Heating Not Working? What to Check First
Before you assume the worst, a few quick checks solve more heating problems than you'd expect.
Heating or hot water that's stopped working is stressful, especially in cold weather. Before calling anyone out, these checks take a few minutes and solve a surprising number of common faults.
1. Check the Pressure Gauge
Most heating systems have a pressure gauge on the front of the unit that should sit somewhere around 1 to 1.5 bar when the system is cold (check your system's manual for the exact figure, as it varies by model). If the pressure has dropped too low, the system may refuse to fire. Many systems have a simple filling loop to top the pressure back up — if you're comfortable doing this and your manual explains how, it's worth trying before calling anyone out.
2. Check the Thermostat and Timer Settings
It sounds obvious, but a thermostat set too low, a programmer stuck on the wrong schedule, or batteries dying in a wireless thermostat account for more "heating breakdowns" than people expect. Double-check the settings and swap the batteries if you're unsure.
3. Check the System Has Power
Look for a tripped switch on your consumer unit (fuse box), and make sure the heating unit's own isolation switch — often a fused spur nearby — hasn't been knocked off. A unit with no power will show no lights or display at all.
4. Look for a Frozen Condensate Pipe
This is a very common winter fault. Most modern heating units have a white plastic condensate pipe running outside the property, and in freezing weather it can ice up and block, causing the system to cut out and show a fault code. If you can see the pipe and it's accessible, gently pouring warm (not boiling) water over the frozen section can thaw it — never use boiling water, as it can crack the pipe.
5. Check for a Fault Code or Warning Light
Most modern heating units display a fault code on a small screen when something's wrong. It's worth noting this down (or taking a photo) even if you don't know what it means — it'll help whoever comes out to look at it diagnose the problem faster.
6. Older System? Check the Pilot Light
If you have an older heating unit without electronic ignition, check whether the pilot light has gone out. Many have simple relighting instructions printed on a panel inside the casing — follow them carefully, and if it won't stay lit after a couple of attempts, stop and call a professional rather than repeating it indefinitely.
Never open up or attempt to repair the internal, gas-carrying parts of a gas appliance yourself — this is genuinely dangerous and illegal to work on without Gas Safe qualifications. That applies to AVEC too: we repair the heating and hot water system around the appliance, and we’ll tell you honestly when a fault needs a Gas Safe registered engineer instead. If you smell gas or suspect a leak, leave the property and call the National Gas Emergency Service on 0800 111 999 immediately.
If you've been through these checks and you still have no heating or hot water, it's time to get a second pair of eyes on it. AVEC Plumbing Services covers heating and hot water fault-finding — pumps, valves, radiators, cylinders and controls — across Crawley and the surrounding area.
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