Air conditioning not working?
Start here. Pick the symptom that matches yours and we'll walk you through the likely causes, what you can safely check yourself, and what a repair actually costs. Written by F-Gas engineers who fix these across the West Midlands every week — not a call centre.
Six checks before you call anyone
- Mode is set to cooling (snowflake) — not heat, dry or fan
- Setpoint is below the current room temperature
- Filters are clean — slide them out and look
- The outdoor fan is actually spinning
- The isolator switch and consumer unit breaker are on
- Nothing is blocking the indoor unit or the outdoor unit's airflow
Roughly one in four "broken" units we're called to is one of these six. No charge for telling you that over WhatsApp.
What's it doing?
It's running but blowing warm
Mode and setpoint checks, low refrigerant, failed fan motors and capacitors — plus what each repair costs.
Read the guide →Water is dripping from the unit
Blocked condensate drains, dirty filters and frozen coils. What you can safely fix yourself.
Read the guide →There's an error code on the display
LG, Daikin, Mitsubishi and Samsung codes decoded — and which ones mean you have a refrigerant leak.
Read the guide →It smells musty, sour or burning
What each smell means, whether it's a health risk, and how a proper coil clean stops it returning.
Read the guide →It's rattling, buzzing or humming
Every noise decoded — which sounds are normal, which mean a failing part, and which mean switch it off now.
Read the guide →It keeps turning itself off
Short cycling, protection trips, tripping breakers and oversized systems — and what each fix costs.
Read the guide →The remote or app won't work
Battery, receiver and pairing checks — plus the hidden manual button that runs the unit without a remote.
Read the guide →Repair costs, up front
| Job | Typical cost |
|---|---|
| Drain flush (leaking unit) | £90 – £140 |
| Antibacterial deep clean | £120 – £180 |
| Start capacitor replacement | £140 – £220 |
| Outdoor fan motor | £180 – £340 |
| Leak find, repair and recharge | £280 – £550 |
| PCB replacement | £220 – £400 |
Fixed diagnostic fee, waived if you go ahead with the repair. Any brand, domestic only.
When repair stops making sense
Under 8 years old with a repairable fault: fix it. Over 12 years old with a seized compressor or a major leak on older refrigerant: a new inverter system usually pays for itself, running around 30–40% cheaper. We'll tell you which side of the line you're on before you spend anything — see our running cost calculator if you want to compare.