Clean out a combi boiler system??

sid1234_2

I had new radiators installed in the whole property about 4-5 years ago but want the system to be as clean as possible before my new boiler change. I don't really have the money for a powerflush so ive been told about using sentinel x800 in the system.


the rough advice ive been given is:-


with system cold....


isolate the boiler
open drain valve
after pressure has stopped, open towel radiator bleed valve
let water drain out then close drain valve+ bleed valve
pour sentinel x800 into other valve on towel radiator
turn boiler on and top up system pressure


run system like this for a week then my installer will drain out the system and refill with fresh water ready for the boiler change


does this sound correct or have I missed anything?

lewishardwick

You'll need to go around and bleed all the radiators.

sid1234_2

after the system is turned back??

southcoastrgi

I would use X400 if you aren't powerflushing, X800 doesn't need to be in for a week & needs completely clearing out of your system

Zandoni

A lot of engineers will not fit a boiler without a power flush, It may be worth checking with the manufacturer.

southcoastrgi

It doesn't need to be powerflushed but it does need to be flushed

sid1234_2

Thanks very much for the help...

Will the x400 be ok if left in for a week? Will that one treatment be enough or should I do it a couple of times before the engineer visits?

southcoastrgi

This time of year when your heating is on a week will be fine for X400, once is fine but the most important thing is the flushing out & the system will need to be filled & emptied a couple of times, manual flushing is very labour intensive & you will be saving money if you flush it yourself, the best thing if you can is to remove the rads & flush them with a hosepipe outside

sid1234_2

Thanks very much for your help south coastrgi

I will stick the x400 in and then drain and refill the system a couple
Of times the day before the engineer arrives.

Unfortunately I won't be able to remove the rads and flush them manually due to time constraints.