You’re strolling through your kitchen, kettle on for a proper brew, when you spot it – a sneaky puddle under your boiler. Cue the sinking feeling: Is your boiler about to call it quits? Will you be shivering through tomorrow’s shower?
As a Gas Safe Engineer who’s tamed countless boilers, I’m here to break down why your boiler’s leaking underneath and how to sort it.
Let’s get stuck in…
PS We fit new combi boilers with a gas safe installation nationwide. Simply answer these questions, get your fixed price, and you could get it installed as quickly as tomorrow.
Why Is My Boiler Leaking? The Usual Suspects
A leak under your boiler can feel like a plumbing horror story, but it’s often caused by something fairly straightforward. Here are the most common culprits:
#1 Pressure Problems
Boilers are a bit like Goldilocks – they like their pressure just right.
If the pressure is too high, your boiler might start leaking from the pressure relief valve (PRV) to let off steam (well, water).
If the pressure is too low, you might have a different issue, but high pressure is a frequent leak trigger.
How to Fix:
Check your boiler’s pressure gauge. For most combi boilers, it should sit between 1 and 1.5 bar when the system is cold.
If it’s creeping above 2.5 bar, you might need to bleed your radiators or call a Gas Safe engineer to inspect the PRV.
#2 Corroded Pipes or Fittings
Over time, the pipes and fittings under your boiler can corrode, especially if they’re exposed to moisture or haven’t been maintained.
A tiny pinhole in a copper pipe can cause a steady drip, and before you know it, you’ve got a puddle.
How to Fix:
This one’s a job for a professional. A Gas Safe engineer can replace corroded parts and ensure your system is watertight.
#3 Faulty Pump Seal
The pump in your boiler keeps water circulating through your system.
If the seal around the pump starts to wear out, it can leak, often leaving water pooling directly underneath.
How to Fix:
A new pump seal or, in some cases, a replacement pump might be needed. Again, this is engineer territory.
#4 Loose Joints or Connections
The pipework under your boiler is a bit like a jigsaw puzzle – everything needs to fit snugly. If a joint or connection is loose, water can escape.
This is especially common after a recent service or installation if something wasn’t tightened properly.
How to Fix:
A quick tighten might do the trick, but don’t go poking around yourself unless you’re qualified. Call in a pro to avoid making things worse.
#5 Condensate Pipe Issues
If you’ve got a condensing boiler (most modern ones are), it produces condensate – a mildly acidic liquid that’s drained away via a pipe.
If this pipe gets blocked or frozen (hello, British winter!), the condensate can back up and leak.
Watch our YouTube video guide on fixing a frozen condensate pipe below:
How to Fix:
Check if the condensate pipe (usually a white plastic pipe running outside) is blocked or frozen.
A gentle thaw with warm (not boiling) water can help, but if the problem persists, get an engineer to take a look.
Is a Leaking Boiler Dangerous?
A small leak might not seem like a big deal, but don’t ignore it. Left unchecked, even a tiny drip can lead to bigger problems like water damage, corrosion, or even boiler breakdowns. If you spot a leak, here’s what to do:
Turn off the water supply to the boiler to limit the leak.
Place a bucket or towel under the drip to protect your floor.
Call a Gas Safe engineer pronto. Don’t try to fix it yourself – boilers are complex beasts, and DIY repairs can be risky.
Oh, and if you smell gas or suspect a gas leak alongside the water, turn off the gas supply at the meter, open windows, and call the National Gas Emergency Service on 0800 111 999 immediately. Safety first, folks!
How to Prevent Boiler Leaks
An ounce of prevention is worth a pound of cure, as my nan used to say. Here’s how to keep your boiler leak-free:
Book an annual service: A Gas Safe engineer can spot potential issues before they turn into puddles.
Check the pressure regularly: Keep an eye on that gauge to avoid pressure-related leaks.
Insulate your condensate pipe: A bit of lagging can prevent freezing in winter.
Don’t skip maintenance: If your boiler’s making odd noises or acting up, get it checked sooner rather than later.
Do You Need A New Boiler?
In some cases, replacing a boiler can make more financial sense than continuing to repair it. Here are the key factors to consider:
Age of the Boiler - If your boiler has surpassed its average lifespan (typically beyond 15 years) and is no longer covered by the manufacturer’s warranty, replacing it may be a more cost-effective option to avoid recurring repair expenses.
Repair Costs - When the cost of repairing the boiler exceeds 50% of the price of a new one, it’s usually more financially sensible to invest in a replacement rather than continuing with costly repairs.
Frequency of Breakdowns - If your boiler is breaking down more frequently, it’s often a sign of significant wear and tear, and it is beyond economical repair. In such cases, replacing the boiler can help avoid mounting repair costs and the inconvenience of ongoing issues.
Energy Efficiency - Older boilers tend to be far less efficient than modern models, leading to higher running costs. Upgrading from a G-rated to an A-rated boiler could save you up to £385 per year in energy bills, making replacement a financially smart decision in the long run.
By carefully weighing these factors, you can determine whether replacing your boiler offers better value and peace of mind compared to continued repairs.
Need Help? Heatable’s Got Your Back
A leaking boiler is nobody’s idea of fun, but it’s usually fixable with the right know-how. If you’re staring at a puddle and wondering what to do next, don’t panic – just give us a shout.
At Heatable, we connect you with top-notch Gas Safe engineers who’ll have your boiler back in tip-top shape faster than you can say “cuppa”.
And if it’s time for a new boiler, our hassle-free online quoting tool makes it easy to compare and find the perfect model for your home.
Get A New Boiler Quote Today
If you’re aiming to get the best deal on a new boiler, consider getting your boiler installation with us. Here’s why:
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