How a two‑door fridge gets cold

1. A two-door fridge: freezer on top, fridge compartment below

First, take in the whole fridge: one side is cut away so you can see inside, and the other side still shows the outer casing. On top is the freezer, below it the fridge compartment, and both are wrapped in a layer of foam insulation that keeps the outside heat out. Behind the freezer sits the cold coil (evaporator), and at the bottom back is the compressor. Next, see how the fridge moves the heat out.

Go deeper: A two-door fridge: freezer on top, fridge compartment below

The cabinet has three layers: the painted sheet-steel outer casing outside, the white plastic inner liner inside, and foam insulation filling the space between them (the pale yellow in the cutaway), which cuts down the heat seeping in from outside. The condenser, anti-condensation pipe, capillary tube, suction line and drain tube are all buried in the foam, so you can't see them from outside.

Both doors have a door gasket all the way round the back. Its front section holds a magnet strip that grips the cabinet's steel front frame; the bellows section behind it can stretch and squash, so it still seals when the door is slightly out of line. A gasket that has hardened or split leaks air: warm, moist air gets in, frost forms along the door edge and the compressor runs non-stop.

2. A fridge moves heat

The refrigerant circulates non-stop in a sealed loop of tubing. It soaks up heat in the cold coil (evaporator) behind the freezer and gives it off in the condenser in the cabinet's two sides. Heat is moved from the inside to the outside, so the inside gets cold. Red is hot and high-pressure, blue is cold and low-pressure: follow the dots round the loop.

Go deeper: A fridge moves heat

On a pressure–enthalpy diagram (p-h diagram), one loop has four steps. ① Compression: the compressor does work, and the gas's pressure and enthalpy rise together. ② Condensation: at high pressure the gas first cools, then condenses into a liquid, giving off latent heat. ③ Throttling: in the capillary tube the pressure drops sharply. The enthalpy stays basically the same, but some of the liquid flashes into gas at once, and the temperature drops to the evaporating temperature. ④ Evaporation: at low pressure the refrigerant boils and soaks up heat. With R600a (isobutane) evaporating at −25°C and condensing at 40°C, the low pressure is about 0.58 bar and the high pressure about 5.3 bar (absolute): a ratio of about 9:1.

Energy is conserved: heat given off by the condenser = heat taken from inside the fridge + work done by the compressor. The coefficient of performance (COP) = cooling capacity ÷ power used. Between −25°C and 40°C the theoretical limit (Carnot) is about 3.8; a real household compressor manages about 1 to 2 [varies by model and operating conditions]. For example, a compressor drawing 80 W at a COP of 1.5 moves 120 J out of the fridge every second and gives off 200 J through the cabinet. That is why it is normal for both sides to be warm.

What follows is background knowledge. A refrigerant leak is uncommon in a household fridge (among fridges that have gone warm, fewer than two in ten cases are a refrigerant system fault). Even if it is repaired, opening the system lets in moisture and dirt, and a system holding R600a can't be brazed directly, so the fridge often fails again soon after. Fixes doesn't do refrigerant system repairs and doesn't recommend them: once the fault is confirmed, the technician issues a not-repairable report and recommends a new fridge.

In a small system with a capillary tube, the amount of refrigerant is very “critical”. A household fridge usually holds only a few dozen grams of R600a (see the rating plate), and a few grams more or less affects cooling. So when you charge refrigerant, pull a full vacuum first, then weigh in the rating-plate amount on a charging scale. Don't top up by guessing from a pressure gauge. R600a is a flammable refrigerant (safety class A3): when you repair, keep the area ventilated, keep away from flames, and use the right tools and procedures.

3. Compressor: squeezing the refrigerant hot

The black steel shell at the bottom back of the fridge is the compressor, the heart of the whole fridge. It squeezes cold, low-pressure refrigerant gas into hot, high-pressure gas. In the terminal cover on its side are the start relay (PTC) and the overload protector: they help it start and keep it from burning out. When it is cold enough, the compressor stops, and it starts again only once things warm up: watch the “Compressor” band under the chart switch on and off.

Go deeper: Compressor: squeezing the refrigerant hot

Household fridges most often use a hermetic reciprocating compressor: the motor and the piston are sealed together inside a welded steel shell. The returning suction gas flows straight into the shell and cools the motor windings. Compressor oil sits in the bottom of the shell, and suction and discharge each work through a reed valve. Each cubic metre of returning R600a (isobutane) gas carries away only about half as much heat as R134a. So for the same cooling capacity, an R600a compressor needs a bigger displacement. The two refrigerants use different compressors and different oils, so never swap one for the other.

