Frost has built up in a slab across the back wall and the drawers have frozen into their runners.
Usually: On a frost-free upright the defrost heater under the evaporator has gone open circuit, or the thermal cut-out sitting above it has tripped for good, so frost is never melted away during the defrost cycle.
On the visit: We take the back panel off, meter the heater and the cut-out for continuity at the loom connector, clear the evaporator under controlled heat and fit replacements where either reads open.
You defrost the whole freezer by hand, it behaves for a few weeks, then the ice comes straight back.
Usually: The defrost sensor or bimetal is reporting a temperature that stops the cycle ever starting, or the control is simply not calling a defrost.
On the visit: We read the sensor's resistance against its true temperature, force a defrost at the control and watch what actually switches on, then change whichever link in that chain is broken.
The freezer runs almost without stopping, there is condensation round the door and your electricity use has crept up.
Usually: The door seal has hardened, torn or lost its magnetic pull, or the door has dropped on a worn hinge, so warm damp air is drawn in all day and freezes on the coldest surface it finds.
On the visit: We close the door on a strip of paper all round to find where the grip has gone, adjust or replace hinges where the door has sagged, and fit a new seal where the old one will not seat.
The door-open alarm keeps sounding, or the warning light stays on with the door pushed firmly shut.
Usually: Usually the door or lid switch has failed, or a ridge of ice on the seal face is holding the door a millimetre or two proud; sometimes the alarm sensor itself has drifted.
On the visit: We watch the switch as the door swings closed, clear ice off the seal face and the cabinet lip, compare the alarm sensor against our own probe, and replace the switch or sensor once the fault is proven.
The dial or display says the freezer is cold enough, but ice cream is soft and food at the edges of the drawers has gone slack.
Usually: The cabinet sensor or thermostat has drifted out of calibration, or the condenser at the back has matted up with dust and pet hair so the heat cannot shed.
On the visit: We take our own readings at the top and bottom of the cabinet, compare them with what the control believes, clean the condenser and check the clearance behind the appliance, then change the sensor or thermostat where the two disagree.
One drawer or shelf sits far warmer than the rest, or there is a ticking, grinding rattle from the back that stops the moment you open the door.
Usually: The evaporator fan motor has failed, or the blade is striking frost that has built up around it, so cold air is no longer being pushed round the cabinet.
On the visit: We hold the door switch in so the fan runs on test, check the supply arriving at it and whether the blade turns freely once ice is cleared, and fit a replacement motor where the winding is open or the bearing has collapsed.
Water pools in the bottom of a chest freezer, or runs out onto the kitchen floor after a defrost.
Usually: The drain plug at the base has been left out or is not seated properly, or the drain channel is blocked with debris and ice so meltwater has nowhere to go.
On the visit: We clear and flush the drain through, refit or replace the plug so it seals, and check the lid seal, counterbalance and cabinet level, since a lid that will not sit square keeps making the ice that keeps making the water.