I’m doing up an old house that has an old Ravenheat combi boiler fitted. It’s probably about 20 years old and I’m replacing it with a new Baxi combi. Which I’ve already bought and is sitting there waiting to be fitted. Along with the new magnetic filter.

I don’t want the sludge from the old system clogging up my new boiler so I’m going to flush it first. But as we’re going to be removing all the radiators while the system is down (and as soon as the weather warms up a bit) so we can plaster and decorate behind them I’m planning to flush them all out individually using a hose in the back yard when they’re off.

My question is, what order do I do things in. I initially thoght

1) Run a bottle of cleaner round the system.
2) Drain down, remove rads and hose them out
3) Fit new boiler and rads, fire up and go.

But then I thought it might be better (if more work) to do flush the rads first, then put them back on and run the cleaner round.

What would you do if it was your house?

Drain the system.
Flush the rads.
Fit the magnetic filter.
Put in sentinel 800 powerflush liquid.
Refill the system and run until the filter is relatively clean.
Drain the system and fit the new boiler.
Might be worth checking a few rads at this point to see if they are still clean.
Put the required inhibitor in.
If you do it this way round the system should be relatively clean and in the best condition for the new boiler.

Oh good. It’s the most time consuming method then. Thought it might be. 😥

What would you do if it was your house?

I’d probably get all the rads power flushed as my 30 year old system is full of crud, but being an old heat exchanger it’s perfectly happy pumping solder balls and old screws round the whole system….

Are you on a water meter? If not, hook up the mains to the feed pipe from the boiler and a hose from the return to the drains. Leave it running for hours and loads will come out. Then switch the pipes and do it again. And a dose of Sentinel too in the system for a day or two before you do this.

I can tell that Crofts2007 knows what he’s talking about but midlifecrashes – how about you? I’d like to take that advice but it’s remarkably close to the kind of thing I’d dream up!