2026-09-21 · AmmoniaEquip Engineering
“Ammonia chiller repair” is the second-highest impression query on this site. Operators type it when a room will not hold temperature. Vendors hear “buy a compressor.” The chiller is the whole circuit. Most first-day findings are not a dead machine.
Walk the room first. One iced coil and three dry coils is an evaporator or defrost problem. High discharge pressure with dirty condenser tubes or dead fans is airflow, not a weak piston. A shaft-seal weep with clean oil and stable pressures is a seal job, not a rebuild. Write the pressures down before anyone opens a flange.
Non-condensable gas is the quiet capacity thief. A tired air purger will dump ammonia with the air and still leave the condenser “full.” Plants then raise head pressure, the compressor looks tired, and someone orders rotors. Repair the purger and the packing glands first. We have restored rooms without touching the compressor.
Controls lie in both directions. A slide valve that is mechanically stuck looks like a software fault. A sensor that reads 4 °C high will run the plant like a different duty. SCADA that has never been acknowledged is not a diagnosis. We check position feedback, solenoid voltage, and the last set-point change before we quote an overhaul.
When the compressor is actually the fault: metallic oil, liner knock, lost capacity at a proven 100% slide, or a seal that weeps after a recent misalignment. Then the job moves to the overhaul or refurbished-machine pages. The chiller still needs leak detection and a staged load-up after the machine is back.
Food and beverage plants — the same sites on our project list — cannot wait for a theory. Isolation, PPE, and a written “what we will open first” matter more than a catalogue. If you only have a smell and a warm room, start with detection and the purger. If you have hours, a nameplate, and metallic oil, start with the compressor.
That split is why this article exists separately from the overhaul guide. Search for chiller repair when the room is the mystery. Search for compressor overhaul when the machine has already confessed.
Questions we hear
Is an ammonia chiller the same as an ammonia compressor?
No. The compressor is one component. The chiller is compressor plus condenser, evaporator, vessels, purger, and controls. Repair the limiting part.
Why does my plant smell of ammonia if the compressor is running?
Glands, unused purge points, and the purger stack often leak before the shaft seal. Running does not mean leak-tight.
Should I replace the packaged chiller?
Only if vessels or coils are finished. A sound package with a tired compressor wants an overhaul or a remanufactured drop-in, not a new plant.