A set of plans for all ducting will have been issued to you by the company who will be installing the ventilation system. If you plan to install it yourself, you will need a mechanical and electrical (M&E) engineer to step in and supply a set of plans for the ducting: minimal pipe runs, minimal number of bends. You will also need advice on installation and get them to do the commissioning, all of this at a cost.
In ROI commissioning on all domestic ventilation systems has to be done by an independent person, i.e. the 2019 building regulations state it can no longer be the ventilation company that signs off on it.
In NI, the installers will provide the certification, but your certifier will also need to check that the installation is in accordance with the manufacturers instructions.
Your plumberwill take the lead on installing your heating system in stages; whether or not there is underfloor heating will determine when they start the process. Your plumber will coordinate this with your electrician and do the commissioning.
For air source heat pumps,the installer will make sure there is nothing obstructing the free passage of air around the unit as per the manufacturer instructions. Short pipe runs, with good insulation, from the units to where the heat is needed will reduce the risk of heat loss.
Manifolds are usually associated with underfloor heating, i.e. pipes going to a room and back to the central panel, but can also be used with radiators. This is necessary to be able to control each room with an individual thermostat.Some systems rely on one thermostat per zone (7), covering multiple rooms, but the more thermostats the more control.
Stats need to be away from radiators or other heat sources, and shouldn’t be close to one another, etc. Your installer will be able to advise; ona new build you can expect a set of plans from them.