Four Types of Sludge
Rust is the common term for a series of Iron Oxides
1. Black Sludge. This is the most familiar and can be found in most heating systems over five years old. It will affect the performance of radiators and the hot water efficiency.

2. Limescale Pellets with Oxidised Copper, Rust and Aluminium.
No, this is not gravel!! If you find this in your header tank you have a serious problem which will manifest itself in boiler noise and a serious loss of efficiency. This will occur where the hot system water is pumping over into the supply tank and constantly refreshing itself, thereby manufacturing a constant supply of limescale

3. Brown Sludge.
This is ‘Fresh Sludge’ – on it’s journey to becoming black sludge. Your system is making air and new rust!!

4. Flakes of Red Rust!!
This is new rust: but most common in radiators fitted since the millenium and even more common when installed alongside plastic piping. If your pipework is 10mm it can block ‘solid’ when allowed to ‘rest’ over a summer period.

5. Sheet scale
We removed this from a large copper heat exchanger: it’s easy to see why scale increases energy consumption with an extra 10mm between the flame and the waterway!
Other favourites we remove are chipboard from makeshift tank lids, glass fibre loft insulation and hair-felt pipe wrapping.
