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REFRIGERATION

Troubleshooting

Fridge drain pipe blocked

Every defrost cycle melts the frost on the evaporator, and that water must leave the cabinet through a small drain. In commercial kitchens that drain picks up food crumbs, flour, rice grains, vegetable trimmings and the slime that grows in still water. Once it narrows, water backs up under the evaporator, overflows into the cabinet, refreezes on the coil or leaks onto the floor. In monsoon months there is more water to drain, so a partly blocked drain that coped in winter may overflow in July. A blocked drain is one of the most common and easiest faults to prevent.

First, check these

  1. Look for water pooling on the cabinet floor, under the evaporator cover or in the bottom tray.
  2. Find the drain opening, usually at the bottom of the evaporator drip tray at the back of the cabinet.
  3. Check whether the drain outlet or evaporation tray outside the cabinet is dry even after a defrost; dry often means blocked.
  4. In freezers, check for ice in or under the drain opening.
  5. Check whether the unit is level with a slight backward tilt. A cabinet tipping forward sends defrost water towards the door instead of the drain.

Likely causes

  1. 1. Food debris in the drain opening

    You can check this

    Signs: Visible crumbs, grains or peel at the drain hole; water pooling after defrost.

    Fix: Isolate power, remove debris from the opening with gloved fingers or a soft brush, and flush the drain with warm water. Clean the drip tray at the same time.

  2. 2. Slime or algae growth in the drain line

    You can check this

    Signs: Slow draining, musty smell, jelly-like deposits at the drain outlet.

    Fix: Flush with warm water and a mild, food-safe cleaner, then clear water. A soft, flexible drain brush helps. Repeat as part of regular cleaning.

  3. 3. Drain hose kinked or crushed

    Technician job

    Signs: Drain clear at the top but water still backs up; unit recently moved or pushed against a wall.

    Fix: If the hose is visible and reachable without removing panels, straighten it. Otherwise a technician should re-route or replace it.

  4. 4. Frozen drain in a freezer

    Technician job

    Signs: Ice plug at the drain, water refreezing on the coil or the cabinet floor after defrost.

    Fix: A technician should check the drain heater and defrost settings. Pouring hot water down a freezer drain is a temporary fix at best.

  5. 5. Evaporation tray full or misplaced

    You can check this

    Signs: Water under the unit near the back, tray full, tray out of position after cleaning.

    Fix: Empty, clean and correctly reposition the tray so the drain hose discharges into it.

  6. 6. Unit not level

    You can check this

    Signs: Water collects at the front of the cabinet floor or runs out under the door even though the drain itself is clear.

    Fix: Adjust the feet so the cabinet is level side to side and tilts very slightly back towards the drain, then lock any castors.

When to call a technician

Call a technician if water keeps backing up after you have cleaned the drain opening and flushed it, if the drain line is out of reach behind panels, or if a freezer drain refreezes after each defrost. Add drain cleaning to your weekly or fortnightly cleaning schedule, and more often in busy kitchens during the monsoon.

Isolate power before cleaning drains and trays, because water may be close to wiring and fans. Do not push sharp wires or skewers into drains; they can pierce the drain line or evaporator, and hydrocarbon refrigerant (R290 or R600a) is flammable. Leave panel removal and sealed-system work to trained technicians.

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