Flanged rings RF
The Wilo-RF flanged rings are - apart from a few exceptions - intended for length compensation with PN 6 flanges (RF 4, RF 5 and RF 6 and also in PN 16). For length compensation with PN 10/16 flanges, a pipe modification is required.
RF7 (oval flange, hole circle D.80)
RF 8 (square flange, hole circle D.90)