Starting relies on the start relay (most often a PTC, short for positive temperature coefficient) plus the overload protector. When cold, the PTC has a low resistance (usually a few Ω to a few dozen Ω) and connects the start winding. Within a second or two of switching on, it heats up to a high resistance and cuts out the start winding by itself. The overload protector is a bimetal disc that snaps open if the current is too high or the shell too hot. After the compressor stops, the capillary tube takes a few minutes to let the pressures equalise, and the PTC also needs time to cool down. If it restarts before the pressures have equalised, the motor can't overcome the pressure difference: you hear a “hum”, the overload protector trips open with a “click”, and then it tries again. The gap depends on the protector, anything from a few seconds to a few minutes. With a faulty start relay, the compressor usually doesn't feel hot. A faulty start relay or a seized compressor makes the same sounds, so always take the start relay out and shake it: a rattle of loose, broken bits inside means the start relay is faulty. The overload protector rarely fails on its own, but it does happen. An inverter compressor has no start relay.

Testing the windings: the three terminal pins are C (common), S (start) and R (run). Normally S–R = C–S + C–R, and the start winding has a higher resistance than the run winding, usually 10-plus to a few dozen Ω [varies by model]. Every pin should show insulation in the megohm range to the shell. If the windings are fine but the compressor won't start, check the start relay, the overload protector and the voltage. If the start relay is fine but the compressor starts for a moment, stops again and its shell is hot, the compressor itself is more likely faulty (not repairable). The running current is usually under 1 amp [varies by model]. At room temperature the compressor runs about 30⁠–⁠60% of the time. If it runs non-stop, check for a refrigerant leak, poor heat shedding, the door gaskets and frost build-up.

4. Shedding heat: why the fridge's sides get warm

This fridge has no black condenser grille on the back. Its heat-shedding tubes (the condenser) are fixed to the inside of the outer casing on both sides and buried in the foam layer. A section of anti-condensation pipe is also buried behind the front frame. It runs round the freezer opening and the divider between the two compartments (the actual route varies by model), so no water droplets form on the front frame round the door. As the hot refrigerant passes through, it sheds its heat and slowly condenses back into a liquid, so it's normal for both sides to feel warm. Don't box in the sides and the top: leave room for air. Drag the “Room temperature” slider: the higher the room temperature, the longer the compressor runs.

Go deeper: Shedding heat: why the fridge's sides get warm

A skin condenser has its tubes taped with aluminium foil to the inside of the steel outer panels, with the foam layer right behind them. The whole side panel works as a heat sink, shedding heat by natural convection and radiation. The upsides: it doesn't gather dust easily, needs no cooling fan and leaves the back tidy. The trade-off is that it sheds heat less well, so the condensing temperature has to sit further above room temperature, about 10-plus degrees higher [approx.]. So it is normal for the side panels to feel a few to 10-plus degrees warmer than the room. It's only a problem if the compressor is running and the side panels aren't warm. Even so, the compressor area at the back can still collect dust and pet hair, which makes the compressor overheat: check it before judging a compressor problem.

Inside the condenser there are three stages. First the superheated gas cools, then it condenses at a fixed temperature, giving off latent heat, and finally the liquid is cooled a few degrees more: this is subcooling. With enough subcooling, only pure liquid enters the capillary tube. If the refrigerant is low, the condenser outlet still carries gas bubbles, and the flow through the capillary tube drops sharply. If the fridge's sides are jammed against walls or the top is piled with clutter, the condensing temperature and pressure both rise. Cooling capacity falls, power use rises and the compressor runs longer.

The anti-condensation pipe in the front frame round the door is usually a section of the condenser circuit (some models use an electric heater wire instead; the route and design vary by model). The reason is the dew point. Air at 30°C and 80% humidity has a dew point of about 26°C, so any surface colder than that collects water. The freezer door edge sits right next to the −18°C inner liner, so a hot pipe has to keep it warm. The skin condenser and the anti-condensation pipe are both buried in the foam layer, so a leak is very hard to repair in place. The usual approach is to seal off the original tubing and fit an external condenser instead [depends on the case] (background knowledge: Fixes doesn't do refrigerant system repairs). With the anti-condensation pipe bypassed, water may form along the door edge.

