Guides to the systems we install and service – splits, multi-splits, VRF and close control – covering unit types, refrigerant implications, the faults that recur and the maintenance that prevents most of them.
Unit types
| Type | Suits | Watch out for |
|---|---|---|
| Wall-mounted split | One room, cooling-led | Warm air from high on a wall is poor for heating |
| Floor / console | Rooms where heating matters as well as cooling | Takes floor space |
| Ducted | Where visible units are unacceptable | Needs void depth and careful duct design |
| Cassette | Open-plan with a suspended ceiling | Ceiling void depth, and condensate routing |
| Multi-split | Several rooms, one outdoor position | Shared capacity, and all units in the same mode |
| VRF / VRV | Multi-zone commercial | Large charge means F-Gas obligations |
| Close control | Server and comms rooms | Needs continuous duty rating and auto-restart |
The heating point on wall units is worth emphasising, because so many systems are bought for cooling and then used for heating. Warm air rises, so a unit discharging near the ceiling is working against physics. Floor or console units are considerably better if heating is a genuine part of the intention – see air conditioning vs a heat pump.
Refrigerants, and why they matter to the owner
The refrigerant in a system determines the owner’s legal obligations, future repair costs and how long the equipment remains economically supportable.
- R410A – high GWP, very widely installed from the 2000s, being phased out of new equipment. Existing systems keep running; recharging gets progressively more expensive.
- R32 – substantially lower GWP, the current mainstream for splits. Mildly flammable (A2L), which affects minimum room areas for a given charge.
- R290 (propane) – very low GWP, flammable, used in monobloc heat pumps and some self-contained units.
- R134a and R407C – high GWP, found in chillers and older systems.
CO2e = charge x GWP, and CO2e determines your leak checking obligations. Two numbers off the nameplate settle everything else – see R32, R410A and R290 and leak check frequency.
The faults that actually recur
- Dirty filters. Restricts airflow, reduces capacity, can ice the coil. User-cleanable and the highest-return maintenance task there is.
- Blocked condensate drains. Biological growth in the drain line, tray overflows, water down a wall or into a ceiling. The most common cause of visible damage from air conditioning.
- Fouled outdoor coils. Leaves and debris in the fins. The condenser cannot reject heat, pressures rise, efficiency falls and eventually it trips.
- Failed condensate pumps, where gravity drainage was not available. Moving parts in ceiling voids.
- Refrigerant loss at flare connections, which is a workmanship issue from installation showing up years later.
- Biological growth on the indoor coil, producing the musty smell.
- Fan blade damage or imbalance, producing noise complaints.
- Controls nobody understands, frequently after the person who set them up left.
Between them, dirty filters and blocked condensate drains explain a very large share of air conditioning service calls. Both are preventable, one is user-maintainable, and neither requires an engineer if they are dealt with routinely – see air conditioning servicing.
What every equipment page covers
- Unit type and typical applications.
- Refrigerant and charge, and the CO2e implications.
- Filter access and cleaning, because it varies and users need to know.
- Condensate arrangement and its known weaknesses.
- Common faults and what they usually turn out to be.
- Fault code families for that manufacturer.
- Parts availability.
- Service access quirks.
- Controls and BMS compatibility, for commercial equipment.
Each model page below is populated from what we actually find on the job – common faults, part numbers, service quirks and access notes – rather than from manufacturer literature. That takes time to accumulate and it is worth more than a rewritten brochure. Pages appear as the records support them.
Not cooling properly? Check the filters and look at the outdoor unit. Those two account for most of it and both are free.
Questions we get asked about this
Why is my air conditioning not cooling?
In order of likelihood: dirty filters, a blocked outdoor coil, wrong mode selected, or low refrigerant. The first three you can check in five minutes.
Water is running down the wall from the indoor unit.
A blocked condensate drain, almost always. Switch it off before it does more damage. It is a routine clean and it is the most common preventable fault there is.
What refrigerant is in my system?
It is on the outdoor unit nameplate, along with the charge quantity. Those two figures determine your CO2e and any legal obligations.
Will my R410A system have to be replaced?
Not because of the phase-down as such – it will keep running. What changes is the cost and availability of refrigerant if it ever needs recharging, which makes a future leak much harder to justify repairing.
Can I clean the filters myself?
Yes, and you should – monthly in heavy use. Lift the front panel, slide them out, rinse in warm water, and let them dry completely before refitting.
Which indoor unit type is best for heating?
Floor-mounted or console, because warm air rises and a high wall unit is working against that. Specify accordingly if heating is a real part of the intention.
Regulations and standards referenced on this page
- Regulation (EU) No 517/2014 on fluorinated greenhouse gases, as retained and amended in GB law — UK Statute Law Database
- Fluorinated gases (F gases): guidance for operators and engineers — Environment Agency / Defra
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