Noticing your boiler pressure dropping during a heating cycle can be frustrating, and it’s often a sign something isn’t quite right. Whether you’re in Hornchurch, Romford or Dagenham, understanding why your system keeps losing pressure mid-cycle can help you act before it becomes a bigger issue.
What Causes Boiler Pressure to Drop While Heating?
Boiler pressure should remain relatively stable as your central heating warms up. If you find that pressure drops during use, especially mid-heat cycle, it could point to several underlying problems that need attention.
A likely cause is a leak somewhere in the system. It could be a visible drip from a radiator valve or an invisible leak under flooring or behind walls. Even a small leak can cause pressure loss over time, and when the system is working harder to heat your home, the drop becomes more noticeable.
Another common issue is a failing expansion vessel. This part of your boiler absorbs the pressure increase as water heats and expands. If it’s faulty or has lost its internal air charge, the pressure can fluctuate dramatically during heating cycles and fall below safe levels.
Lastly, a bleed of air trapped in the system or a faulty pressure relief valve can also trigger pressure drops, especially if they’re discharging water during operation.
Signs Your Pressure Drop Needs Attention
- Heating shuts off unexpectedly before reaching the target temperature
- You constantly need to top up your boiler’s pressure
- You hear hissing, dripping or see water under the boiler or radiators
- The pressure gauge drops below 1 bar during heating
If you’re experiencing any of these, it’s best not to ignore them. A boiler that repeatedly loses pressure may become less efficient, more expensive to run, or even unsafe.
What Should You Do?
Check your boiler’s manual to see what pressure range is normal, typically between 1 and 2 bars when cold. If the pressure consistently falls during operation, avoid continuously topping it up. Doing so can mask a leak and cause internal corrosion over time.
Instead, call a Gas Safe registered engineer who can test the expansion vessel, check for hidden leaks, and make any necessary repairs to stop the pressure loss for good.
Based in Hornchurch, Romford or Dagenham and Dealing With Boiler Pressure Drops?
RDS Plumbing Ltd offers reliable boiler diagnostics and repairs across Hornchurch, Romford and Dagenham. If your pressure keeps dropping mid-cycle, we’ll find the cause and fix it quickly. Call us on 08000282031 or 01708444685, or use our contact form to book a visit.
