Boiler installation - flushing

[GB]

I have a well-known firm installing a WB boiler today, to replace our old boiler.

They say that their normal way of doing things is to connect up the new boiler, add chemicals, and flush the system for an hour. Then drain and refill.

This seems all wrong to me, and indeed the WB installation manual says: "A new appliance must only be used to assist the cleaning of a newly installed system."

Surely, they should have flushed the system with the old boiler, or do a power flush?

Any suggestions about what to do?

[tabbypurr]

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

[Harry Bloomfield, Esq.]

[e-mail] brought next idea :

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

[GB]

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.

[Andrew]

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.

[Harry Bloomfield, Esq.]

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.

[John Rumm]

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.

+1 or at least, it can be fitted, but isolated at its service valves.

[tabbypurr]

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

[spuorgelgoog]

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

(Mine didn't.)

Owain

[Dave Plowman (News]

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

[Roger Hayter]

Except perhaps the expansion(sic) tank.

[John Rumm]

Modern boilers have them built into the inlets.

[Dave Plowman (News]

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