LG Therma V R290 Combi Unit Installation Guide

For homes that need both space heating and domestic hot water, LG's Therma V R290 Monobloc Combi Unit brings the key components together in one floor-standing cabinet. With a built-in 200-litre Duplex stainless hot water tank, it provides space heating, cooling, and domestic hot water without the need for a separate tank.

The unit connects to an R290 Monobloc outdoor unit through water piping only, so no on-site refrigerant work is required. Its 600 × 600 mm footprint and rear pipe connections also make it practical for kitchen and utility spaces, while providing the access needed for installation and servicing.

This guide takes you through the installation process from positioning and water piping to electrical wiring, system configuration, and commissioning.

* This guide is a visual overview to accompany LG's installation video. It doesn't replace the full installation manual, and installation must be carried out by a qualified professional in line with local regulations.
* This guide covers the 2 zone model of the LG Therma V R290 Monobloc Combi Unit. Installation steps may differ for the 1 zone model.

With the right unit identified, the first job on site is preparing where it will go. Before moving the unit into position, confirm the floor is solid and level, drainage is accessible, and the required service clearances are met. The Combi Unit is a floor-standing cabinet weighing roughly 131 kg, so the base and its surroundings matter for safety, drainage, and future maintenance access.

2-1. Prepare location:
• Solid, level floor able to bear the filled unit's weight — remember the 200 L tank adds significant load once charged.
• Waterproof floor surface with access to household drainage.
• No flammable materials nearby.
• Nothing in front of the unit that would block access.

2-2. Confirm minimum clearance:
• Rear: 100 mm
• Right side: 500 mm
• Top: 300 mm
• Front: 600 mm

Now that the space is ready, it's time to move the unit in and open it up for the connections ahead. Because the Combi Unit is floor-standing rather than wall-mounted, it tilts into position rather than hanging on a bracket — and given its weight, this is a two-person job.

3-1 Move the unit into place:
• Work with two people, holding the bottom and rear handles.
• Tilt the unit backward to guide it safely into its final position.

3-2. Opening Up the Unit for Installation:
• Loosen the bottom screws to lower the control panel (HMI).
• Release the screws at the top of the indoor unit and detach the front panel.
• Unscrew the fixings connecting the control box to the side panel, then open the control box.

With the unit in place and open, the next stage is the plumbing — connecting the water circuits that carry heat around the system. The Combi Unit uses clip-type, plain-end connectors, so pipes press-fit into place rather than being threaded. That makes them quicker to fit and easy to take apart later for servicing. Work through the ports using the port map on the unit as your guide.

4-1. Connect the circuits:
• Direct circuit — the primary heating/cooling circuit (e.g. radiators).
• Mixing circuit (2nd circuit) — the second circuit, typically underfloor heating at a lower temperature.
• Domestic hot water — connect the hot water outlet and the city (mains) water supply.
• Re-circulation — optional; if you're not using a re-circulation pipe, close the hole in the straight pipe.
• Outdoor unit — connect the flow and return pipes to the R290 Monobloc outdoor unit.

With the water side complete, we move to the electrical connections. The Combi Unit has two separate cable entries: Hole A for low-voltage and sensor cables, Hole B for power. Before you touch any wiring, switch off the power supply.

* All electrical work, including wiring of the indoor unit, backup heater, and protection devices, must be carried out by a licensed electrician in accordance with national wiring standards and LG’s official installation manual.

5-1. Routing Each Cable Through the Correct Entry:
• Hole A — communication (DC) and sensor cables.
• Hole B — power supply cables (indoor unit and backup heater).
• Use round pressure (ring) terminals at the power terminal block, and don't over-tighten the wiring — the control box still needs to open after the connections are made.

With everything installed and configured, the final stage is commissioning — the checks and tests that confirm the system is safe to run before you hand it over. Taking the time here catches installation faults early, and the Combi Unit's guided setup wizard makes the process straightforward.

7-1. Begin with the Pre-Start Checks:
• Confirm the charged water pressure reads between 2.0 and 2.5 bar, and never above 3.0 bar.
• Check that all air has been purged and the air vents are closed.
• Confirm the communication and power wiring are correct and properly separated.
• Verify all valves in the water circuit are open.

7-2. Running the Tests and Starting Up:
• Run the Backup Heater Wiring Test from the HMI setup menu to confirm the heater is wired correctly.
• Use the Commissioning Wizard to complete the installer settings and start-up in guided steps.
• Run the pump test from the service menu.
• Power the unit on ahead of first use to pre-heat the compressor before full operation.