LG UM36R (36,000 BTU, 10 kW) - ducted indoor unit 270 mm high for halls and workshops

The UM36R: a 10 kW ducted unit

The UM36R is a ducted indoor unit of LG's R32 semi-industrial series rated at 10 kW cooling and 10.8 kW heating. The dimensions are 1250 mm wide, 700 mm deep and 270 mm high; the casing is metal with plastic elements, the supply 220-240 V, 50 Hz, the refrigerant R32 and the compressor in the pair a Dual Inverter. The manufacturer country and country of origin are Korea and the warranty 24 months. Pipe diameters, the maximum pipe run and the height difference are not stated on the card, and we say so plainly: those values depend on the outdoor unit chosen, and we supply them from LG's combination table with the proposal. The UM series is no longer equipment for an office but machinery for halls, workshops and large open-plan spaces.

An 1250 mm casing: hangers and loads

A unit 1250 mm long with its coil and fans weighs substantially more than the CL series models, and its suspension is calculated separately. Four threaded rods with vibration isolators are fixed into the slab with anchors rated for the weight with a safety factor; fixing into plasterboard or into a suspended ceiling is out of the question. Before installation it is checked that there is no reinforcement, services or voids at the fixing points, and where necessary a frame of profile is built to spread the load over several points. Levelling the unit is mandatory to within a few millimetres: a tilt away from the drain outlet makes the tray overflow and leak onto the ceiling. Access for installation is planned in advance too - a unit this long will not pass through a standard 450 by 450 mm hatch, so it goes in before the ceiling is closed up.

A duct network for 10 kW

The airflow of a 10 kW unit calls for a main duct of 400 by 200 mm or more, or 315 mm round and up, and six to eight supply grilles distributed around the space. The return duct is made no smaller: often two or three large grilles with filters in different parts of the hall, so that air returns evenly rather than being drawn from one point. Velocity is held within 5-6 metres per second in the main duct, 3-4 in the branches and 2-3 at the grilles: exceeding these produces noise audible in the hall even against background chatter. Balancing with airflow measurements at each grille is mandatory, and the branch dampers are set to the real load rather than symmetrically. The high static pressure of this series allows long mains - 15-20 metres with several bends is normal geometry for it rather than the limit of its ability.

High static pressure in an industrial space

In a workshop, a warehouse or a sports hall the ductwork is often left exposed: the duct runs openly beneath the ceiling, and these are exactly the conditions where the UM series comes into its own. A main duct can be run the full length of the space, delivering air through nozzles or long-throw grilles into the zones that need it - above workstations, above a checkout line, above a seating area. That approach makes it possible not to cool the whole volume of a 5-6 metre high space but to work with the lower zone where people are: the saving is obvious, because cooling the air under the ceiling is pointless. For exposed runs, ducts with insulation in a protective facing are used, or they are painted to match the ceiling - in halls that is a normal design decision. A layout like this has to be designed with the throw of the air stream calculated, and we do that from the actual dimensions and height of the space.

Choosing the outdoor unit: one phase or three

There are two outdoor units of matching output for the UM36R: the single-phase UU36WR (item 1816) in a 950 by 1380 by 330 mm casing and the three-phase UU37WR (item 1820) in a lower 950 by 1170 by 330 mm casing. The difference is not in the cooling but in the electrics: the single-phase unit draws 15-17 A from one phase, the three-phase one 5-6 A from each of three. If the site has three phases the choice is obvious: thinner cable, lower losses, no imbalance and a lower casing that is easier to place. The single-phase variant is taken where three phases are absent and bringing them in is expensive; the authorised capacity is then checked, because 4-4.5 kW of system consumption is a substantial share of a domestic service. We verify the final pair against LG's compatibility table and state the exact pipe diameters and maximum run for the chosen combination.

Operation: filter, access, schedule

The filter in a unit of this output has a large area, but a great deal of air passes through it: in a sales floor or a workshop it clogs in weeks rather than months. The cleaning schedule is set from experience: the first look comes after a month of operation, and the interval is then planned from its condition - for a dusty production space that may be every fortnight. If the space is tall, access to the unit and the filters needs a ladder or a platform, and that question is settled before installation: a unit you have to reach with a lift never gets serviced. Once a year the system's readings are taken: pressures, superheat, currents, inlet and outlet temperatures - this reveals refrigerant loss or a fouled coil before a failure. The drain tray and line are checked before every season: a blocked tray in a unit above a suspended ceiling announces itself as a stain on a tile.

Which jobs it fits and where it is out of place

The UM36R suits a space of roughly 80-110 m² with a ceiling up to 3.5 metres, or a taller hall sized by volume: a sales floor, an open-plan office, a sports hall, a production area, a restaurant room. Its main strength is the ability to work with a long branched network, so it is taken where air has to be delivered to several distant zones. Where the model is out of place: spaces with less than 380-420 mm of void; a two-grille layout, where high static pressure and a large casing are superfluous; spaces with several zones needing different temperatures. For a warehouse or workshop with doors standing open, comfort cooling does not work - zone solutions above the workstations are calculated there instead. And if more than 10 kW is needed, the series offers the UM42R (item 1831) at 12 kW and the larger models.

How it differs from neighbouring models in this catalogue

The CM24R (item 1829) is 7 kW medium-static in a 900 mm casing: a step down for a smaller space. The UM42R (item 1831) is 12 kW in the same 1250 by 700 by 270 mm casing, while the UM48R (item 1832) at 13.5 kW and the UM60R (item 1833) at 15 kW are 360 mm high. If there is no suspended ceiling, 10 kW is available from the UT36R cassette (item 1838) at 840 by 840 mm or the UV36R ceiling-suspended unit (item 1844), 1600 mm long, which mounts in the open beneath the ceiling. The outdoor units for this model are the UU36WR (item 1816) for one phase and the UU37WR (item 1820) for three. All three types of 10 kW indoor unit work with these same outdoor units, so the choice of type remains a question of the space rather than of the circuit.

Describe the space, the ceiling height and the zones to be cooled - we will size the duct network for the UM36R and select an outdoor unit to match your supply.