Rocket Expansion valve OPV 1/8 Female  $21.31

Details:

This is an expansion valve or OPV with a 1/8'' female fitting

If it starts leaking into the water tank or drain then replace it - as you will be losing pressure during extraction and draining the boiler - causing unnecessary temperature fluctuations.

Easy to install - but you may have to add PTFE tape if there is a leak on the OP valve. 
 

Technical specifications:

• Material: Brass CW510L (OT57) Low lead
• Size:1/8 female BSP x  7mm (Silicon hose outlet )
• Adjustable 10-14 bar