite often, the problem sits in the controls, the system pressure, a radiator valve, or a boiler part that switches between hot water and heating.

A sensible diagnosis starts by splitting the problem in two. Is it the whole house with no heating at all, or is it just one radiator, one floor, or one heating zone staying cold? That distinction saves time and often saves money as well.

That Cold Morning Feeling When Hot Water Works But Heating Doesnt

This is one of the most common winter complaints in local homes. A family in Meads or a landlord in Polegate will often describe the same thing. Taps are fine, the boiler sounds alive, but the radiators never get going.

In most UK homes, especially those with a combi boiler, that pattern makes sense. The boiler can still produce domestic hot water even when something is stopping central heating from circulating properly. That's why the house can feel like an icebox while the kitchen tap is perfectly normal.

First reassurance: if hot water is working, the boiler isn't necessarily dead. The fault is often narrower than people fear.

Older Eastbourne properties add another layer. Some have mixed heating upgrades over the years. You might have a newer combi boiler paired with older radiators, sticky TRVs, ageing wiring centres, or zoning that doesn't behave consistently. In flats and converted homes, I also see confusion caused by smart controls and schedules being accidentally overridden.

The mistake many homeowners make is treating every version of this fault as the same. It isn't. A full heating failure usually points you toward controls, pressure, pump, or an internal boiler fault. One cold room, one floor, or one stubborn radiator points you toward TRVs, air, sludge, balancing, or a zone valve problem.

That's the route a calm engineer takes. Start with the simple checks you can do safely. Stop before you get into gas, electrics, or boiler internals. If the fault sits beyond the obvious, get a Gas Safe engineer involved before a small issue turns into a larger repair.

Your First Five Checks Thermostat Timers and Boiler Pressure

Before anyone starts worrying about pumps, valves, or boiler parts, check the controls. In my experience around Eastbourne, a fair number of "no heating" calls turn out to be a setting, a schedule, or low system pressure rather than a serious breakdown.

Make sure the controls are calling for heat

Hot water and heating are often controlled separately. That matters, especially in homes with programmers, smart thermostats, motorised valves, or upstairs and downstairs zones. If the hot water side is working, do not assume the heating side is being asked to run.

Work through these checks in order:

1. Check the programmer or controller mode. If it is set to hot water only, the boiler can still produce hot water while the radiators stay cold.

2. Turn the room thermostat up well above room temperature. That removes any doubt about whether it is asking for heat.

3. Check smart thermostat schedules and overrides. Holiday mode, manual off periods, and app changes can block heating without it being obvious at the thermostat itself.

4. Replace thermostat batteries if it has them. Low batteries can cause poor communication or no call for heat at all.

5. Listen for a click or response. You may hear the thermostat, wiring centre, zone valve, or boiler react when heating is selected.

This is also the point where the whole-house versus single-zone question becomes useful. If every radiator is cold, the fault is more likely to be with controls, pressure, circulation, or an internal boiler issue. If only one zone is cold, such as downstairs heating off but upstairs working, the problem often sits with a zone valve, separate thermostat, or that part of the system's controls.

Pimlico Plumbers also notes that simple checks like confirming the programmer settings and checking boiler pressure are sensible first steps in a hot-water-but-no-heating fault, particularly on combi systems, in their hot water but no heating guide.

Read the pressure gauge properly

If you have a combi boiler, look for the pressure gauge on the front panel or underneath the appliance. Low pressure is a common reason heating drops out while hot water still seems normal.

For many sealed systems, the gauge usually wants to sit around 1 to 1.5 bar when cold. If it has fallen much below that, the boiler may refuse to heat properly or may lock out on heating demand first.

Low pressure is a symptom as much as a fault. Topping it up may bring the heating back, but it does not explain why the pressure fell in the first place.

If the pressure has dropped once after bleeding a radiator, that can be straightforward. If it keeps falling, treat that as a separate fault and get it checked properly. This guide to what causes a boiler to lose pressure explains the common reasons and when a simple top-up stops being a safe long-term answer.

Two checks homeowners often miss

Sometimes the control side is fine, but the system still is not sending heat where you expect it.

• TRVs turned down in multiple rooms. If thermostatic radiator valves have been shut or left very low, it can look like the heating is not working when the issue is local to the radiators or one area of the house.

• Heating not reselected after a reset or power cut. I see this more than you might think. The boiler comes back on, hot water works, and everyone assumes the heating should follow, but the controller is no longer set the way it was before.

Do the checks above safely and carefully. If the boiler needs panels removed, if there is a fault code you do not understand, or if you suspect wiring, stop there and get an engineer in.

