No Heating? 8 Safe Checks Before You Call
Before you book an engineer for a dead heating system, eight checks take ten minutes and resolve a meaningful share of no-heat calls outright. All of them are outside the boiler case: settings, supply, pressure, condensate and one reset. If they don't restore heat, you'll have gathered exactly the information that makes the engineer's visit faster — which is worth the ten minutes either way.
Checks 1–4: controls and supply
One — thermostat: is it set above the current room temperature? A stat at 15°C in a 17°C room is correctly doing nothing. Check batteries too; wireless stats fail silently and the boiler simply never hears a call for heat. Two — programmer or timer: is it in an 'on' period, and has the clock drifted (or missed a daylight-saving change) so the schedule fires at the wrong time? Holiday mode left engaged is a classic.
Three — gas supply: try a gas hob or another gas appliance. If nothing gas works, the fault is supply, not boiler — check the meter for error messages, prepayment credit, or an emergency control valve that's been turned. Four — electrical supply: is the boiler's fused spur or switch on, and has an RCD tripped in the consumer unit? A dead display is often just electrics.
Checks 5–8: pressure, condensate, code, reset
Five — pressure gauge: below 1 bar and most boilers lock out. Top up via the filling loop to 1.2–1.5 bar as our repressurising guide describes. Six — condensate pipe: in freezing weather, feel along the external white plastic pipe for ice and thaw it with warm water. In a cold snap these two checks alone account for a large share of winter no-heat calls.
Seven — read the error code and note it exactly; our brand code guides explain what the common ones mean and which have homeowner-safe first steps. Eight — press reset once, and let the boiler run a full ignition attempt. Once. Repeated resetting against a persistent fault isn't a fix; the lockout exists because the boiler has decided something is wrong.
When to stop and call
Stop immediately and call the National Gas Emergency line on 0800 111 999 if you smell gas — leave the property first, don't operate switches. Stop and book an engineer if: the code returns after one reset, pressure falls again within hours, the boiler fires then cuts out repeatedly, you hear banging or kettling, or you see water leaking from the boiler.
Also call rather than persist if the house contains young children, elderly or medically vulnerable residents and the weather is cold — say so when booking, since no-heat triage prioritises vulnerability. Nothing on the checklist above is worth an hour of stubbornness in a cold house.
Making the call count
Have five facts ready: boiler make and model (on the front or inside the door), the exact error code, whether other gas appliances work, the pressure gauge reading, and whether anything works partially (heating but no hot water, or vice versa). Those five sentences do more for a first-visit fix than any amount of description, because they let the engineer load the likely parts before setting off.
And mention what you've already tried — a household that has thawed the condensate, topped the pressure and reset once has genuinely eliminated the common causes, which tells the engineer to bring the diagnostic kit rather than the easy answers.
| # | Check | Fixes |
|---|---|---|
| 1 | Thermostat setting & batteries | No call for heat |
| 2 | Programmer schedule / holiday mode | Wrong or no timing |
| 3 | Gas supply (test the hob) | Supply or meter fault |
| 4 | Electrical supply / RCD | Dead boiler display |
| 5 | Pressure gauge — top up if low | Low-pressure lockout |
| 6 | Condensate pipe frozen? | Winter lockouts |
| 7 | Read and note the error code | Directs diagnosis |
| 8 | One reset | Clears transient faults |
Describing this fault when you call
Whatever you've concluded from the symptoms, describing observations rather than conclusions gets the better outcome: what the boiler display shows, what you hear during a start-up attempt, what the pressure gauge reads, whether other gas appliances work, and what you've already tried. That description lets an engineer arrive with the right parts and price the job accurately over the phone — which is most of what 'fixed first visit' actually consists of.
Frequently asked questions
How many times should I reset my boiler?
Once, after addressing a cause you can safely reach. Repeated resets against an unknown fault override a safety decision the boiler made deliberately — and delay the repair that's actually needed.
My boiler has power but won't fire — what's most likely?
In winter, a frozen condensate pipe or low pressure lead the list, followed by gas supply and ignition faults. The error code narrows it quickly — note it before calling.
Is no heating an emergency?
In cold weather, or with vulnerable residents in the house, yes — say so when booking. In mild weather with hot water still working, it's usually urgent rather than emergency, and a standard-rate next-day slot saves money.
What if the checks fix it but it fails again?
Recurrence is information: a lockout that returns points at an underlying fault the reset only masked. Book the visit and report what you did and how long it lasted — that pattern is genuinely diagnostic.
The honest next step
Where you go from here depends on what you've worked out. A boiler that's running but grumbling can wait for a standard appointment, which is cheaper and calmer for everyone. No heat in cold weather — especially with young children, elderly or medically vulnerable residents in the house — should be booked as urgent, and you should say so when you call, because that's how triage works. Either way, describing the symptoms in the terms this guide has given you gets the right engineer with the right parts first time.
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