Services

Areas

Advice

About

Contact

07712 646488

WhatsApp us

Services

Areas

Advice

About

Contact

WhatsApp us

BOILER FAULTS

No hot water,
or no heating?

Which one of the two you have lost is the most useful diagnostic there is. It usually points at the part before anyone opens the boiler.

5.0from 213 Google reviews

Gas Safe registeredEvery engineer on the job

Approved InstallerExtended manufacturer warranties

Get your hot water back

THE SHORT ANSWER

Heating fine but no hot water usually means the diverter valve. Hot water fine but no heating usually means the pump or a motorised valve. Neither working usually means pressure, ignition or the PCB.

On a combi the same boiler does both jobs, so losing only one of them tells you the fault is in the part that chooses between them rather than in the boiler itself. That is why the first question we ask on the phone is not what make it is, it is which of the two you have still got. Get that right and you have narrowed a callout down to a handful of parts before anyone gets in the van.

NARROWING IT DOWN

What you can check, and what it points at.

Five minutes with this list saves you paying somebody to tell you the thermostat batteries were flat.

Check these first

Two minutes, no tools

Pressure gauge

Should read 1 to 1.5 bar cold

Fault code

Photograph it before resetting

Room thermostat

Batteries in, set above room temperature

Timer or programmer

Not reverted after a power cut

Other gas appliances

Do they light

Condensate pipe

In cold weather, is it frozen

What each points at

Before anyone opens anything

Heating only

Diverter valve, usually stuck

Hot water only

Pump, motorised valve or controls

Neither, low pressure

Leak, relief valve or expansion vessel

Neither, code showing

Ignition, fan, flue or PCB

Neither, cold snap

Frozen condensate, most likely

Intermittent

Hardest to find. Note times and codes

THE THREE PATTERNS

What each pattern usually means.

Heating works, no hot water

Most often the diverter valve, the part that sends hot water either to the taps or to the radiators. They stick, usually in the heating position, which is why the radiators carry on working. It is a common and generally straightforward repair on most combis.

Hot water works, no heating

Usually the pump, a motorised valve, or the room thermostat rather than the boiler. Before calling anyone, check the thermostat has battery and is calling for heat, and check the timer has not reverted after a power cut, because both happen more than you would think.

Neither works

Start with the pressure gauge and any fault code. Low pressure and a frozen condensate in winter cover a large share of these. If pressure is fine and there is a code on the display, photograph it and call, because that is the boiler telling you exactly where to look.

WHAT TO EXPECT

What is likely, and what it means for you.

Heating fine, no hot water

Usually the diverter valve.

A common combi fault and generally a straightforward repair on a boiler that is not too old. It is the part that decides whether hot water goes to the taps or the radiators, and it tends to stick in the heating position.

Hot water fine, no heating

Often not the boiler at all.

Pump, motorised valve, or the controls. Before booking anyone, put fresh batteries in the room thermostat and turn it well up. It is a surprisingly common cause and it costs you nothing to rule out.

Neither, and the pressure is low

Top it up once, then watch it.

Bring it to about 1.5 bar cold on the filling loop and see whether it holds. If you are doing that every week, the problem is not the pressure, it is where the water is going.

Neither, and there is a code

Photograph it and call.

The code is the most useful thing you have. It often tells us the part to bring, which turns two visits into one. Send it with the make and model when you message.

COMMON QUESTIONS

Questions we get asked.

Why do I have heating but no hot water?

Why do I have hot water but no heating?

My boiler has no hot water and no heating. What should I check?

Is a diverter valve worth repairing?

How quickly can you come out?

Will you tell me what it costs before you come?

Lost your hot water or your heating?

Tell us which one you have lost and the make of the boiler. That usually gets us to the likely fault before we set off, and you get the price first.

BOILER SERVICING

GAS SAFETY (CP12)

HEATING & PLUMBING

LANDLORD PACKAGES

GOT A PLUMBING OR HEATING JOB IN BRIDGEND?

Get your hot water back

BEFORE YOU GO

Keep reading.

More of the same, written by the engineers who do the work.

READ THIS FIRST

What a new boiler actually costs

Real fitted prices, what pushes them up, and the three lines to check in any quote.

Read it

→

OTHER SERVICES

New boiler installation

→

Boiler servicing

→

Boiler repair

→

Gas engineer

→

WORTH A READ

Worcester vs Baxi vs Vaillant vs Ideal

→

How to reset a boiler

→

Cold radiators explained

→

Boiler losing pressure

→

No hot water,or no heating?

No hot water,or no heating?

No hot water,or no heating?

Heating fine but no hot water usually means the diverter valve. Hot water fine but no heating usually means the pump or a motorised valve. Neither working usually means pressure, ignition or the PCB.

Heating fine but no hot water usually means the diverter valve. Hot water fine but no heating usually means the pump or a motorised valve. Neither working usually means pressure, ignition or the PCB.

Heating fine but no hot water usually means the diverter valve. Hot water fine but no heating usually means the pump or a motorised valve. Neither working usually means pressure, ignition or the PCB.

What you can check, and what it points at.

What you can check, and what it points at.

What you can check, and what it points at.

Check these first

Check these first

What each points at

What each points at

What each pattern usually means.

What each pattern usually means.

What each pattern usually means.

Heating works, no hot water

Heating works, no hot water

Hot water works, no heating

Hot water works, no heating

Neither works

Neither works

What is likely, and what it means for you.

What is likely, and what it means for you.

What is likely, and what it means for you.

Usually the diverter valve.

Usually the diverter valve.

Usually the diverter valve.

Often not the boiler at all.

Often not the boiler at all.

Often not the boiler at all.

Top it up once, then watch it.

Top it up once, then watch it.

Top it up once, then watch it.

Photograph it and call.

Photograph it and call.

Photograph it and call.

Questions we get asked.

Questions we get asked.

Questions we get asked.

Why do I have heating but no hot water?

Why do I have hot water but no heating?

My boiler has no hot water and no heating. What should I check?

Is a diverter valve worth repairing?

How quickly can you come out?

Will you tell me what it costs before you come?

Lost your hot water or your heating?

Keep reading.

Keep reading.

Keep reading.

What a new boiler actually costs

What a new boiler actually costs

What a new boiler actually costs

OTHER SERVICES

WORTH A READ

No hot water,
or no heating?

No hot water,
or no heating?

No hot water,
or no heating?