When do you use a VRF Single Port vs Multiport Branch Selector Box?What’s the difference between a single port branch selector box and multiport box? What does the branch selector box do? Which one requires more piping?The decision to use one or the other of these VRF branch selector box configurations is based on the site conditions and owner requirements. There are several factors to consider when laying out a VRF system and whether to use a multiport or single port branch selector box. What’s Happening in the VRF Branch Selector BoxThe branch selector box is where the magic happens in the way of diverting the refrigerant based on the space requirements. The VRF branch selector box is the traffic cop of the refrigerant, directing refrigerant flow. Depending on the call from the thermostat and fan coil, the heat recovery selector box will send either hot gas (Heating mode) or Low pressure liquid (Cooling mode) to the indoor fan coil.Each Branch Selector Box (even the name for the box is different amongst manufactures) operates slightly differently.
Mitsubishi’s VRF (2-pipe system) Multiport Branch Selector Box requires a condensate drain, while Daikin (3-pipe system) and others don’t require a drain. This is because of the difference of how the refrigerant is managed in the box. While Mitsubishi requires a drain on their branch selector, they only require two pipes from the VRF outdoor unit to the selector box, while other VRF/VRV manufactures require three pipes. You can see our.Using a system would allow you to have zones in both heating and cooling simultaneously.
One zone could be cooling while another is heating. With a VRF heat pump system this isn’t possible, as it’s either all zones cooling or all zones heating. VRF Branch Selector Box Size & Length of PipesWith a VRF multiport box, the is run from the outdoor unit to the multiport selector box, and then to each zone or fan coil will have a separate run of piping. Some manufacturers require two pipes while others require three pipes from the VRF outdoor unit to the multiport box.The refrigerant piping from the multiport selector box to the fan coil is a two-pipe homerun, but with multiple ports you need the space for lots of insulated refrigerant pipes with the ability to turn where needed.With a single port branch selector box, three main pipes are run from the VRF outdoor unit with three pipe branches to each single port branch selector box, and then on to the fan coils with two pipes.
Many zones can be fed from a VRF multiport selector box versus just a single zone being fed from a single port branch selector box.