On 23/10/2017 12:44, 100Packets wrote:
replying to Ed Sirett, 100Packets wrote:
COmbi boilers do not have diverter values. Hot water and radiator
systems are
completely separate

Some do, especially old ones, some have two pumps for water to either
flow to the radiators or the HW exchanger.

There is a heat exchanger so hot water is not mixed with primary circuit
water.

This might assist you with posting to a newsgroup, albeit through a website:
https://tools.ietf.org/html/rfc1855

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