Intergas Eco RF and Nest problem

[paulj48]

Hi, had an Eco RF30 fitted last Tuesday, connected a Nest 3rd gen via OpenTherm. The Nest had previously been used on my old boiler as an on/off, I did a factory reset on the Nest and setup again.

I've set a maximum CH temp of 85c and lowest 30c on the boiler. The Nest is over heating by 2c on its initial **** (whilst I'm at work ready for when I come home at 5:30) The Nest is set at 20.5c

When I got home from work the temperature in the room was 23c and the boiler off, 2 hours later the temperature has dropped to 20c and fired up the boiler, by this time the CH water in the rads and pipe is stone cold, the boiler is heating to 85c. The boiler stays at this temperature for approx 15 minutes when the Nest shows 20.5c and switches off.

I was under the impression the Nest would only ask for very hot water if there was a large difference in the target and current temperature, in the case above should the Nest not have circulated cooler water for longer? Will this change over time once the Nest has learnt?

Also what is the number displayed on the panel when you hold in the 'plus' in CH mode?

cheers.