Cassette Air Conditioning

What is cassette air conditioning?

Cassette air conditioning is a system whose indoor unit sits in the ceiling, with only a flat grille showing in the room. Climate Flow Limited installs, services and repairs cassette air conditioning for restaurants, shops, offices, gyms and other commercial sites across London and surrounding areas.

A cassette unit is an indoor air conditioning unit set into the ceiling. Mitsubishi Electric describes its compact cassette as a square, slimline grille designed to fit snugly to the ceiling, blowing air out on all four sides (Mitsubishi Electric, Mr Slim 600x600 ceiling cassette). Its larger four-way cassettes offer 72 airflow patterns and can be used on ceilings up to 4.2 metres high, according to the manufacturer (Mitsubishi Electric, VRF ceiling cassette). The cassette connects by refrigerant pipework to an outdoor unit.

Where does a cassette suit?

A cassette suits a room with a suspended ceiling where wall and floor space are needed for other things: a dining room, a shop floor, an open-plan office or a gym. Mitsubishi Electric describes its compact cassette as ideal for office and retail. Mitsubishi Heavy Industries lists small to medium offices, retail shops, fitness centres and restaurants among the settings for its compact four-way cassette, whose 620 x 620 mm panel fits a standard ceiling grid (MHIAE, FDTC-VH compact cassette).

A cassette is not always the answer. We also fit other systems: we installed a Mitsubishi Electric split system in a newly refurbished retail unit in Hillingdon. We have also carried out VRF maintenance work for Energie Fitness Gym. The survey is where that choice gets made.

How much ceiling space does a cassette need?

The ceiling void a cassette needs depends on the model. Mitsubishi Electric states that one compact range fits ceiling spaces only 245mm high; other units need more. On a site survey the engineer lifts the ceiling tiles, measures the void and checks what is already up there: ductwork, cable trays, lighting and the grid itself.

The survey also plans three routes before a unit is chosen: the refrigerant pipework to the outdoor unit, the condensate drain (the pipe that carries away the water the unit collects while it cools), and the electrical supply.

What does a cassette installation involve?

1. Survey. The engineer measures the room and the ceiling void, agrees where the outdoor unit can go, and plans the pipework and drain runs.
2. First fix. Refrigerant pipework, the condensate drain and cabling are run through the ceiling void and out to the outdoor unit position.
3. Units in. The cassette is hung from the soffit (the structural ceiling above the suspended grid) and the outdoor unit is fixed in place.
4. Test and commission. F-Gas certified engineers pressure test the pipework, evacuate it (pump the air and moisture out before the refrigerant goes in) and commission the system (start it up and check it runs as designed).
5. Handover. You are shown the controls and where the filters are, and the work is recorded.

Disruption is mostly lifted ceiling tiles in the area being worked on. Where a site trades during the day, the work is planned around its opening hours.

How do I know my cassette needs attention?

• Water dripping from the grille, or stained ceiling tiles around the unit.
• Weaker airflow, or the room no longer reaching the temperature set on the controller.
• A new rattle, hum or clicking from the ceiling.
• An error code showing on the controller.
• A musty smell when the unit starts.

Never open the refrigerant circuit or add refrigerant yourself. In Great Britain, working on equipment that contains F gas without the correct qualifications is against the law.

What does a cassette service include?

Cassettes are fitted with air filters that remove airborne dust from the room, so cleaning the filters is part of every service. A service also checks the drain, the coils, the refrigerant circuit and the controls.

• Air filters cleaned
• Drain tray and drain pump checked and cleared
• Indoor coil and grille inspected
• Outdoor unit coil and airflow checked
• Refrigerant leak check, with the result recorded
• Controls and error history checked

Two legal points apply. In Great Britain, installing, servicing, leak-checking and decommissioning air conditioning that contains F gas needs the correct qualifications (GOV.UK, qualifications to work with F gas); Climate Flow's engineers are F-Gas certified. And air conditioning with an effective rated output of more than 12kW must be inspected by an energy assessor, with inspections no more than five years apart; the person who controls the system is responsible (GOV.UK, air conditioning inspections). A site with several cassettes may cross that threshold once their outputs are added together.

Cassette air conditioning for a restaurant on Orsman Road

More of our refrigeration and air conditioning jobs are on Our Projects.

Talk to Climate Flow about cassette air conditioning

We install and service cassette air conditioning from makes including Mitsubishi Heavy Industries, Mitsubishi Electric, Daikin, Fujitsu, Toshiba, Panasonic and Samsung, with 24/7 emergency callouts for breakdowns. Climate Flow Limited, 2 Engineers Way, Wembley, London HA9 0JS, covers London and surrounding areas. Call 020 3488 5452 to arrange a survey.

This guide is general information, not a survey or a quote for your site; every system is different, so an engineer needs to see yours before any work is priced.