What the manufacturers ask for
Most boiler manufacturers require the system to be cleaned and treated to BS 7593, the British Standard for treating water in heating systems, before a new boiler is fitted. If it is not, and the boiler fails because of sludge or scale, the warranty claim can be refused. Your installer should be able to tell you what cleaning is included in the price and show it on the paperwork.
Why it matters more on a new boiler
Modern boilers have narrow heat exchangers and are far less tolerant of debris than the one being replaced. Sludge that an old boiler shrugged off for years can block a new one in months. It is the most common reason a new boiler fails early, and the one the manufacturer will not pay for.
A cleanse and a powerflush are not the same thing
"Cleaned to BS 7593" can be met by a basic chemical cleanse: dose the system, circulate it on the pump, drain down. That ticks the box on the warranty form. It does not move the sludge sitting in the bottom of your radiators, which is where it has settled for a decade.
A powerflush puts a high-flow pump across the system and clears every radiator individually at velocity until the water runs clear. It takes most of a day, and it is the only version where every radiator is tested with a thermometer afterwards.
Having a boiler fitted by someone else? You can still book us for the flush beforehand. Many installers are happy with that, and some ask for it.
Two things to ask your installer
- What cleaning is included, and is it a chemical cleanse or a powerflush?
- Will the system be dosed with inhibitor to BS 7593, and is that on the paperwork?
Recent replacements
Every one went in onto a system we had cleaned first. More on the homepage.
Not sure the boiler needs replacing?
Ask us first. A boiler check will tell you straight whether it is worth saving, and a good flush fixes more "dying boilers" than people expect. If it does need replacing, we supply and fit it onto a properly cleaned system, so the warranty stands from day one.
