Water leaking from or around your boiler should never be ignored — it can damage your home, cause electrical faults, and lead to dangerous corrosion inside the appliance. Our Gas Safe registered engineers across Cardiff find and fix boiler leaks quickly, isolating the source on the same visit wherever possible. Boiler leaks have several typical causes: a faulty pressure relief valve (PRV) discharging because system pressure is too high, corroded internal pipework or fittings, a failed pump seal, a cracked heat exchanger, or a perished rubber seal on the pump or auto air vent. The location of the drip tells us a great deal — water from the bottom of the casing, from a copper pipe joint, or from the outside discharge pipe each points to a different fault. We never simply mop up and leave; we trace the leak to its source so the repair lasts. Where a heat exchanger has failed on an older boiler, we give honest advice on repair versus replacement so you can make an informed decision. Every visit begins with a fixed-price diagnostic from £85 with no call-out fee.
We isolate the water and, where appropriate, the electrical supply to the boiler to stop further leakage and protect your property before investigating.
We trace the leak precisely — distinguishing between a faulty pressure relief valve, a pump seal, corroded pipework, a heat exchanger crack, or a loose fitting.
We confirm the fault and quote a fixed price before starting. Common repairs — replacing the PRV, pump seal, auto air vent, or a corroded section of pipe — are completed on the first visit.
We refill and re-pressurise the system, run the boiler, and check for any further leaks before confirming the repair is complete and the appliance is operating safely.
Boiler leak diagnostics start from £85 fixed price with no call-out fee. Many leaks — a failed pressure relief valve, a pump seal, or a loose fitting — are repaired within the diagnostic visit. Heat exchanger failures and major internal corrosion are more involved; in these cases we give a clear fixed quote and honest repair-versus-replacement advice before any work proceeds.
A leaking boiler should be treated as urgent. Water near electrical components can cause short circuits, and ongoing leaks corrode internal parts and can affect safe operation. Switch the boiler off, isolate the water supply if you can, and call a Gas Safe engineer. Do not attempt internal repairs yourself.
That is usually the pressure relief valve (PRV) discharge pipe. It releases water when system pressure climbs too high, which often points to a faulty PRV or a failed expansion vessel. Our engineers diagnose and repair the underlying cause rather than just the symptom.
Most leaks — valves, seals, fittings, and pipework — are straightforward repairs. A cracked heat exchanger on an older boiler can be costly, so we give honest advice comparing the repair cost against a replacement so you can decide what makes sense for your home.
We aim to attend boiler leaks the same day, 24/7, across Cardiff and the surrounding areas. The sooner a leak is isolated and repaired, the less damage it causes to your boiler and your home.