Chiller AC running but barely cooling — what's wrong?
We're on district cooling and the AC runs constantly but the apartment stays warm — nothing like the cooling we had last year. Airflow seems okay, it's just not cold. What could cause a chiller system to run but not cool?
3 answers
Chilled-water systems fail differently to splits. Check in this order:
- FCU filter and coil. A clogged filter or dirty coil chokes cooling. Clean the filter first — it's the most common cause.
- Chilled-water control valve. Each FCU has a valve that lets chilled water through the coil on demand. If it's stuck closed or the actuator failed, the fan blows but the coil never gets cold water. Needs a technician.
- Air in the coil / low flow. Trapped air or a strainer blockage reduces flow; a tech can bleed and check it.
- Building-side supply. If neighbours are also warm, the district-cooling supply temperature or a plant issue is to blame — that's the provider's job.
If only your flat is warm, it's your FCU (points 1–3). If the whole tower is, it's point 4. If the FCU checks don't fix it and the building confirms the loop is fine, a water chiller service in Dubai can service the coil and valves properly.
Ours turned out to be a failed valve actuator on one FCU — fan running, no chilled water getting through. Quick swap once it was diagnosed.
If you want to move from 'it's barely cooling' to actually knowing WHY, there's a newer thread on reading a chiller's delta-T and approach temperature — the two numbers that reveal whether the plant (or your FCU) is genuinely performing or quietly fouled/starved. Worth a read if the cooling's weak but nothing's obviously 'broken' — the numbers usually point straight at the cause.
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