This also applies to a UH3
If you have a UH8 where the zone lights are coming on along with the valve, however the pump and boiler are not triggering, it is suggesting there could be an issue with the end switch of the valve in which the valve will need to be replaced. An electrician can test this by putting a link wire between OR and GR on the UFH Valve terminal on the UH8. If the boiler triggers then the valve will need to be replaced.