UMC Heating Controller

The UMC2 (Universal Managment Controller) is a controller is part of the Polar Bear Design HVAC control system and typically used with the Zentium or Ursium room thermostats. The UMC is used to interface with services such as underfloor manifolds, electric mats, towel radiators and pumps / boiler demands. It can be used as a slave device, but also act as a master device ensuring a stand-alone system can run autonomously.

Technical Features

  • 8 Zone Underfloor Manifold Controller
  • Dedicated Pump / Boiler relay switch
  • up to 8 x Remote 10k3 Probe Inputs
  • up to 8 x Digital Volt Free inputs
  • Modbus Communications Interface

UMC Modes


When the UMC is running in slave mode all the IO and relays are available as control points to a higher-level control system. This system could be another UMC or BMS or AV control system.

Mini Master

The mini Master mode is ideal for MDU installations or installations where fast self-configuration deployment is desirable. When a single UMC is on the modbus, it will scan for Zentiums and automatically program its own relay outputs and pump demand, based on the services configured in the Zentium and if the zones are wet or electric.

Max Master

The Max master mode acts as a full master for larger stand alone systems. When the polar bear design HVAC system has been configured a single UMC is then set to Max master mode and it will manage communications to the Zentiums and other UMCs on the Modbus network.

Pump Outputs

The pump output is a relay that can either be triggered directly or automatically controlled depending on how the services are configured. A delay can also be attached to the pumps output demand allowing an actuator time to fully open before triggering the demand on the pump / boiler. For example if a Zentium has the main zone configured as wet under floor and the 2nd zone (en-suite) configured to electric. The pump demand will only be activated when zone 1 has a heating demand.

Remote 10k3 Sensors

These inputs are only avalable on the 001 & 003 models. The temperatures recorded by these are then presented on in the Modbus register tables. Each temperatrue input also has individual calibration capabilities.

Digital Inputs

The digital inputs are presented on the Modbus register tables. Some special features are pre-programmed into the unit depending on the UMC mode is running. e.g. in Mini Master mode for MDUs one digital input can automatically switch the Zentiums into different Operational Modes e.g. Auto, Heating Only, Cooling Only, Away.

Speed Boost

When used with the Zentium Pro thermostat the UMCs have the ability to intelagently trigger demand setting by monitoring the data on the network. This improves responses times significantly as the UMC will see a request and response to data on the network and react instantly. This means a higher level control systems don't have to interpret priority communications which can cause unnecessary delays.

Fail Safe

When the UMC is sniffing the network it will automatically recognises when a Zentium has gone offline. In this scenario the UMC will automatically fail SAFE and turn OFF any demands that may have previously been generated by that zentium.

Model Number

UMC-MB4-001 DC & AC Rated Pump output + digital IO + temperature sensor inputs

UMC-MB4-002 DC & Volt Free Rated Pump output + digital IO

UMC-MB4-003 DC & Volt Free Rated Pump output + digital IO + temperature sensor inputs

Temperature Sensor


With configurable resolutions of 0.1, °C/°F

Accuracy ±0.5°C ±1°F

Sensor / Probe Support

4no. 10k3 remote probe inputs (001 & 003 models only)

4no. Digital Volt Free inputs


Actuator / Zone Output Relays

8no. 24v DC @ 300 mA maximum each output – 2A maximum total actuator load.

Pump Relay Output

1no. 240v AC @ 60 watt (UMC-MB4-001)

1no. 24v DC @ 60 watt or Volt Free (UMC-MB4-002 & 003)

Master Mode

Device can be set to master mode to communicate with other Polar Bear Products

Slave Mode

Device acts as slave address 1 – 15 & 17 - 32


Modbus Sniffing mode to respond to other Polar Bear Products



18 – 28v DC – 140mA (excludes power for the actuators)

Actuator Input Supply: 24v DC @ 2A minimum

Typical Power Consumption

110mA / 0.85 W @ 24v DC (excludes power for the actuators)

Test conditions: All features enabled, with external probes fitted and all relays activated


IP20 Rating, to be used indoors only.

Mounting within a consumer panel or breaker panel with integrated DIN rail


Ambient operating temperature: -5 °C to 45 °C, (23 °F to 113 °F)

0% to 80% non-condensing relative humidity. Indoor use only.

Max Pollution Degree: 2


SELV/PELV/NEC® Class 2 wiring connects thermostats to other devices on the Modbus link.

Mode: RTU Framing (JBUS)

Baud Rate: 9600, 19200, 57600 & 115200

Byte Format: 8N1

Modbus RTU

ESD Protection

Meets IEC 801-2. To withstand 15 kV electrostatic discharge without damage or memory loss.


Internal EEPROM is rated for 100,000 writes (non-volatile configuration only)

Power Failure

Features marked as non-volatile are saved to internal EEPROM memory and will be restored after power is returned.


35mm Standard DIN Rail mount




Modbus & DC Power Terminal (x4pin) accepts 28AWG to 18AWG wires

Remote probes Terminal (x8pin) accepts 28AWG to 18AWG wires

Digital Input Terminal (x8pin) accepts 28AWG to 18AWG wires

Pump / Boiler Terminal (x6pin) screw terminal L.N.E 20AWG to 16AWG wires

Actuator Input & Outputs Terminal (x18pin) push fit 20AWG to 16AWG wires

Bootlace Ferrules to be used on all stranded cabling

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