I have read a fair bit on mains 'powered' flushing here, and wanted to say thanks to folks - all very useful. I am in the middle of replacing a 30 year old cast-iron boiler for a new condensing one, and aiming to move to a sealed system at the same time, so I wanted to note one other useful part. It allows you to pressure test the pipework up to at least the static mains pressure (3.1 bar in my case) at the same time.
I flushed first of course, in case there was a leak - stops gunky water going on carpets etc. I also went up 1 bar at a time, and left it for 15 mins each time to see if there was an invisible leak. All seems solid which is good news - I have a feel that the system was bodged in 30 years ago (e.g. vent pipe did not rise from the boiler to the roof tank - it went down a metre, across 6, up a story, back another 6, then up!, and there was joined to another vent for the water circuit somewhere along the way), so I was a little nervous.
Another benefit for a DIY job is that it can be done slowly - I know that this isn't useful for tradesmen, but since I have multiple circuits to trace and split, it's good to be able to be flushing one circuit whilst tracing another. Oh, before anyone wades in, I do know about Part L (and P and M), the sense of having a CORGI technician handle the gas side, and the need for building reg approval - all in hand.
Cheers
Greg
I flushed first of course, in case there was a leak - stops gunky water going on carpets etc. I also went up 1 bar at a time, and left it for 15 mins each time to see if there was an invisible leak. All seems solid which is good news - I have a feel that the system was bodged in 30 years ago (e.g. vent pipe did not rise from the boiler to the roof tank - it went down a metre, across 6, up a story, back another 6, then up!, and there was joined to another vent for the water circuit somewhere along the way), so I was a little nervous.
Another benefit for a DIY job is that it can be done slowly - I know that this isn't useful for tradesmen, but since I have multiple circuits to trace and split, it's good to be able to be flushing one circuit whilst tracing another. Oh, before anyone wades in, I do know about Part L (and P and M), the sense of having a CORGI technician handle the gas side, and the need for building reg approval - all in hand.
Cheers
Greg
