Can evohome drive a boiler with a 3-way mixing valve using the HM80?

[courcirc8]

Ah ah that is TPI! Very interesting!
(I initially though you wanted to explain what was a PID, but no, you was right to precise what it is, this is new to me) this document gave me more confidence about Evo energy efficiency but I have the impression Evo is unable to modulate the boiler's power, it seems to be 0 or full power while all recent boilers have different power available to improve efficiency in condensing mode.

Many thanks to all the contributor to this post.

By the way, you convinced me to abandon my mixing valve, and I'm looking to find an OpenTherm boiler. I started a new post to discuss the OT boiler/Evo good combinations and possibles issues:

http://www.wordpress-1219309-4387497.cloudwaysapps.com/vbulletin/showthread.php?4245-Compatibility-Evohome-Opentherm-with-different-boilers&highlight=opentherm

[courcirc8]

The boiler I'm currently targeting is the OERTLI OEnoviaFioul OVCR (18 or 24) with hot water tank 100HL which is apparently the same boiler as the Remeha Calora Tower Oil & Tank BS 100 HL.
This boiler has two output circuits:
-one direct circuit.
-the second one through a 3-way mixing valve.
Can you confirm that is is recommended to branch my installation on the direct circuit, in order to work in TPI mode?
Many thanks

[courcirc8]

Much better to have a truly weather compensated domestic boiler (for instance a Worcester Bosch Greenstar CDi with FW100 controls) with zoned heating demand from evohome - this is a great application with the best of both worlds (heating zone control where you need it and accurate boiler flow temperature control) and something I have done many times with excellent results.

I tried to let my weather regulation work on my current boiler (3 way mixing valve) but without communication with Evo It gives bad results: output temp are too low and zone regulation doesn't work, and when I change the regulation coefficient, output temp are at max...