Worcester Bosch Safety Relief Valve 3 Bar 87174010120

The Worcester Bosch safety relief valve is a 3 bar pressure relief component used on Greenstar and RD Series gas boilers. It sits in the closed heating circuit and opens proportionally once system pressure reaches its set rating, discharging water through the boiler's relief pipework to bring pressure back down. By venting that excess, it protects the appliance and the wider system from the damage caused by uncontrolled pressure build-up.

• Water continually dripping or running from the boiler's pressure relief discharge pipe when the system is cold
• Boiler pressure creeping up during heating and failing to settle back to its normal cold reading
• The valve weeping at the outlet even after the system has been repressurised to the correct level
• Scale, sludge or debris visible around the valve seat, stopping it from sealing fully
• System pressure dropping repeatedly because the valve is passing water and needs topping up

• Check the GC number and appliance serial plate against the compatibility list to confirm the correct valve for your model.
• Confirm the numbers on the existing valve match 87174010120 or one of the alternative numbers listed below before ordering.
• Inspect the valve seating and any sealing washer on removal, as a replacement seal may be needed to get a clean joint.
• This part is fitted to a gas appliance; installation must be carried out by a Gas Safe registered engineer.