The situation when the refrigerator stops maintaining the temperature, and the compressor works without interruption, often confuses the owner. Visually, the unit may look serviceable, but the heat reigns inside, and the food begins to deteriorate. One of the hidden but critical reasons for this behavior is the destruction or wetting of the thermal insulation layer. Replacing insulation is a complex process that requires an understanding of the design of the device and compliance with safety precautions. Unlike replacing a seal or a lamp, here we are talking about intervention in the housing, which was created at the factory as a single monolith. However, if you are faced with mechanical damage to the walls or serious dampness of the insulation, restoration is possible. thermal insulation layer.
Replacing insulation is a complex process that requires an understanding of the design of the device and compliance with safety precautions. Unlike replacing a seal or a lamp, here we are talking about intervention in the housing, which was created at the factory as a single monolith. However, if you are faced with mechanical damage to the walls or serious dampness of the insulation, restoration is possible.
Before starting dismantling, you need to clearly understand the scale of the work. You have to not only remove the old material, but also ensure the tightness of the new layer to avoid the formation of condensation and mold in the future. Complete replacement of polyurethane foam insulation at home is almost impossible without special equipment for foaming, so most often we are talking about local repairs or replacement of slab materials.
Diagnostics of the condition thermal insulation
The first step is always an accurate diagnosis. Do not rush to disassemble a working refrigerator if the problem lies in another unit. Check the operation of the thermostat, the condition of the rubber seals and the cleanliness of the condenser. If you are sure that heat escapes through the walls, look for indirect signs of damage to the insulation.
Often, wetting of the insulation is visible to the naked eye. Yellowish spots, plastic blisters, or even drops of water (“crying” walls) may appear on the inner or outer wall. In places where the insulation is damaged, the housing may be warmer to the touch than in other areas, or, conversely, freeze through, forming frost on the outside.
- 🔍 Visual inspection of the housing for dents, cracks and swelling of the plastic.
- 💧 Checking the internal walls for the presence of condensation or ice crusts in unexpected places.
- 🌡️ Measurement of the wall surface temperature with a thermal imager or tactilely (comparison with the norm).
- 👂 Analysis of the compressor operation: continuous operation without rest cycles indicates a loss of cold.
If you find that the thermal insulation is damaged as a result of an impact or hole, take action needed immediately. Moisture that gets inside polyurethane foam (PPU)sharply reduces its properties and causes corrosion of the metal case from the inside. Ignoring the problem will lead to complete failure of the equipment.
⚠️ Attention: If the refrigerator continues to work, but you notice signs of wet insulation, immediately disconnect it from the network. A humid environment inside the case creates a risk of short circuit and electric shock.
Selection of materials for restoring insulation
Factory thermal insulation of refrigerators is most often made of polyurethane foam. This material has excellent properties, but replacing it in domestic conditions requires the use of two-component polyurethane foam with a low coefficient of expansion. Conventional construction foam will not work here, as it can expand too much and deform the thin walls of the chamber.
Tile insulation can serve as an alternative for local repairs or filling voids. Penoplex or Technoplex (extruded polystyrene foam) have a high density and low thermal conductivity. They are easy to process and do not absorb moisture, which is critically important for refrigeration equipment.
When choosing a material, focus on the following parameters:
- 📉 Thermal conductivity coefficient (the lower, the better).
- 🛡️ Moisture resistance and vapor permeability (should be minimal).
- 🔥 Fire resistance class (preferably self-extinguishing materials).
- 🏷️ Food safety (no toxic emissions).
You will also need auxiliary materials: aluminum tape for sealing joints, adhesive foam for fixing slabs and sealant for processing seams. Do not use bitumen-based materials or with a strong odor, which can be absorbed into the plastic parts of the camera.
Preparation of tools and workplace
High-quality repairs are impossible without proper preparation. You will need to assemble a set of tools that will allow you to carefully dismantle the body elements and clean the surfaces. It is better to carry out work in a well-ventilated area or outdoors, since old materials and chemical components of foam can emit volatile substances.
The main list of tools includes a screwdriver with a set of bits, a sharp construction knife, spatulas and protective equipment. Do not forget that working with insulation requires protection of the skin and respiratory tract. Fine dust from old foam or foam vapor can cause an allergic reaction.
☑️ Preparation for replacing insulation
Pay special attention to organizing the space. The refrigerator must be defrosted and completely dry. Prepare containers for collecting waste in advance, since there can be a lot of old insulation, and it tends to crumble and fly apart.
