On 22/09/2017 22:35, Roger Mills wrote:
On 22/09/2017 16:53, John Rumm wrote:
On 22/09/2017 10:33, Andrew Gabriel wrote:
In article ,
swoopdave m writes:
replying to Ed Sirett, swoopdave wrote:
What keeps the 3 way valve open to the rads while its over running?

Why does it matter which way it's open during overrunning?

If its open to the DHW, and that is already satisfied, you won't dump
much additional heat from the primary circuit into the cylinder - and
will lose more out of the flue than you would expect if overruning
through the rads.




And if it dumps it to the CH, and all the rads have TRVs which are
closed, it won't have anywhere at all to go.

Wouldn't that have been happening before the boiler turned off?