I have a vented fully pumped central heating system with a Potterton Suprima regular boiler all installed 15 years ago. The property is a small 2 storey 3 bed semi with 7 radiators and a cylinder. I have 2 leaking pump valves that I would like to replace preferably using the Drayton easy drain kit. The pump is located vertically next to the cylinder in a cabinet on the first floor. I guess the FE tank is about a metre above in the loft. I have tested that the bungs fit in the feed and expansion pipes and was wondering if anyone had any advice/suggestions before I commence the job. One specific query is if I should set the 3 position divertor valve to manual while this work is carried out? Also should I use a bit of jointing compound around the pipes before adding the new compression fitting valves? Many thanks for any help as I am very interested in the central heating systems/plumbing but have little practical experience.