Ask The Expert: Refrigeration Cycle

Offered By MTSea Air Conditioning S.L.
  • Mark Critchley
  • Company Director and Lead Engineer
  • +34 660 84 68 99

Mark Critchley

Why doesn’t my freezer reach -22°C?

A freezer that is designed and built to achieve -15°C will never reach -22°C. Check the design parameters.

The chef has ordered 100kg of fresh meat, is this OK?

Quite likely not, you are asking industrial capability of a yacht installation. Best to either add small amounts or ask your supplier to pre-freeze it.

Why is there condensation on the outside of my freezer?

Intact insulation contains the cold inside the box. Condensation outside could be a sign of damaged or aged and deteriorating insulation.

Custom built refrigeration system on bridge

What basic checks can I do?

Regular visual checks of the system; look for changes and damage. Take note of fluctuations in temperature, know what is normal. Clean sea-water filters weekly or daily if you are somewhere where you can pick up a lot of debris. Clean air filters monthly.

Does the system need to be professionally serviced?

A professional service will include checking refrigerant pressures. A low-pressure reading can give you an early warning of a leak. Handling refrigerant including checking pressures requires refrigeration training.

What checks can I do if the system is performing poorly?

  • Does the unit have electrical power? Has the breaker tripped?
  • Has the door been left open?
  • Is the evaporator fan clear of obstruction
  • Is there water flow? Are the filters blocked? Is the pump running?
  • Is the defrost heater working?

How long should a refrigeration system last?

The answer to this varies greatly depending on level of use and the quality of the system purchased but expect between 7 and 12 years. A major indicator of needing a whole new system is where one or more major components has failed through age.

Why would the system be low on refrigerant?

A refrigeration system is a closed loop system; it should not ever require topping up. The reasons for low pressure are a new installation that was never charged properly, refrigerant has been lost due to interference or it has a leak. A top up is only legal and helpful in the first two instances. Repair of a leak is best done over 3 days so not the day before charter.

MTSea gauge

Why do the evaporators ice up?

Icing is caused by warm, moist air getting inside. The most common cause of this is frequent opening of the door or leaving the door open.

Another common cause is damaged or badly fitting door seals. Check them for splits and tears or local modifications. There should not be an air gap anywhere on the seal.

What causes a high-pressure alarm?

Most commonly this is caused by a lack of air or sea-water-cooling. Check filters and flow.

About this expert

MTSea Air Conditioning S.L. is a marine refrigeration and air conditioning company based in Palma de Mallorca specialising in yachts of all sizes. The company is led by Mark Critchley, who is a career engineer with fifteen years' yacht engineer experience and now specialises in air conditioning refrigeration. He has a passion for making things work properly and particular interest in custom refrigeration design.

The company supplies all marine manufacturers, installs replacement systems, services and repairs existing systems and undertakes problem solving on long standing issues. It can also undertake the in-house custom design and installation of fridges, freezers, chilled garbage lockers and wine fridges.

Find out more about this expert and contact them today.


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