serin labs
Multi-Zone Controller · Whole-system control In development
Control every zone from one place.
The Multi-Zone Controller connects to the communication wiring in a Mitsubishi multi-zone system and adds the complete installation to your smart home platform. Each indoor unit appears as a separate climate accessory, along with operating data that is normally available only through service tools.
Reservable now. We will email you when ordering opens.
Reserve yours Follow development on DiscordBefore you reserve
Will it work with your system?
City Multi, PUMY and M-series with a branch box do. Check by the model number on the outdoor unit’s label, not the indoor unit’s, or browse the full outdoor unit list.
CITY MULTI
VRF systems, including branch controllers. Wire in at the outdoor unit, at a branch controller, or at any supported indoor unit. Scales from a single outdoor unit to large installations with multiple outdoor units on the same bus.
PUMY / P-series
Light-commercial systems on the same two-wire transmission bus. Wire in at the outdoor unit's terminals.
M-series with a branch box
Branch box systems only. Wire in at the outdoor unit or the branch box. Ported outdoor units, where each head runs its own refrigerant lines back to the outdoor unit (i.e. MXZ-4C36NA), are not supported.
Single-zone unit? The Serin Controller is the right device.
Unsure about your system, or running an unusual mix such as City Multi indoor units on an M-series outdoor unit? Bring your outdoor unit model number to Discord.
How it connects
One connection covers every zone.
Connect the Multi-Zone Controller to the two-wire communication connection at the outdoor unit or branch box. On City Multi systems, you can also connect it at an indoor unit. The controller receives power through the same wire pair, so it does not require a wall adapter or separate power wiring. One controller covers the complete system.
Multi-Zone Controller
Outdoor unit or branch box
Indoor units, every zone
Multi-Zone Controller
Outdoor unit or branch box
Indoor units, every zone
Control
Control every indoor unit.
Each indoor unit appears in your smart home platform as a separate thermostat with power, mode, fan speed, and target temperature controls. You can adjust and automate each zone independently and view its current operating state.
A built-in web interface is also available on your local network for setup and a live system overview. Home Assistant is not required.
Operating data
View detailed system operation.
The outdoor unit tracks refrigerant pressures, valve positions, compressor current, and multiple temperatures. These readings normally require service tools. The Multi-Zone Controller reads them in real time and shows each reading separately in your smart home app.
HIGH-SIDE
208.4 psi
COMPRESSOR
58 Hz
ZONES CALLING
3 of 5
SUPERHEAT
8.6 °F
SUBCOOL
11.2 °F
- discharge + suction pressure
- LEV pulses, per branch
- superheat + subcool
- operating frequency
- compressor current
- fan step
- th1 / th2 / th3, per indoor unit
- discharge temperature
- room + setpoint, per zone
- mode · run/stop, per zone
- reversing valve + solenoids
- fault codes, decoded
Sensor set varies by outdoor unit model. Values shown are illustrative.
Technical specifications
Controller hardware
Enclosure, dimensions, and final connector layout are published when the production run is final.
Good to know
Frequently asked questions.
Does it replace my remotes or central controller?
No. It connects to the same communication wiring as your existing controllers. Your existing wall controllers, remotes, and any central controller keep working, and the Multi-Zone Controller shows their changes live.
Does it need Wi-Fi?
Yes. Wi-Fi connects the controller to your smart home platform and its built-in web interface. Communication stays on your local network; no cloud service or account is required.
How is this different from the Serin Controller?
The Serin Controller connects to an indoor unit's CN105 port, with one controller required per indoor unit. The Multi-Zone Controller connects once to the system's communication wiring and covers every zone, while also providing system-level operating data that CN105 does not carry.
Is installation invasive?
Installation requires two wires connected to the existing transmission terminals at the outdoor unit or branch box. City Multi systems also allow a connection at an indoor unit. The same connection powers the controller. Turn off power to the system before opening any equipment.
Will it work with the Serin Link?
Support for pairing with the Serin Link is planned, allowing one physical control to access every zone. Reserve either product for an email when ordering opens.
In development
Tell us about your system.
Share your outdoor unit model, the smart home platform you use, and the features you need. Follow Multi-Zone development and hear when ordering opens in the Serin Labs Discord.
Prefer an email when ordering opens? Reserve yours.