Troubleshooting Individual Radiators and Cold Zones

If the boiler is getting a call for heat, the next question is simple. Is everything cold, or is the problem limited to one radiator, one room, or one part of the house?

That matters because the fix is very different.

One radiator cold usually means a local problem

A single cold radiator, or one that's warm at the bottom but cold at the top, usually points to air trapped inside. Bleeding it is the first sensible step.

A radiator that stays cold even after bleeding often has a valve issue. On many systems, the numbered head on the side is a TRV, short for thermostatic radiator valve. These can stick shut, especially after summer when they haven't moved for months.

Try these checks:

• Bleed the radiator carefully. Hold a cloth under the bleed point and release air until water appears steadily.

• Check the TRV setting. Make sure it hasn't been turned right down.

• Test for a stuck pin. If you remove the TRV head, the small pin underneath should move freely. If it's stuck down, the radiator may never open.

• Feel the pipework. One hot pipe and one cold one can tell you a lot about whether water is reaching the radiator.

If you want the exact safe method, this complete homeowner guide to bleeding radiators is a good place to start.

One floor or one zone cold points to controls

This is the part many generic guides miss. If downstairs heats but upstairs doesn't, or the lounge warms up while the extension stays freezing, don't jump straight to “the boiler is broken”.

Many UK homes use zone controls, TRVs, and motorised valves. Government-backed energy advice continues to emphasise controls such as programmable room thermostats, TRVs, and zone controls, and that's one reason zone-specific faults matter so much in real homes. Consumer guidance also highlights that failed motorised zone valves or stuck TRVs can leave one room or floor cold while hot water still works, as noted in HomeServe's advice on hot water but no heating.

When only part of the house is cold, the boiler may be doing exactly what it's told. The weak point is often the control for that zone.

In Eastbourne, I see this a lot in larger houses that have had extensions, loft conversions, or heating upgrades over time. A newer smart thermostat might be controlling one area, while an older motorised valve serves another. If the wiring centre, thermostat pairing, or valve head fails, one part of the property goes cold and the rest behaves normally.

A quick way to separate the fault

Symptom	Most likely area to check
All radiators cold	Controls, pressure, boiler fault, pump
One radiator cold	Air, TRV, lockshield, sludge
One floor cold	Zone valve, thermostat, wiring centre
Some radiators heat, others don't	Sludge, air, balancing, valves

If the fault is clearly localised, stay focused there. Don't let anyone sell you a boiler repair before the system controls and radiator valves have been ruled out.

A Deeper Look Inside the Boiler Diverter Valve and Pump

If every radiator in the house is cold, but the taps still run hot, the fault often sits inside the boiler rather than out at the radiators. That is the point where I stop looking at TRVs and room-by-room controls and start thinking about two internal jobs. Switching the heat to the right circuit, and circulating it properly once it gets there.

In a combi boiler, the diverter valve directs heated water either to your hot taps or to the heating circuit. If that valve sticks in the hot water position, the boiler can still make plenty of domestic hot water while the radiators get little or nothing. That fault pattern is much more common on whole-house heating failures than on single-room problems.

Here's a simple visual of what that part is doing inside the appliance.

Why a diverter valve causes this exact fault

A stuck diverter valve can give a very specific set of symptoms. You call for heating, the boiler sounds as if it is trying to work, but the radiators stay cold throughout the property. In some cases, radiators may get slightly warm only when a hot tap is running, which points to poor internal switching rather than a problem with one zone valve or one radiator.

That distinction matters. If one floor is cold and the rest of the house heats normally, I would still be looking outside the boiler first. If the whole house is cold, hot water is fine, and the boiler pressure and controls have already been checked, the diverter valve moves much higher up the list.

The pump is just as important.

Its job is to move heated water around the heating circuit. If the pump is seized, weak, or not being told to run, the boiler may fire but the heat stays near the appliance instead of reaching the radiators. A homeowner sometimes notices hot pipes close to the boiler and cold pipes further away. That is a useful clue, but it is not proof on its own because other faults can produce a similar pattern.

Common signs that point toward a pump or internal circulation fault include:

• All radiators staying cold or barely warm

• Boiler firing, but little heat leaving the boiler area

• Heating working only intermittently

• Boiler responding differently on hot water than on heating

In Eastbourne, I also see boilers where age, wear, and debris inside the system start to affect moving parts. Sometimes that means a repair is possible. Sometimes the part is worn enough that replacement makes more sense. The right call depends on the boiler model, condition, and cost of labour versus parts.

If you are not sure whether you have a combi or another setup, this essential guide to combi boiler systems in Eastbourne explains the differences clearly.

