No Hot Water but Heating Works in Basingstoke - What to Check First

Published October 2026 | Boiler Repair

Coming home to a cold shower when your radiators are putting out heat is one of those faults that can really knock you off balance, especially if you've never had a boiler problem before. It doesn't make obvious sense on the surface - if the boiler is working well enough to heat the house, why can't it heat the water? The good news is this is a well-understood fault that our engineers see regularly across Basingstoke, and there are some simple checks you can safely work through before picking up the phone.

What Is Actually Happening - The Basics Explained Simply

Your boiler has two separate jobs. The first is heating your radiators and towel rails - what engineers call the central heating circuit. The second is heating your domestic hot water, which is the water that comes out of your taps, your shower, and your bath. Even though both jobs are done by the same boiler, they use different components and different pathways to get heat where it's needed.

When your heating works but you're getting no hot water from the taps, it tells you something useful straight away: the boiler is firing up and generating heat just fine. The fault isn't with the burner or the ignition. Instead, something in the pathway between the boiler and your hot water supply has developed a problem. That narrows things down considerably.

The exact cause depends on what type of boiler system you have:

• Combi boilers - these are the most common type in modern UK homes. They heat water directly on demand, with no separate cylinder. When you open a hot tap, a component called a diverter valve switches the boiler's output from the heating circuit to the hot water circuit. According to the BOYLA team, a faulty or stuck diverter valve is one of the most frequent causes of this exact symptom in combi boiler households.
• System boilers and heat-only boilers - these work with a separate hot water cylinder, usually stored in an airing cupboard. In these setups, a motorised zone valve controls whether heat goes to the radiators or to the cylinder. A failing zone valve, a faulty cylinder thermostat, or a problem with the programmer can all leave you with heating but no hot water from the taps.

Knowing which type of boiler you have makes the conversation with your engineer much more productive. If you're not sure, look for a large hot water tank in your airing cupboard - if it's there, you have a system or heat-only setup. If there's no tank and the boiler sits alone on the wall, it's almost certainly a combi. Common makes you'll find in Hampshire homes include Bosch, Vaillant, Worcester, Ideal, and Baxi.

Is This an Emergency or Can It Wait?

For most households, no hot water is a serious inconvenience but not a safety emergency. The boiler isn't leaking gas, it isn't overheating, and you still have heat in the house. That said, there are situations where you should treat this as urgent:

• If you have young children, elderly relatives, or anyone with a medical condition that requires hot water, call an engineer today rather than waiting.
• If the boiler is making unusual noises alongside the hot water fault - banging, kettling, or a high-pitched whistle - get it looked at promptly. These sounds can point to a separate and more serious developing problem.
• If you notice any smell of gas at all, do not touch any switches or appliances. Leave the property immediately, leave the door open behind you, and call the National Gas Emergency Service on 0800 111 999.

For most people in Basingstoke dealing with this problem on a typical day, it's reasonable to run through some basic checks yourself first, then decide whether to book for later that same day or the following morning. If it's a weekend and you'd prefer to avoid out-of-hours call-out rates, waiting until Monday is usually fine - use the immersion heater or kettle in the meantime, and keep the heating running normally.

What You Can Safely Check Yourself (With Zero Experience)

These checks require no technical knowledge, and none of them involve opening the boiler or touching anything connected to the gas supply. Work through them in order before calling anyone out.

1. Check the boiler pressure gauge. Look at the front of the boiler for a pressure gauge - it usually shows either a dial with a needle or a digital reading. It should sit between 1 and 1.5 bar when the system is cold. If it's reading below 1 bar, low pressure may be affecting the hot water circuit. Most modern boilers can be repressurised using a filling loop - a small flexible pipe or integral valve underneath the unit. Your boiler manual will walk you through this step by step, and it's one of the few tasks you can safely carry out yourself.

2. Check your programmer and timer settings. Our engineers find incorrect programmer settings are behind more call-outs than you'd expect. Check that the hot water is set to "on" or "auto", not "off". Some programmers and smart thermostats have completely separate controls for heating and hot water, and the hot water setting can get accidentally changed - particularly after a power cut or when the clocks change.

3. Try a boiler reset. Find the reset button on your boiler - usually marked with a circular arrow symbol or the word "Reset" - and hold it for around three seconds. If the boiler fires up and hot water resumes, the fault may have been a one-off sensor trip or a temporary lockout. If it locks out again within a few minutes of running, there's an underlying fault that needs a professional.

