Generally speaking there are two different types of lead acid battery, Starting and Deep Cycle. If a starting battery is routinely deep cycled (discharged below 20%-50% of max capacity) it will generally fail after 30-150 cycles. The same starting battery will last for thousands of cycles if it is just used normally (2% - 5% discharge).
These phosphates precipitate the solids to the bottom of the boiler drum. At the bottom of the boiler drum there is a bottom blow to remove these solids. These chemicals also include anti-scaling agents, oxygen scavengers, and anti-foaming agents.
Boiler types: which boiler is best for your home. Whatever type of boiler you're thinking of buying or if you just want to find out more about the one you have, our boiler guide will help. When choosing which boiler is best for your home, you first need to choose which type. There are three main types of boiler: combi, system and conventional. Combination boilers - more commonly known as combi boilers - are the most popular kind in the UK and provide heat and hot water with no need for water tanks or cylinders.