In message , Doctor Drivel
writes

A good pump should last 10 years minium if fitted properly. Cheap
pumps dop't last.

Huh! These are Grundfoss and far from cheap.

Sounds like they are not fitted right.

Hmm.. This is a fairly big system; 21 radiators all fitted with TRV's
except two on bypass. The pump becomes noisy as the system reaches
temperature, particularly on overrun and hence the change to the
adaptive type.


By fitting one now, or converting the existing cylinder which is a
cheap way, you instantly get a state-of-the-art system and bang up to
date. The benefits are immense. Do not underestimate the buffer
effect for CH, of a heat bank. A Dunsley is not cheap and does
little. The DHW was taken off via an immersed coil. Look at the
Navitron web site and forum. They have many there who use solar
panels and solid fuel with heat banks.
http://www.navitron.org.uk/forum/index.php

They are pretty negative about wood burning boilers:-(

Type the words, heat bank, into the search and lots comes up.

OK. At some future stage we may want to let the main farmhouse so I
am anxious to keep the heating system understandable.

What is not understandable about a heat bank?

Pass.

regards


--
Tim Lamb