Technology for dismantling old insulation
The process of removing old material depends on the design of your model. In most modern refrigerators, access to the insulation is hidden behind decorative panels, which can be glued or secured with latches. You must act extremely carefully so as not to damage the plastic of the inner chamber, which is very fragile at low temperatures and aging.
If it is necessary to remove damaged PU foam, it is cut out mechanically. Use a knife or chisel to carefully remove the material, being careful not to damage the evaporator (refrigerant tubes), which are often embedded in or attached to the wall. Damage to the cooling circuit will lead to expensive repairs with refilling with freon.
Main stages of dismantling:
- Removing the rear metal panel of the refrigerator (access to the compressor compartment).
- Removing the plastic linings inside the chamber (if the design allows).
- Carefully cutting or picking out the old insulation.
- Thorough cleaning and degreasing of surfaces.
⚠️ Attention: When working with old polyurethane foam, use a respirator. Dust from the destroyed polymer can be toxic and cause respiratory irritation.
After removing the main body of insulation, the chamber must be allowed to dry. If there was a lot of moisture inside, the drying process may take up to 24 hours. You can use a hairdryer in cold air mode to speed up the process, but do not heat the plastic parts.
Installation of new thermal insulation
Installation technology depends on the selected material. If you use tile insulation (penoplex), it must be cut to the size of the cavity with a small margin. The sheets are stacked tightly, without gaps. All joints between the sheets and the walls of the chamber must be glued with aluminum tape or filled with polyurethane foam.
When using two-component foam to fill voids, it is important to follow the dosage. The foam is applied in layers. The first coat must be completely dry before applying the second to avoid excessive pressure on the walls. Fill the space gradually, controlling the expansion process.
Comparison of restoration methods:
| Parameter | Plate material (Penoplex) | Mounting foam (PPU) | Mineral cotton wool |
|---|---|---|---|
| Thermal insulation | High | Very high | Average |
| Moisture resistance | Absolute | High | Low (requires vapor barrier) |
| Installation complexity | Low | High | Average |
| Hull risk | Minimal | Average (spread) | Minimum |
After laying the material and fixing all the elements, it is necessary to give the structure time to polymerize and fix. Only after this can you begin assembling the decorative panels and back cover.
Nuances of working with foam
Never fill the cavity volume by more than 30-40% at one time. The foam expands 2-3 times, and excess pressure can tear the inner plastic tab from the metal body, which will lead to irreversible deformation of the chamber.
Assembly and initial launch
The final stage is assembling the refrigerator. Make sure that all wires, if affected, are securely insulated and laid in their proper places. Decorative panels should fit without gaps or squeaks. The rear cover of the compressor compartment must be tightly closed to ensure proper airflow.
The first start-up after thermal insulation repair requires monitoring. Plug in the refrigerator without loading food. Let it run a full cycle before turning off the compressor. Check the temperature inside the chamber and make sure that there is no condensation on the walls.
Pay attention to the following points:
- ❄️ Uniform cooling throughout the entire volume of the chamber.
- 🔇 No extraneous noise or vibrations.
- 🌡️ Temperature of the case outside (should not be hot in places of insulation).
If there are no complaints within 24 hours of operation, you can gradually load the products. However, full refrigeration mode will be established after 2-3 days of operation.
Can I use regular polyurethane foam from a balloon?
Use regular foam household foam is highly not recommended. It has a high coefficient of secondary expansion, which can deform the internal chamber of the refrigerator. In addition, household foam is often more fragile and retains heat less well compared to professional two-component compositions.
What to do if the evaporator tube is damaged when replacing the insulation?
If you hear a hissing sound or see oil coming out of the tube, it means the circuit is depressurized. It is necessary to immediately stop work, ventilate the room and call a specialist for soldering and refilling with freon. It is impossible to fix this on your own without equipment.
How long does the new insulation take to dry before turning it on?
Drying time depends on the type of material. Polyurethane foam requires from 2 to 12 hours to completely polymerize. Board materials do not need drying time, but it is recommended to wait at least 1 hour after assembly so that possible odors from glue or sealant evaporate.
Do you need to remove the door when replacing insulation?
In most cases, removing the door is not necessary if access to the damaged area is through the back panel or bottom. However, if the damage is in the upper part of the chamber or in the door itself, dismantling the door leaf is required for high-quality work.