A short visual explanation can make the sequence clearer.

https://www.youtube.com/watch?v=fAAYZ3XNZgE

Boiler internals are the point where DIY should stop. Removing the case, forcing a stuck part, or testing live components is not safe for a homeowner. If you notice burning smells, unusual electrical buzzing, or anything that makes you suspect a gas issue rather than a heating-only fault, read this homeowner guide on gas leak detection and act on the safety steps first.

Knowing When to Call a Gas Safe Engineer

There's a clear line between homeowner checks and professional work. You can safely inspect settings, look at pressure, bleed a radiator, and make sure valves are open. Once the fault points toward boiler internals, wiring, gas, or electrical testing, that line has been reached.

Stop and book an engineer if you notice these signs

• Fault codes you don't understand. Resetting blindly can waste time and hide the pattern the engineer needs to see.

• Boiler case needs removing. That's not homeowner territory.

• Burning smells, scorch marks, or buzzing electrics. Switch off and get help.

• Repeated pressure loss. A top-up isn't a repair.

• No response from zone valves or controls after basic checks.

• Suspected pump or diverter valve issue. These need proper testing.

If you smell gas at any point, don't start fault-finding on the heating. Follow gas emergency steps first. A practical homeowner guide on gas leak detection is worth reading so you know the warning signs and the immediate actions to take.

Sometimes the heating isn't broken in the strict sense

One issue homeowners often describe as “the heating not working” is poor heat delivery. The boiler runs, but the house warms slowly, one room lags behind, or the cost of running the system feels too high to justify using it.

UK homeowner guidance points out that while energy efficiency has improved in many homes, older housing stock often has inefficient heating systems, and sometimes the problem is slow heat-up or high running cost rather than a straightforward mechanical failure, which is why a professional efficiency assessment can be worthwhile, as discussed in Glow-worm's advice on boilers giving hot water but no heating.

That's common in older Eastbourne homes with dated controls, tired pumps, sludge in the radiators, or pipework that was altered over the years. In those cases, chasing a single “broken part” can miss the actual issue.

Common Heating Repairs and Estimates

I won't invent figures where they vary heavily by make, model, access, and fault. The honest answer is that cost and time depend on diagnosis first.

Fault	Typical Repair	Estimated Cost (UK)	Estimated Time
Low system pressure	Repressurising and checking for underlying cause	Varies by cause	Usually short if no leak is present
Air in radiator	Bleeding radiators	Often minimal if straightforward	Usually short
Stuck TRV	Freeing or replacing valve parts	Varies by valve and condition	Usually short to moderate
Failed motorised zone valve	Valve head or valve replacement	Varies by system layout	Moderate
Pump fault	Pump testing, repair, or replacement	Varies by boiler and system	Moderate
Diverter valve issue	Internal boiler repair	Varies by boiler model	Moderate
Sludge or poor circulation	System cleaning or power flush	Varies by system condition	Longer job

For homeowners who want a qualified diagnosis without guessing, Harrlie Plumbing and Heating handles boiler and heating fault finding in Eastbourne and nearby areas. The useful part of that service isn't just repairing parts. It's narrowing the issue properly so you don't replace the wrong component.

Good heating repairs start with a sharp diagnosis. Swapping parts because the symptom sounds familiar is how simple jobs become expensive ones.

Get Your Heating Fixed Fast in Eastbourne

When your heating stops but your hot water still runs, the right move is a calm one. Check the controls. Check the pressure. Work out whether the problem affects the whole house or only one radiator or zone. That small bit of logic cuts through a lot of confusion.

If the fault sits with a stuck TRV, trapped air, or an obvious setting issue, you may be able to sort it quickly. If it points to a zone valve, pump, diverter valve, wiring fault, or ongoing circulation problem, it's time to hand it over.

That matters even more in Eastbourne's mix of older terraces, seaside flats, and updated family homes, where heating systems often carry a bit of history. Additions, control upgrades, ageing radiators, and older pipe runs can all complicate what first looks like a simple boiler fault. Keeping the whole property in good order helps too, and broader essential roofing and building upkeep can make a real difference to how warm a home feels and how hard the heating system has to work.

For homeowners and landlords around Eastbourne, Bexhill, Hastings, and nearby areas, getting a proper diagnosis early usually costs less than repeated resets and guesswork. Warmth comes back faster, and the repair is far more likely to stick.

---

If your heating's not working but the hot water is, book a proper fault diagnosis with Harrlie Plumbing and Heating. A Gas Safe engineer can identify whether you're dealing with controls, circulation, a zone fault, or an internal boiler issue, then advise on the safest repair.