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REFRIGERATION

Troubleshooting

Frost building up on deep freezer walls

Most chest deep freezers are manual-defrost. Their cooling tubes sit behind the inner walls, and any moisture that enters when the lid opens freezes onto those cold walls. Some frost is unavoidable. The question is how fast it builds. A freezer opened a few times a day in a dry month may need defrosting only occasionally; one opened every few minutes in a monsoon-season ice cream parlour can frost up in weeks. Frost is an insulator, so a thick layer makes the compressor work harder, raises running costs and can leave product warmer than −18 °C.

First, check these

  1. Measure the frost thickness. Once it is around 5 mm, or whatever your manual advises, plan a defrost.
  2. Note where the frost is thickest. A heavy patch near one corner or along the lid edge points to a seal leak there.
  3. Close the lid and check it sits flat and the gasket touches all round. Slide a strip of paper in at several points; it should grip.
  4. Check whether the freezer stands near an open door, AC outlet or wash area where humid air flows over it.
  5. Check when the freezer was last defrosted. Writing the date on a label on the lid makes it easy to see whether frost is building faster than usual.

Likely causes

  1. 1. Frequent or long lid openings

    You can check this

    Signs: Even frost across the walls, heaviest in busy months; staff leave the lid up while picking stock.

    Fix: Organise stock in baskets so items can be found quickly, keep a stock list on the lid, and train staff to close it between picks. Glass-top units let customers see before they open.

  2. 2. Lid gasket leaking

    You can check this

    Signs: Frost or ice ridge concentrated along one edge or corner, gasket split, flattened or pulled out of its groove.

    Fix: Clean the gasket and the cabinet rim, check the lid hinges and counterbalance, and replace a damaged gasket with the correct part.

  3. 3. High ambient humidity

    You can check this

    Signs: Frost builds much faster in monsoon, in coastal cities or near dishwash areas.

    Fix: Locate the freezer away from steam and open doors, keep the lid shut, and defrost more often during humid months.

  4. 4. Warm or uncovered product loaded

    You can check this

    Signs: Frost spikes after loading fresh product or uncovered trays; steam visible when loading.

    Fix: Load only pre-chilled or frozen product, cover it, and avoid loading hot items.

  5. 5. Lid hinge or alignment fault

    Technician job

    Signs: Lid does not stay closed under its own weight, springs up slightly, or sits unevenly.

    Fix: A technician should adjust or replace the hinges or lid. Do not force the lid with weights.

When to call a technician

Frost on its own is a housekeeping task. Call a technician if frost builds unusually fast despite good habits, if the lid will not seal after cleaning, if the freezer will not reach temperature after a full defrost, or if you see oily marks or hear hissing after defrosting, which could mean a damaged wall tube.

To defrost, move stock to another freezer or insulated boxes, switch off and isolate power, open the lid and let frost fall away on its own. Use plastic scrapers only. Never use knives, ice picks, hot-air guns or open flames; the refrigerant tubes are just behind the inner skin, and hydrocarbon refrigerant (R290 or R600a) is flammable.

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