Vaillant Aqua Sensor How to test and fix the easy way

All combies have a sensor or switch to start the boiler when a hot tap is turned ON, this is the Vaillant way. The video shows you how to test correctly. Our boiler FAULT Codes book is now an app. If you install service or a breakdown engineer this app is for you. Phone or email support from the app. Our “Special Offer” is order both books, order value £40.00 include. P&P no vat UK Post Code only. Order the books & CO2 chart from https://www.mrcombi.com/shop/ Our APPs are all one price £4.99 no vat Apple iOS download: https://apps.apple.com/gb/developer/m... Google Play download: https://play.google.com/store/search?... BOOKS: https://www.mrcombi.com/shop/