HCC80 and boiler modulation

[Gandi]

I wonder if I'm the only person seeing this potential issue...

I'm a long term and very happy Evohome user with mostly HR80 and HR92 radiator controls but with a couple of underfloor zones controlled by a first-gen HCC80. This has been working fine for several years.

A few months back I replaced my old oil boiler with a modulating (oil) Sapphire with the Opentherm interface. I initially added only the radiators and was very glad to see the Opentherm bridge (in the Evohome Summary Settings screen) frequently showing the boiler modulating down to lower percentages - something I'd not seen before with my old on/off boiler triggered from a BDR91.

I then added back in the HCC80 but quickly noticed modulation seems to have gone. Underfloor works fine but I only now see 100% on the display - never a lower rate and the boiler seems to cycle frequently as a result. Thinking I must have done something wrong, I removed, again factory reset and re-bound the HCC80 - but this has made no difference.

Is this normal? I'd have thought if anything called for 'long and low' heat this would be underfloor heating?

If I knew this was a failing with the HCC80 that was resolved in the newer HCC100, I'd buy that, but it seems a pricey leap of faith!

Thanks for any help you can give me.

[Richard]

What model evohome Controller do you have (look under the evotouch fascia)? If it is an ATC928G3000 is it on the latest 2024 firmware?

[Gandi]

Hi Richard. Yes, it's an ATC928G3000.

It's running 02.01.01.01 application software and 02.00.20.00. Wi-Fi software. I think these are latest versions?