What is the middle pipe for on the water valve? Customer Support February 23, 2021 15:42 This is where you connect the water to the steam generator. Please ensure you use only WRAS approved hoses or hard plumbing, never fabricate a pipe as this could fail under pressure. Related articles Steam generator letting hot water out of steam outlet. Where is the hot and cold feed connection? What is the AMI system? Can I use any essential oil in the system? How strong is the tray? Comments 0 comments Please sign in to leave a comment.