In an earlier contribution to this discussion,
Jethro wrote:

Hi all

We have currently 8 rooms-size rads (in a bungalow) on our Vaillant
Turbomax combi.
SWMBO would like 2 extra rads ... a little one in the porch, and a
little chromey ladder one in the spare loo.
Am I right in thinking the boiler should be able to power two more
rads OK ?

How long is a piece of string? Your question is impossible to answer without
adding up the outputs of all your existing radiators, and comparing the
result with the boiler output to see how much spare capacity you have.

Having said that, if the boiler has been spec'd to give a good hot water
flow rate, it probably has more than enough capacity for the CH - but you
can't be absolutely sure without doing the sums.

As for fitting :

1) switch off boiler
2) drain CH
3) tap in, and fit plumbing
4) re-fill system. & bleed
5) check for leaks
6) ensure lockshields are tight
7) start up
8) bleed
9) check 2 new rads are getting as hot as the others by judicious
opening of the lockshield.
10) drain a bit
12) add inhibitor
13) go back to 4 and check again

That's basically it. Depending on the pipe layout, you may be able to
isolate the section where you're connecting your additional radiators
without draining the whole lot, and losing all the inhibitor.


(9) is an idiots understanding of CH balancing.

There's a bit more to it than that! Adding new rads will change the flow to
the existing rads to some extent, so you may have to adjust some these too
in order to get the balance right. Aim to get the same temperature drop
across all the rads.

--
Cheers,
Set Square
______
Please reply to newsgroup. Reply address is invalid.