5. Capillary tube: the sudden pressure drop

The liquid refrigerant first passes through the filter drier, then squeezes into a capillary tube thinner than a toothpick. The tube is long and narrow, so at its outlet the pressure drops sharply to about 0.6 bar (below atmospheric pressure). The refrigerant boils at once and its temperature falls to about −25°C. For a long stretch the capillary tube is brazed to the suction line, and the two exchange heat.

Go deeper: Capillary tube: the sudden pressure drop

The capillary tube is a fixed throttle. Its inside diameter is usually about 0.6⁠–⁠0.8 mm and its length about 2⁠–⁠4 m [varies by model]; length and diameter together set the flow. The diameter matters enormously. As a rough estimate, for the same flow, the length needed is about proportional to the fourth to fifth power of the inside diameter. Make the diameter 10% bigger and the length must grow by about 50% to balance it again [rough estimate]. So a replacement capillary tube must follow the manufacturer's specification; you can't just cut any length.

The capillary tube is usually brazed to the suction line or runs inside it, forming a suction-line heat exchanger. Estimating with 40°C condensing and −25°C evaporating: without precooling, about 40% of the R600a (isobutane) has already flashed into gas as it leaves the capillary tube, and that gas can't absorb any more heat. With the suction line precooling the liquid, less flashes off, and each kg of refrigerant can absorb about 20⁠–⁠30% more heat [estimate]. At the same time the suction gas warms up to near room temperature, so the stretch of suction line near the compressor shouldn't frost up or sweat.

At atmospheric pressure R600a boils at about −11.7°C. To make it boil at −25°C, the pressure has to be below atmospheric: about 0.58 bar absolute, which is about −0.43 bar gauge. So in normal running the low-side gauge reads “vacuum”. If the low side leaks while the fridge is running, refrigerant doesn't spray out; instead, air and water vapour are sucked in. Once the fridge has been off a while and the two sides have equalised (about 3⁠–⁠4 bar absolute at room temperature), the pressure is above atmospheric and the refrigerant leaks out. Water vapour that gets sucked in freezes at the capillary outlet, so the fridge keeps going “cold for a while, not cold for a while” (an ice blockage). Frost on the filter drier or the capillary inlet means a dirt blockage. After a leak repair, always replace the filter drier and pull a full vacuum (background knowledge: Fixes doesn't do refrigerant system repairs).

6. Cold coil: soaking up heat behind the freezer

Hidden behind the freezer back panel (evaporator cover) is a cold coil (evaporator) with lots of aluminium fins. The very cold refrigerant boils into a gas inside it and soaks up the heat of the air passing over it. Having soaked up the heat, the refrigerant returns to the compressor through the suction line and goes round again.

Go deeper: Cold coil: soaking up heat behind the freezer

As long as there is still liquid in the cold coil (evaporator), the refrigerant boils at a fixed temperature, and that temperature is set entirely by the pressure. For R600a (isobutane), 0.58 bar (absolute) corresponds to about −25°C, and 0.47 bar to about −30°C. So knowing the low pressure is the same as knowing the evaporating temperature. Freezer air usually needs to be about −18°C, and the cold coil has to be about 7 to 10-plus degrees colder than that for heat to flow into it [approx.].

Most of the heat is absorbed as latent heat: each kg of R600a absorbs about 300-odd kJ as it vaporises, far more than just warming it up would. The liquid boils away as it flows through the cold coil, and by the outlet it should have only just finished evaporating; a little more heat turns it into superheated gas. Household systems have no expansion valve to control the superheat. So there is often also an accumulator at the outlet that catches any liquid not yet evaporated and keeps it from going back into the compressor.

Take off the freezer back panel (evaporator cover) and look at how the frost is spread. With the right amount of refrigerant, the whole cold coil carries an even, thin frost from inlet to outlet. If the compressor runs but only the first one or two rows of the cold coil by the inlet carry frost and the rest has none, first feel the tube below. If it sticks to your finger, check the defrost sensor (defrost thermostat): that can be repaired. If it doesn't, the refrigerant is short, the capillary tube is half blocked or the compressor is weak: all three are in the refrigerant system, which Fixes doesn't repair. No frost at all: the refrigerant has all leaked out or the capillary tube is fully blocked. With too much refrigerant, or too little heat load, frost spreads all the way out onto the suction line. Check the joints between the cold coil's aluminium tubes and the copper tubing closely for corrosion and oil stains: an oil stain is often the leak point.

