A recent install is this Thermal Earth ASHP linked to a Jupiter UFH system and a few radiators. The radiator circuit is connected via a plate heat exchanger to keep the systems separate in terms of water mixing.

I recently participated in a round table discussion with other Viessman Boiler installers about the advantages and benefits of using Viessman boilers. 

An annual service is a check that the boiler is working safely. This is very important on older boilers, as they don't have as many safety features as modern, high-efficiency boilers. However, all boilers need to be checked to ensure that they are operating safely....