The UFH is limited to a floor temperature of 27°C and is background heat, the water is recirculated around and around the system, and once it cools a bit more hot water is added, the motorised valves on the UFH look more like thermostatic radiator valves, they do not look the same as motorised valves used to switch between central heating and domestic hot water.
The whole control of hot water heating seems to be suspect. The idea is the boiler modulates that is the flame turns up/down and the radiators gradually turn on/off however the British government said new builds need a control system where you can select which part of house is heated, and the cheap method is two thermostats and two motorised valves.
However this means heating is turned on/off, and for the boiler to work at max efficiency it needs to turn up/down and the best way to control up down is with a connection to ebus, but is seems only EPH produce wall thermostats which will work as master/slave with a zoned house, and they don't connect to the TRV, well why would they when designed to work with zone valves?
So the only way to use is with a heat store, so boiler keeps heat store warm, and the heat is drawn from heat store when required, this also means solar and solid fuel and heat the water as well as main boiler.
The problem is the price, brother-in-law says his added 20k to price of house. Son fitted UFH but really it is just a heat sink for the aga stove, if too much hot water is produced it heats bedroom, and it is not connected to main boiler.
However this is suppose to be an electric UFH section, and you don't have motorised valves on an electric system, there are two basic types, one uses simple resistance wire, the other uses a special chemical which increases resistance as it warms up so is to some extent self regulating.
