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Once the HW supply temperature falls to the mixed flow temperature then the UFH pump will be supplied only from here, it will pump it through the UFH...

The boiler's pump will almost certainly be running anyway because that will have an over run on it. But an UFH pump will normally just pump round the...

Thanks, understood, but the TMV will demand full flow from the boiler circuit and none from the UFH recirc due to the mixed temperature reduction so...

Evohome will use a 90C flow temp on 100% heat demand, whether that demand is from HW or CH. Hence why I say it doesn't differentiate between HW and...

With UFH, what you want is that the UFH pump stays on for as long as possible during the entire heating schedule. But what a BDR91 will try and do is...

Is this how it works?. During the off cycles, the boiler circ pump & the UFH manifold pump are running (with the UFH zone valve open).

My UFH has its own motorised zone valve. So the BDR91 was connected to the zone valve. The microswitch inside the zone valve would power the pump....

Thanks for the reply, I have not really noticed this tbh. What timer would you recommend and did you connect direct to the pump or to the BDR91? ...

I have a Main and have an X plan. Evohome does differentiate between HW & CH. When my Opentherm requests HW reheat, it demands an 80oc flow temp....

Now get ready to get frustrated with the BDR91 and its inbuilt TPI. It will keep switching the UFH pump on and off several times an hour, which is...

My guess is based on the Vaillant but it will be similar. The Intergas Cylinder NTC will tell the boiler what the temperature of the water in the...

On the Intergas x-plan wiring diagram, there is a cylinder ntc sensor. Does anyone know what part this plays when there is also a cylinder sensor...

No need to reply, figured it out thanks to the Evohome Shop YouTube on how to wire a BDR91, it appears the electrician did not put the link wire...

Nope,another missed opportunity, even though the OTB is able to distinguish between CH and HW workloads, it doesn't do much with it. Except when...

So the TPI issue is probably sufficient to send me down the x-plan route. Out of interest, does the evohome opentherm implementation allow different...

I absolutely hate that TPI is built into the firmware of the BDR91. It should have been overrideable. Worse still the relay settings available in the...

Doesn't work well with Opentherm. I ended up changing my NC Motorised valve to a NO one as per the old system before the Firmware update. The...

Not that I can think of, the software now just gives existing installations the option. What we fought for though was the forced DHWP setting that...

Thanks. I guess that was what I was trying to determine. To make sure I have this correct. DHWP is a new feature in the latest firmware. Before that...

The Evohome now allows you to implement DHWP regardless of the way the system is piped. You could always implement DHWP with an X plan with a...

Is that true with x-plan? I thought in that case the CH loop opened when the DHW loop was closed. ie just one BDR91 on the DHW loop.

Being the guy who coded all this into Domoticz, I have some bad news. Evohome uses none of this information! Infact in the latest firmware, it didn't...

In order to use HW priority, you will need BDR91 controlling the HW and CH loops, in addition to your OTB that fires the boiler.

I just changed it as soon as the boiler had been installed. I dropped it down to around 12kW first. No change to efficiency and then dropped it the...

Having just had an Intergas boiler installed, with an OpenTherm bridge, I'm impressed with the amount of additional information that has appeared in...

Thanks again. That's something that I'll have to remember to revisit when the weather gets colder. My installer mentioned that the power required for...

I tried the flow at 60c but it was taking too long for a room to warm. 65c was better but still a time lag, noticeable on colder days. I settled on...