7. Cold air: one fan for both compartments

Above the cold coil (evaporator) sits a fan motor. It blows cold air into the freezer and, at the same time, down the air duct inside the rear wall to the fridge compartment below. The cold air is usually shared out by the size of the ducts and the thermostat (or a mechanical damper); some models have an electronic air damper at the top of the duct [varies by model], which opens wider or closes down according to the temperature below. The fridge compartment actually has no cold coil of its own: it relies entirely on the cold air blown down from above. Press “Fridge door” to open it and look: as soon as the fridge compartment's door switch pops out, the fan motor stops at once and the light comes on, so the fan doesn't blow the cold air out.

Go deeper: Cold air: one fan for both compartments

A frost-free fridge relies on forced convection: the cold coil (evaporator) doesn't touch the food directly, and the fan motor does all the work of “carrying” the heat across. Some fan motors are AC shaded-pole motors, others 12 V DC brushless motors [varies by model]. In the usual design, the fan motor starts and stops with the compressor. After a defrost it also starts a little later, once the cold coil is cold again, so it doesn't blow warm, damp air and water droplets into the compartments [varies by model].

Why must the fan motor stop when the door opens? A spinning fan blade acts like a pump: with the door open, it pushes cold air out and draws warm, damp room air in. Air at 30°C and 80% humidity carries about 21 g of water per kg. Freezer air at −18°C can hold only about 0.8 g at most, and all the extra water turns to frost on the cold coil. On this model a single door switch in the fridge compartment controls both the fan motor and the light. With the door shut the switch is pressed in: the fan motor runs and the light is off. As soon as the fridge compartment door opens, the fan motor stops and the light comes on. A door switch rarely fails. When it does, the fridge thinks the door is open: the fan motor doesn't run, the light stays on, and the fridge compartment may not be cold at all. If the door switch sticks in the “door closed” position, the fan motor keeps blowing with the door open, and frost builds up especially fast.

A two-door fridge with the freezer on top usually shares out the cold air by the size of the air duct and the thermostat (or a mechanical damper). Some models use an electronic air damper [varies by model]: a small motor moves the damper flap, and the control board (PCB) opens it wider or closes it down according to the temperature sensor in the bottom compartment, which is most often an NTC (negative temperature coefficient) thermistor. Testing an NTC: the colder it gets, the higher its resistance. For example, on electronically controlled models the pill-shaped defrost sensor (defrost thermostat) reads about 2, 5 or 10 kΩ at room temperature (depending on the type), and normally a few dozen kΩ at most. A reading over 100 kΩ, or OL, means it is faulty. Also, on some models the “freezer” knob only adjusts the damper. Turning it to the coldest setting actually reduces the cold air reaching the bottom compartment, so check the settings before you decide anything is faulty.

8. Auto defrost: no scraping frost by hand

Water vapour in the air slowly causes frost build-up on the cold coil (evaporator). Every so often, the defrost timer (or the control board) stops the compressor and switches on the defrost heater under the cold coil to melt the frost into water. Watch the chart: until all the frost has melted, the cold coil temperature stays at about 0°C. Only then does it rise, and when the defrost sensor (defrost thermostat) senses it is warm enough, it cuts off the heater. The water leaves the drain trough through its drain outlet and runs down the drain tube to the water tray (evaporation tray) in the base, where the compressor's heat evaporates it.

Go deeper: Auto defrost: no scraping frost by hand

Frost forms by deposition: water vapour turns straight into ice crystals on a surface below 0°C, without becoming a liquid first. Frost is full of air gaps: its density is only a fraction of solid ice's, down to about a tenth, so it conducts heat far worse. Even a thin layer wraps the cold coil (evaporator) like a quilt, and a thicker one turns into a solid sheet of frost that blocks the air paths between the aluminium fins. The air returning from the bottom compartment is the dampest, so the cold coil's air-inlet side (usually the bottom) is the first to frost up thickly.

