The Spirax Sarco LRV2 liquid pressure reducing valve is supplied with one of three colour coded spring ranges:
Grey 0.35 - 1.7 bar g
Green 1.40 - 4.0 bar g
Orange 3.50 - 8.6 bar g
This information is located on the adjustment knob coloured insert (Q).
Check that the LRV2 has the correct spring range for your application.