Small pressure changes as a heating system warms and cools can be normal. What is not normal is having to continually restore the pressure because the gauge repeatedly falls below the boiler's normal operating range.
Why Does Boiler Pressure Keep Dropping?
Possible causes include:
- A visible leak from a radiator, valve or pipe
- A small hidden heating-system leak
- A leak within the boiler
- Expansion-vessel problems
- Pressure-relief valve issues
- Air being released after recent heating-system work
Check for Visible Leaks
Without removing any boiler covers, look around accessible radiator valves, exposed pipework and underneath the boiler for signs of moisture.
If you can see water coming from the appliance, read our boiler leaking water guide.
Pressure Drops Only When the Heating Cools
Pressure naturally varies as system water changes temperature, but a large or progressively worsening change can suggest an expansion-related problem.
If pressure rises excessively while heating and then falls very low after cooling, professional diagnosis is advisable.
See also boiler pressure too high.
Should I Keep Repressurising the Boiler?
If your manufacturer's instructions explain how to restore low pressure and you are comfortable following them, occasional repressurisation after maintenance may be appropriate.
If pressure repeatedly falls, however, continuing to top it up can hide the symptom without correcting its cause.
See our guide to low boiler pressure.
Can a Boiler Work With Low Pressure?
Some boilers will continue operating for a time, while others will display a fault or lock out when pressure falls outside their permitted operating range.
Always follow the instructions for your specific boiler rather than relying on a universal pressure figure.
Boiler Keeps Losing Pressure in South Ockendon?
Boilers 4 Essex can investigate whether the pressure loss originates in the boiler or the wider heating system.
Call 07720 928585 or book a boiler repair in South Ockendon.
Frequently Asked Questions
Why do I have to keep topping up my boiler?
Repeated topping up usually means the system is losing pressure for a reason and should be investigated rather than continually repressurised.
Can a radiator leak cause boiler pressure to fall?
Yes. A leak anywhere in a sealed central-heating circuit can contribute to pressure loss.
Can Boilers 4 Essex find a pressure problem?
Yes. Our South Ockendon boiler repair service diagnoses boiler and heating-system pressure faults.