On timer models the defrost timer keeps the time: about every 8⁠–⁠10 hours of cooling [varies by model], it switches to defrost for 15⁠–⁠30 minutes. Electronically controlled models can do “adaptive defrost”. They look at how long the last defrost took to reach the termination temperature (some also count door-open time) and automatically lengthen or shorten the next interval. A 220 V main defrost heater is usually 100-odd to 400-odd Ω (for example about 400 Ω for a Samsung 230 V 130 W heater): work it out from the rating plate with R = V²/P. A low-power auxiliary heater (if fitted) is about a few kΩ. OL means it is broken. After defrosting there are a few more minutes of “drip time”. Only then does the compressor start, and the fan motor starts a little later still.

Defrost is ended by the defrost sensor (defrost thermostat), clamped on the cold coil outlet pipe. It is a bimetal type, or an NTC (negative temperature coefficient) thermistor on electronically controlled models. It closes only when cold enough (about a few degrees below zero) and opens once it warms above about +5°C [actual values vary by model]. Key point: at room temperature a bimetal defrost sensor is open anyway, so an open-circuit reading doesn't mean it's faulty; it has to be cold again for a true reading. The circuit usually also has a one-time thermal fuse as a backup; once it blows, the fridge never defrosts again. If the drain trough or drain tube freezes and blocks, the melt water flows back. It then freezes on the freezer floor or runs into the bottom compartment.

9. Common fault: top cold, bottom not cold enough

“Top cold, bottom not cold enough” is one of the symptoms customers report most often. This demo shows the most common cause: a defrost system failure. The defrost heater has broken, so the frost can't melt. It gets thicker day by day until the cold coil (evaporator) is packed in a solid sheet of frost that blocks it and the air duct (the simulator uses the company symptom name “Ice building up inside”). The freezer, right against the cold coil, is still fairly cold, but the cold air can't get down to the bottom compartment, so it slowly warms up. Pick “Top cold, bottom not cold enough” under “Symptom” to see another cause: on models with an electronic air damper [varies by model], the electronic air damper is stuck shut. Then press “Start repair” to see how the technician fixes it.

Go deeper: Common fault: top cold, bottom not cold enough

Why does the bottom compartment warm up first? It has no cold coil (evaporator) of its own and relies only on the narrow path of the air duct. Once the cold coil packs up with frost, the bottom compartment is the first place the fan motor's air can't reach. The freezer, meanwhile, sits right against the freezer back panel (evaporator cover) with the cold coil behind it, so it stays fairly cold by conduction. That is why “Top cold, bottom not cold enough” is a typical early symptom of a defrost system fault. Leave it longer, and even the freezer slowly warms up.

Triage on site in this order. ① Open both doors, press and hold the fridge compartment's door switch (as if the door were shut), and check for air in the top and the bottom compartment. If neither has air, check the fan motor. ② Air in the top but none in the bottom: take off the freezer back panel and first look at whether the cold coil is packed with frost (a solid sheet of frost); don't skip straight to measuring parts. If there is no frost packing, on models with an electronic air damper [varies by model] check whether it is stuck shut, and whether food is blocking the air duct. ③ Frost packing: measure the three parts on the spot with a multimeter: the defrost sensor (defrost thermostat), the thermal fuse and the defrost heater. Measure the defrost sensor while the cold coil is still cold: on a timer model it reads OL at room temperature, and that is normal. Whichever reads OL or abnormal is the faulty one. If all three are normal, on a timer model the defrost timer is faulty; on an electronically controlled model the control board (PCB) isn't sending the defrost command. ④ No frost packing, and air in both compartments but not cold enough: turn to the compressor-ageing or refrigerant-leak route, which is the refrigerant system and can't be repaired. Don't start by listening to the compressor: many fridges have to be pulled out before you can hear it properly. Feeling both side panels helps along the way: if the compressor is running but the side panels aren't warm, most often the refrigerant isn't flowing.

To confirm: take off the freezer back panel, and if you see frost packing, measure the three parts on the spot. When a customer says the fridge was cold again for a few days after a defrost and then stopped cooling, that is a common course for a defrost system fault. But a compressor problem can also cool again for a short while, so always confirm by measuring the parts on site. Cooling again for a short while doesn't mean it is fixed. On a timer model, turn the defrost timer to the defrost position to test a defrost on the spot. Some electronically controlled models (for example Samsung models with a display and buttons) have a service test mode that can force a defrost [varies by model]. To compare other causes, pick “Whole fridge not cold enough” in the “Fault simulator”, then under “Cause” pick “Refrigerant leak” or “Faulty fan motor”. With a faulty fan motor, you can't hear air moving in the freezer, and both compartments slowly warm up together. With a refrigerant leak, the compressor keeps running, but the cold coil has no frost at all. Pick “Faulty fan motor” and press “Start repair” to see how the technician replaces it.

