Take it from me (Had Maxi Paws) and was disgusted with them. Same problem, Failed to trip the return, even on the sensitive setting. Took them all out, Ebayed them and replaced with RB 5000 Plus gear drives, AWESOME head, nice rain curtain tech, SAM filters if needed, and the MPR nozzles are a must....I have had REALLY good luck at 30' (foot) spacing at about 43-50 psi. As a matter of fact, i'm expanding my system and adding three more zones composed of these rotor heads as we speak, (type). I'm sure MANY on this and other site will recommend these heads.