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45 years of trusted expertiseControl Valves & Diaphragms
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Restore peak boiler performance with our comprehensive range of replacement control valves and diaphragms. We stock genuine manufacturer-approved components designed to ensure accurate pressure regulation and reliable water flow within domestic heating systems.
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Heating engineers know that failing control valves or perished diaphragms are common culprits behind pressure loss, poor heating circulation, and domestic hot water fluctuations. Our extensive selection of genuine boiler spares covers everything from pressure relief valves and diverter components to specific rubber diaphragms for major boiler brands. Sourcing the correct manufacturer-approved parts ensures that safety tolerances are met and prevents premature wear in the water section of the boiler. Rubber diaphragms often degrade over time due to constant expansion and contraction, while control valves can seize from limescale build-up in hard water areas. Replacing these integral components with exact matches guarantees a watertight seal and restores the correct hydraulic function of the system. Whether you are conducting an emergency winter callout or carrying out a routine service, you can secure the necessary spares quickly through our network of over 350 branches, with many items ready for free Click & Collect in just five minutes.
Frequently Asked Questions
How do I know if a boiler diaphragm has failed?
A degraded or split boiler diaphragm usually presents as a failure to trigger the domestic hot water microswitch. When a tap is turned on, the pressure differential should push the diaphragm forward to engage the switch and fire the boiler. If the rubber has perished or torn, the system will not register the demand for hot water, leaving the radiators functioning normally but the taps running cold.
Can I use a generic rubber diaphragm for my boiler repair?
It is strictly advised to use the manufacturer-specific diaphragm for your exact boiler model rather than a generic alternative. Boiler diaphragms are moulded to precise dimensions and flexibility tolerances required by the specific water section casing and pin assembly. Using an incorrect size or material thickness can lead to internal leaks, restricted pin movement, or a complete failure to engage the diverter valve.
Why is my boiler pressure relief valve continuously dripping?
A continuously dripping pressure relief valve typically indicates that the system pressure has exceeded the standard safety limit, often caused by a flattened expansion vessel or a passing filling loop. However, if the system pressure is reading normally and the valve still leaks, the internal seal of the control valve has likely been compromised by grit or scale. Once a valve seal is damaged in this way, the component will need to be replaced to maintain system integrity.