It is imperative with any wood floor installation over UFH that there is a probe in each control area linked to room stats that have a built in floor temp limit function set to no more than 27 deg C. This is standard practice detailed in the relevant British standard and adhered to by any reputable UFH designer and installer. And this is an example of a suitable stat:- https://www.underfloorshop.co.uk/product/heatmiser-touch-thermostat-white/ - note it specifically mentions ‘floor temp limit protection’ in the tech spec list of functions. A stat with the option of a remote temp sensor is not sufficient – it must have a temp limit function. As to fitting on grooved chipboard/foam with small bore pipes in the grooves, we do not recommend this as it is very difficult to get an even surface temp. If this cannot be avoided, we would suggest that a dense cement board (‘Dry screed’ such as Gypdeck) of a minimum thickness of 18mm is laid over the UFH and the wood floor can then be bonded to this. In addition to this the water in the pipes should not be run at no more than 38 deg C. We would always recommend full bonding of wood floors on UFH, although technically it is possible to float the floor as long as sufficient expansions gaps are left, the areas are not more than approx. 5m square and there are expansion breaks in doorways. Either way there must be a probe to sense/limit the underside of the flooring to 27 deg C.