4. Check the hot water temperature dial. On combi boilers, there's typically a separate temperature control for domestic hot water (usually marked with a tap icon) distinct from the heating control (marked with a radiator icon). Make sure the hot water dial isn't set to minimum - it can be knocked accidentally, particularly on older units.

5. Check for an immersion heater in the cylinder. If your home has a hot water cylinder in the airing cupboard, check whether there's an immersion heater fitted. It looks like a large electric element going into the side of the tank, with its own on/off switch on the wall nearby. Switching it on won't fix the boiler fault, but it will give you a hot water supply while you wait for an engineer to attend.

How to Find a Trustworthy Engineer in Basingstoke

The single most important rule when hiring anyone to work on your boiler: they must be Gas Safe registered. This isn't a recommendation - it's a legal requirement. Only a Gas Safe registered engineer is legally permitted to work on gas boilers in the UK. Always ask to see their Gas Safe ID card before work starts, and you can verify their registration number at the official Gas Safe Register website.

In Basingstoke and across Hampshire, there are plenty of heating engineers available, but quality and reliability do vary. Here's what to look for when making your decision:

• Gas Safe registration confirmed upfront - not just mentioned on a website, but verified before they start work.
• Clear pricing before the job begins - a reputable engineer will explain what they've found and give you a total cost for the repair before doing anything. Reluctance to commit to a figure upfront is a warning sign.
• Local customer reviews - look for engineers with reviews from customers in the Basingstoke or Hampshire area specifically. This confirms they're working locally and have a real track record in your area.
• Honest assessments - a good engineer will tell you plainly if a repair isn't the best option on an older boiler, rather than taking your money and leaving you in the same situation a few months later.

Voltrade's GoFIX diagnostic tool is worth running through before you book an engineer. It helps pinpoint the most likely cause of your fault based on your symptoms, so the engineer can arrive prepared with the right parts. That reduces the chance of a wasted visit and often means the repair gets done in a single call-out rather than two.

Avoid any engineer who can't give you a Gas Safe registration number upfront, who quotes a price over the phone without asking any questions about your boiler type or symptoms, or who pressures you into expensive work on the first visit without first explaining exactly what they've found.

What a Repair Visit Looks Like (So You Know What to Expect)

If this is your first time having a heating engineer come out, knowing what to expect removes a lot of the uncertainty. Here's how a typical visit for this kind of fault plays out from start to finish.

When they arrive: The engineer will ask you to describe what's happening - when it started, whether anything changed beforehand (a noise, a power cut, any recent work done in the house), and the make and model of your boiler. Having that information ready helps - you'll find the model on a label on the front of the unit.

Diagnosis: They'll run the boiler through its modes, testing both the heating circuit and the hot water circuit separately and checking temperatures and how quickly different parts of the system respond. As Gas Safe Solutions explain, engineers also carry out electrical tests to confirm whether sensors and valves are sending the correct signals. This process typically takes 20 to 40 minutes and is what allows the engineer to identify the exact fault rather than guessing.

The quote: Once the fault is identified, the engineer should explain it in plain terms and give you a total price for the repair - parts and labour combined - before doing anything. You're perfectly within your rights to ask for this in writing before you agree to proceed.

The repair: Most faults that cause this symptom can be resolved in a single visit. Replacing a diverter valve or a motorised zone valve typically takes one to two hours. If a part isn't available in the engineer's van, they'll order it and return - ask for a realistic timescale and confirm whether the return visit is included in the original quoted price.

After the work is done: The engineer should test both the heating and the hot water fully before leaving, and should explain what caused the fault and what to watch for going forward. Most reputable engineers offer at least a 12-month warranty on parts and labour for repair work.

Typical Costs - So You Are Not Caught Off Guard

Pricing for boiler repairs in Basingstoke is broadly in line with the wider South East. The ranges below are typical figures - actual costs will vary depending on your boiler make, the specific parts required, and the time the job takes.

