Improve gas central heating control. On an open-vented system, if the pilot flame is lit but you don’t have any heat or hot water, you may find the ball valve is stuck in the feed and expansion tank. Regular service of your boiler saves you money every month on your heating costs and gives you peace of mind by ensuring safe operation. Really impressed with the efforts made by the company very clear pricing and excellent professional knowledge.”. The jury is still out on boiler.