Ideal Vogue Max, R8810A and Pump Speed

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  • Mr_Rodge
    Automated Home Lurker
    • Sep 2006
    • 2

    Ideal Vogue Max, R8810A and Pump Speed

    Hi,

    The other night I set up my R8810 and my Evohome thermostat with a load of HR92's. New to Evohome, goal is to eventually integrate with Home Assistant.

    All seems to work well, except my motivation for buying into Evohome was to get the most out of my shiny new Ideal Vogue Max 40 (I think it's massively oversized for my 4 bed 1 bath detached), which previously had an ESI on/off stat with the CH flow temp set to 65C at the boiler.

    Before installing Evohome I spent a few days getting the balancing as good as I could get it (I have a mix of old and new rads) and had a flow/return of 65/58C at the boiler plus a drop ranging from 1-8C at the rads (most were about 4C in the end, the 1 & 8 were the outliers that I couldn't get any better). Obviously I want to try and get the return temp lower than this for condensing.

    I have a fairly big radiator in the hall with no TRV and the lockshields fully open to act as a bypass. Looking at the install manual for my boiler, this is easily big enough to satisfy the 10% of minimum output. I wanted to have this as a zone with the Evotouch showing the temperature in the hall but no joy - the zone disappears as soon as I add my first TRV to another zone. Is there a way to display the temp?

    I noted that pump modulation was enabled on my boiler and I never saw it running any faster than 72% (minimum is 70%) before installing Evohome. Since I installed though the pump seems to run at a fixed 85%. This, combined with only the rads needing heat being on (as opposed to them all) appears to be causing a zero drop at the boiler (this morning was 57/57C). I can see the flow temp/burner is being modulated, which is a good thing (lowest flow temp I've seen set so far has been 27C, the boiler cycles the burner to achieve this but I'm not really bothered about that, it is what it is) so I should be condensing now but there's never any drop on return, suggesting the pump is too fast. Is there anything I can do about that? I don't know if it's a limitation of the boiler with OpenTherm or if it's the R8810 that's not asking for a slower pump speed but it seems needlessly fast.

    I've posted a similar post on the evohome shop forum and got a reply but I just got a sales pitch for an automatic bypass valve (apparently we're all wrong to use a radiator as a bypass, I just did this as the manual for my boiler said to do so) and some expensive automatic flow control rad valves - the reply didn't address the pump speed and when I responded I didn't get a further reply.

    Also I'm unable to register online for TCC - the form just throws an 'oops' error. Tried loads of devices, browsers and cookie settings but can't register an account for remote control! Any ideas?

    Thanks!
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