• Call-out and diagnostic fee: typically 60 to 100 pounds. Many engineers apply this against the repair cost if you go ahead with the work, but confirm that before they arrive.
• Diverter valve replacement on a combi boiler: typically 150 to 350 pounds including parts and labour. This is the most common repair for the "heating works but no hot water" fault on combi systems.
• Motorised zone valve replacement: typically 150 to 250 pounds including parts and labour.
• Heat exchanger descale: typically 100 to 250 pounds, depending on the severity of limescale buildup. Basingstoke sits in a hard water area, which means limescale is a genuine contributing factor for local boilers over time - particularly on brands like Bosch, Worcester, and Ideal where heat exchangers are compact and more vulnerable to scaling.
• Cylinder thermostat replacement: typically 80 to 150 pounds.
• Power flush (if sludge or debris is restricting flow through the system): typically 300 to 600 pounds. This is usually carried out as a planned job rather than on an emergency visit.

If your boiler is more than 12 to 15 years old, the engineer may raise the question of whether repair is more cost-effective than replacement. That's a legitimate conversation worth having, but take your time with it. Ask for the recommendation in writing, compare it against the cost of the repair, and get a second opinion if you're uncertain. A good engineer won't push you into a decision on the day.

Questions You Should Ask Your Engineer

Having a few questions prepared before the engineer arrives makes the whole visit feel much less daunting, especially when it's your first time. These are the ones most worth asking:

1. "Are you Gas Safe registered and can I see your ID card?" - Ask this every time, without exception. A genuine professional won't take offence.
2. "What exactly have you found, and what does it mean in plain terms?" - You deserve a clear explanation without technical jargon.
3. "What is the total cost, parts and labour combined, before you start?" - Get a complete figure in writing before agreeing to anything.
4. "Is this repair likely to hold, or is there a wider problem I should know about?" - A trustworthy engineer will be direct with you about the boiler's overall condition.
5. "What can I do to prevent this happening again?" - Annual servicing is the standard answer, and it does make a real difference to catching faults before they develop.
6. "What warranty do you offer on the repair?" - 12 months on parts and labour is a reasonable expectation for most standard repairs.
7. "If you need to order parts, how long will that take, and is the return visit included in the quote?" - Worth confirming before you agree, to avoid surprise charges later.

First-Timer Questions

Why would my heating work but not my hot water?

The boiler is generating heat normally - the problem is with the components that direct heat toward your hot water supply. In combi boilers, the most common cause is a faulty diverter valve, which gets stuck in the heating position and can't switch over to serve the hot water circuit. As Homebuilding explains, this is one of the typical faults engineers investigate first for this symptom. In homes with a hot water cylinder, a failed motorised zone valve or a faulty cylinder thermostat produces the same result by blocking heat from reaching the stored water in the tank.

Is it safe to keep the heating on while I wait for an engineer?

Yes, in most cases it's completely fine to carry on using your central heating while you wait for a repair appointment. The heating circuit and the hot water circuit operate through separate components, even though they share the same boiler. Unless your boiler is displaying an error code you don't understand, making unusual noises, or you can smell gas, there's no safety reason to switch the heating off. That said, don't leave the fault unattended for weeks - problems can develop and become more expensive if ignored.

Could I have accidentally caused this by changing a setting?

It's more possible than people expect, and there's no reason to feel embarrassed about it. A programmer set to "off" for hot water, a temperature dial knocked to minimum, or a timer that reset after a power cut can all produce this exact symptom. Before calling anyone out, work through your controls carefully - both the physical dials on the boiler itself and any app-based smart thermostat settings. Our engineers in Basingstoke regularly attend jobs each year where the fix turns out to be correcting a setting rather than replacing any parts.

How long am I likely to be without hot water?

In Basingstoke, most engineers can attend within one to two business days for a non-emergency fault. Same-day attendance is often available, though it typically carries a higher call-out charge. If you have a cylinder with an immersion heater, switching that on gives you a temporary supply while you wait. Most repairs for this type of fault are completed in a single visit - typically one to two hours on site once the engineer has the right parts to hand.

What if the engineer says I need a new boiler rather than a repair?

If a replacement is recommended, ask for the reasoning in plain terms and ask what a repair would cost by comparison. On a boiler that's more than 12 to 15 years old, replacement can sometimes represent better long-term value - but you should never feel pressured into making that call during the visit itself. Take the written recommendation away, consider it properly, and if you're uncertain, get a second opinion from another Gas Safe registered engineer. Reputable engineers working across Hampshire don't push for a sale during a fault call-out.