10. From symptom to part

On a call-out, the technician starts from the symptom to find the part. In the “Fault simulator”, pick a symptom customers often report: the 3D model acts it out and lights up the parts involved. Then press “Start repair” to see how the technician fixes it. This demo shows “Leaking inside”: the drain tube has frozen and blocked, so the defrost water can't flow down to the water tray (evaporation tray). It flows back into the bottom compartment and pools under the crisper drawer. The root cause is most often a defrost that isn't hot enough (an ageing defrost heater). So after melting the ice, the technician fits a new defrost heater and at the same time adds a copper heat-conducting wire: one end wraps 3 to 4 turns round the heater, and the other runs into the drain outlet, coiled above it, so the drain outlet stops freezing. The defrost sensor (defrost thermostat) is replaced only if it measures faulty. If you only clear the tube, it blocks again after a while.

Go deeper: From symptom to part

The symptoms customers report mostly fall into a few groups: not cold enough, too cold, ice building up inside, leaking, noisy and tripping the breaker. Behind each group can be any one system: cooling, airflow, defrost, drain or controls. So, just as with the washing machine, follow the order: Look → Isolate the system → Cheap and easy first → Confirm, then replace. First ask exactly which compartment isn't cold, when it started, whether the fridge has been moved or had a power cut, whether the doors close tightly and how much is packed inside. A fridge reacts slowly: one compartment can take a whole day to go from cold to warm. So don't just open the door, feel inside and jump to a conclusion; look at several things before you judge.

You isolate the system with a few observations, in this order. Open both doors, press and hold the fridge compartment's door switch and check for air in the top and the bottom compartment (airflow system). Take off the freezer back panel (evaporator cover) and look at the frost on the cold coil (evaporator). Frost packing (a solid sheet of frost) most often points to the defrost system, so measure the three parts: the defrost sensor (defrost thermostat), the thermal fuse and the defrost heater. Frost on only the first one or two rows by the inlet: feel the tube below. If it sticks to your finger, check the defrost sensor; if it doesn't, it is the refrigerant system. No frost at all most often means a refrigerant leak or a fully blocked capillary tube (cooling system). Only then check whether the compressor is running and whether both side panels are warm. Water pooling in the bottom of the cabinet, or a drain tube that isn't clear, points to the drain system. A symptom name doesn't tell you the part. “Top cold, bottom not cold enough” can be the defrost heater, the defrost sensor, the defrost timer, the electronic air damper (only some models have one), the fan motor or even the refrigerant. “Leaking inside” is most often a drain tube blocked with ice. The root cause is most often an ageing defrost heater, so each defrost doesn't melt all the frost. If you only clear the tube, it will block again after a while, so the technician replaces the defrost heater and adds a copper heat-conducting wire at the same time. “Noisy when running” can be the fan blade scraping built-up frost (a defrost system fault: measure the three parts, then listen to the fan motor itself). It can also be the compressor's rubber mounts shifting or ageing, and that can be fixed. Leaking outside the cabinet (under the fridge) may be a cracked water tray (evaporation tray) at the back, which can't be repaired, or a drain tube that has come off or blocked, which can be fixed.

Start with what is cheap and easy. First check the settings, the door gaskets, whether the fridge stands where air can get round it and whether anything blocks the air outlets. Next, do the jobs that need no new parts (melting the ice, clearing the drain tube). Only then switch off the power and test parts: the defrost heater, the defrost sensor, the thermal fuse and the start relay (PTC). Then see whether the defrost timer or control board (PCB) is sending power. If the wiring inside has ever caught fire or melted, stop the power at once: the fridge can't be repaired. The refrigerant system (compressor, refrigerant leak, blocked copper tubing) comes last. Opening it needs brazing, a vacuum and a refrigerant charge weighed to the rating plate, and Fixes doesn't do this or recommend it. Once evidence confirms the fault (for example the frost pattern on the cold coil, a compressor that runs non-stop, side panels that aren't warm), the technician issues a not-repairable report and recommends a new fridge. After the repair, wait a few hours: the job is done only when both compartments hold normal temperatures and one defrost has run normally.