Boiler installation - flushing

I believe so, but I'm no plumber.

If the old one's still in circuit, there is no mystery.

If not, boiler pipes can be short circuited for pumping.

NT

snipped-for-privacy@gmail.com brought next idea :

I agree, really stupid to flush after a new install - that will flush into the new boiler.

This is a well-known firm, that says they are part-owned by WB, and they will forward confirmation from WB that the procedure they have used is okay. So far, they haven't.

Are they fitting a magnetic filter to keep crud out of the new boiler ?. They should and might be relying on this to collect the rust particles.

Andrew pretended :

Noiler manufacturers seem to insist on one, for the warranty. They do only collect the rust particles - no use at all for collecting other debris, which can still obstruct a modern boilers water passages. So basically - if it needs flushing, it needs to be flushed before a new boiler is fitted.

Some have a cyclonic filtration action as well for non magnetic stuff - however their ability to "hang onto" the non magnetic crud is presumably more limited.

There are 3 filter modes used by these things in varying combinations

1. magnet
2. filter mesh
3. cyclone

I'd hate to rely on any of them to filter everything out.

NT

Do good plumbers fit service valves to all the pipes at the boiler?

(Mine didn't.)

Owain

You can't do that. Close them all and there would be nowhere for water to expand to.

Except perhaps the expansion(sic) tank.

Modern boilers have them built into the inlets.

Is there still a requirement to have two, if connected to potable water?