What we replaced
We built new foundations under the air handling units. Each side now runs a Frascold Z50-168Y compressor with an RDYG 40 receiver, an oil separator and a suction accumulator, and two CJR-612424 air-cooled condensers per side went up on deck.
Piping and controls
We prefabricated the piping before fitting and took it through the hull in Roxtec transits. The system got a new electrical panel and Danfoss controls:
- KP 15 pressure switches for high-pressure protection and KP 5 for capacity and fan control,
- GBC shut-off valves and NRV 35 check valves on the liquid and return lines,
- 48 DM filter-driers, EVR 35 solenoid valves and TE 55 thermostatic expansion valves with no. 10 orifices.
Tests and commissioning readings
We tested the system for 24 hours with nitrogen at 20 bar, pulled a vacuum to -1 bar and charged it with 50 kg of R407C.
After start-up the compressors ran at 4.5 bar suction, 14 bar discharge and 8.5 bar oil pressure, with an evaporating temperature of +5°C. The high-pressure switch tripped at 22 bar. We recommended an oil change after about 24 hours of running.
We do the same kind of HVAC piping installation on vessels on newbuilds and during refits.
