On Wed, 19 Dec 2012 13:56:56 +0000, fred wrote:

It's the cogs that have worn out so it's a complete replacement. One of
my reasons for being not being a fan Honeywell's enforced proportional
thermostatic control with multiple cycles per hour, it's wearing out my
controls prematurely.

Danfoss kit has the abilty to turn the valve knakering proportional
control off, in fact the instructsions tell you that doing so is
adviseable on systems with zone valves.

--
Cheers
Dave.