{"product_id":"worcester-greenstar-junior-25si-and-30si-expansion-vessel-87161055450-87161064310","title":"WORCESTER GREENSTAR JUNIOR 25Si \u0026 30Si EXPANSION VESSEL 87161055450 87161064310","description":"\u003ch1 data-pm-slice=\"1 1 []\"\u003e\u003cspan\u003eWorcester Greenstar Junior 25Si \u0026amp; 30Si Expansion Vessel \u0026amp; PRV 87161055450 87161064310\u003c\/span\u003e\u003c\/h1\u003e\n\u003ch2\u003e\u003cspan\u003eProduct Overview\u003c\/span\u003e\u003c\/h2\u003e\n\u003cp\u003e\u003cspan\u003eThe \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003eWorcester Greenstar Expansion Vessel and Pressure Relief Valve Kit\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e is a replacement assembly designed for use in selected Worcester Bosch Greenstar heating systems.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eThe kit includes the \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003e6-litre expansion vessel (Part Number: 87161055450)\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e and the \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003epressure relief valve (Part Number: 87161064310)\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eThe expansion vessel accommodates the increase in water volume that occurs as the heating system warms up. Its internal diaphragm separates the system water from a pressurised air or gas chamber, helping to maintain stable system pressure during normal operation.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eThe pressure relief valve provides an additional safety function by releasing excess system pressure when it reaches the valve's specified operating limit.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eThis kit provides the two components required for applicable replacement and servicing work on compatible Worcester Greenstar appliances.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eℹ️ \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003eProduct Condition Options:\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eThis part may be available in \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003eNew or Refurbished\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e condition. Please check the available options from the dropdown menu.\u003c\/span\u003e\u003c\/p\u003e\n\u003ch2\u003e\u003cspan\u003eTechnical Insight \u0026amp; Common Failure Symptoms\u003c\/span\u003e\u003c\/h2\u003e\n\u003cp\u003e\u003cspan\u003eThe expansion vessel helps control pressure changes within a sealed central heating system by accommodating the expansion of water as it heats up.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eOver time, the vessel's internal diaphragm can deteriorate or the air pre-charge can be lost. The pressure relief valve can also become worn or fail to seal correctly.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eTypical symptoms associated with a faulty expansion vessel or pressure relief valve include:\u003c\/span\u003e\u003c\/p\u003e\n\u003cul data-spread=\"false\"\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eBoiler pressure repeatedly increasing when the heating system is operating\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eHeating system pressure rising excessively as the water heats up\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003ePressure dropping after the heating system cools down\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eWater discharging from the pressure relief valve outlet\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eFrequent need to repressurise the heating system\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eExpansion vessel losing its air or gas pre-charge\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003ePressure relief valve failing to close or seal correctly\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eBoiler shutting down due to abnormal system pressure\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cspan\u003eReplacing the faulty expansion vessel and\/or pressure relief valve with the correct components may help restore stable system pressure and reliable operation.\u003c\/span\u003e\u003c\/p\u003e\n\u003ch2\u003e\u003cspan\u003eTechnical Specifications\u003c\/span\u003e\u003c\/h2\u003e\n\u003cul data-spread=\"false\"\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003ePart Type:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Expansion Vessel \u0026amp; Pressure Relief Valve Kit\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eExpansion Vessel Part Number (MPN):\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e 87161055450\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003ePressure Relief Valve Part Number:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e 87161064310\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eExpansion Vessel Capacity:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e 6 Litres\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eVessel Type:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Diaphragm Expansion Vessel\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eApplication:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Sealed central heating systems\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eBoiler Range:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Selected Worcester Greenstar appliances\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003e\u003cspan\u003eCompatibility\u003c\/span\u003e\u003c\/h2\u003e\n\u003cp\u003e\u003cspan\u003eThis kit is designed for selected models within the \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003eWorcester Bosch Greenstar\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e range, including:\u003c\/span\u003e\u003c\/p\u003e\n\u003cul data-spread=\"false\"\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eGreenstar 25Si\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eGreenstar 25Si LPG\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eGreenstar 30Si\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eGreenstar 30Si LPG\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eSelected Greenstar i System appliances\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eSelected Greenstar i Junior appliances\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cspan\u003eThe expansion vessel reference \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003e87161055450\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e is listed for the Greenstar 25Si and 30Si models, as well as other selected Greenstar i System and Junior appliances. The associated pressure relief valve reference \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003e87161064310\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e is identified as a Worcester Bosch PRV. Compatibility of the complete kit should be checked against the individual appliance parts diagram.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003ePlease strictly verify the manufacturer part numbers \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003e87161055450\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e and \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003e87161064310\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e against your boiler's technical manual, exploded parts diagram, or existing components before ordering to guarantee correct fitment.\u003c\/span\u003e\u003c\/p\u003e\n\u003ch2\u003e\u003cspan\u003eSafety Advice\u003c\/span\u003e\u003c\/h2\u003e\n\u003cp\u003e\u003cem\u003eThe expansion vessel and pressure relief valve form part of the boiler's sealed hydraulic and pressure safety system.\u003c\/em\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cem\u003eInstallation, replacement and servicing should only be carried out by a \u003cstrong\u003esuitably qualified heating engineer\u003c\/strong\u003e in accordance with the manufacturer's instructions and applicable UK safety regulations.\u003c\/em\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cem\u003eBefore carrying out any work, ensure the boiler and heating system are safely isolated and that the system has been brought to the appropriate pressure and temperature conditions.\u003c\/em\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cem\u003eNever obstruct, cap or disable the pressure relief valve discharge. Always check that the replacement components have the correct specifications for the appliance.\u003c\/em\u003e\u003c\/p\u003e","brand":"Worcester","offers":[{"title":"Unknown","offer_id":44535558635623,"sku":"N8647","price":64.99,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0615\/0923\/8887\/files\/N8647.jpg?v=1787654057","url":"https:\/\/nationalboilerspares.co.uk\/products\/worcester-greenstar-junior-25si-and-30si-expansion-vessel-87161055450-87161064310","provider":"National Boiler Spares","version":"1.0","type":"link"}