Nest and Opentherm

[panholio]

Hi,

I have posted this on a couple of forums... wondered if anyone on here might have an idea as I know a few of you understand smart heating controls.

So the issue is with my newly installed heating system and it is this:

[*]The system is a Intergas Eco RF 24 running as a heat only system boiler with a 3rd generation nest and a Joule unvented cylinder
[*]It is an S-Plan set up with two Honeywell zone valves, one for hot water one for heating
[*]Nest is connected to the boiler by the two OpenTherm wires and is mounted on the wall, powered by some other wires the installer re-used - so it is not on the USB plug adapter that comes with it
[*]The heating functions perfectly - when called the boiler fires up, the zone valves open and the radiators warm up. The flow temp can be adjusted by the nest, everything works as it should. Boiler modulates nicely and the nest holds the house and a steady temp really well
[*]The nest is set to OpenTherm for heating and "on/off" for hot water, and is set as a system boiler
[*]If hot water heating is called for the zone valve opens and the water tank is heated ONLY if the radiator heating is going.
[*]If there is no heating called for , and you just ask for water on its own, the zone valve opens but the boiler does not fire. My understanding is the boiler should fire at it's max flow temp when hot water is demanded until the target temp is reached.
[*]My Nest shows software version 5.6 1-4

Nest have made two visits (well not nest it is Help Link, and they are just not that well versed in Openther, connections). Installer has been back numerous times and we did add a switched live from the hot water zone valve to the boiler. This did make the boiler fire for hot water demand, but it sent it a bit crazy, cycling on and off every 90seconds or so. This has been removed.

I have three options now the way I see it....

Find some sort of fault with the set up and magically it all starts working
Send it back and go for something different. Debating Tado.
Abandon the whole OpenTherm thing and set it all up as just on/off


Any help anyone can provide would be massively appreciated. I'm at an absolute loss! Nest and intergas have been pretty useless.

[panholio]

Thanks for the reply.

This is what I feared - it just doesn't seem to work. I am wondering if I scrap it and go for tado - but again unsure if I will run into the same problems.

An installer over on another forum says he has got the exact same configuration as mine to work fine, just seems off the opentherm controls heating fine, but won't do hot water.

[panholio]

Hi, yes they are.