Windows > Instructions for Use and Maintenance

Instructions for Use and Maintenance

Instructions for use, cleaning and maintenance of windows and doors

Installation (assembly)

MIK windows are carefully designed and installed with precision and a high degree of professionalism. All PVC elements have factory-made mounting holes enabling the windows to be attached to the wall. In addition, the entire circumference of the window must be sealed using polyurethane foam which serves as a layer of thermal insulation between the element and the wall.

If there are any bricklaying or finishing services to be done after the windows are installed, all visible parts of the fittings, the glass pane, the frame, the casement and the handles must be suitably protected against damage and dust. Due to shavings or iron parts which can occur during installation or other craft work undertaken at the site, rust stains can develop on the lower part of the frame; these stains are not subject to complaints.

After the final installation of PVC elements (especially in new buildings) or various carcass work tasks, the installer must pay special attention to clean the insides of the frames using a vacuum cleaner with a conical attachment and a damp cloth.

After the installation of PVC builders’ joinery, the installer must remove the protective foil from the profiles. At the explicit request of the customer, the installer may leave the foil on PVC elements, leaving the customer to remove it themselves later.

Please note that the protective foil must be removed no later than three months after the installation date. Otherwise, it will be more difficult to remove the foil and we shall not be held liable for any glue residue on the profiles! The profile protective foil does not protect the builders’ joinery from any damage caused by other contractors on site.

Protecting elements is the responsibility of other individual contractors. Any physical damage occurring after the installation of the PVC builders’ joinery is not subject to complaints.

Handling windows and doors

Make sure that the opening/closing handle is always in the vertical upright position, vertical downright position or in the horizontal position.

Any other positions may cause faulty operation and damage the fittings (with the exception of multistage fittings).

Fitting maintenance

Under normal conditions, grease movable parts of the fittings once per year using suitable lubricants. You can buy maintenance kits at MIK. If the fittings are not moving well, they have to be greased earlier. In extreme conditions, such as a high degree of humidity (bathroom or kitchen) and/or a lot of dirt (industrial use, dust, etc.), movable parts of the fittings must be examined and greased once every six months or more often.

Closing and half-closing windows

You can set up the opening of the fittings, i.e. the sealing intensity. You can take care of less complicated settings yourself using an Allen key. If you need to set up more complex settings, call our experts who will be happy to do their job in a professional manner. We will be able to assess what needs to be done.

Whatever you do, do not put anything (e.g. a piece of wood, paper, etc.) between the window frame and the casement in order to prevent the window from closing. This may cause operating malfunctions or window damage, particularly when it comes to individual parts of fittings.


We would be happy to assist you in maintaining your windows. In case of any blockage, please let us know about it as soon as possible in order to prevent any significant damage and so that we can execute the necessary maintenance and setup.

Cleaning the frames

You can simply remove the usual dirt from window frames using lukewarm water with some mild dishwashing liquid or windscreen detergent. Under no circumstances, should you use scrubbing detergents, dry dust cloths and similar coarse brushes which could damage the surface treatment of the profiles.

You can clean dirty frames without any particular effort using a special cleaning detergent (COSMOFEN) which you can also buy from our company.


Seals passing through the perimeter of the window casement and door frame require regular cleaning and removal of dust and other dirt.

If you accidentally pulled the seal out of the groove, you can reinstall it by pushing the seal with your thumb into the groove next to the part where the seal is still “attached”. Do not use any tapered objects in order not to damage the seal. Before winter, we recommend that you grease the rubber portions using glycerin.

Strictly prohibited

Under no circumstances should you use cleaning and polishing agents containing solvents, as they may damage the surface layer of the PVC.

In particular, the warning applies to nail polish remover and paint diluter, as well as to all non-professional plastic cleaning detergents.


Unlike when looking through older single panes of glass, the view through modern insulating glass is clear and undistorted, which can be attributed to the extremely smooth surface of the glass. Under special lighting (under particular angles of incidence) illuminated by sunbeams, you might see rainbows (the interference phenomenon) on parallel and straight windowpanes.

This physical phenomenon is not a flaw in terms of quality, which is why it is also not subject to complaints. The insulating glass is made of two or more glass panes. Dry air or a special gas is trapped between the two glass panes. At the edge, insulating glass is sealed using a special sealant and spacer (putty) in order to prevent water and moisture from penetrating the space between two glass panes.

The large insulation capacity of the glass is due to the low degree of heat conductivity of air or gas in the space between two glass panes, as well as the additional insulating layer.

At higher temperature differences and larger dimensions of glass panels with sash bars, the sash bars might turn inwards or outwards. Spacers are not used in case of sash bar installation, especially when it comes to gas-filled spaces between glass panes.

Cleaning glass

Glass, which is part of the facade, is exposed to natural dirt and dirt produced during the construction process. If you regularly remove naturally-occurring dirt using the usual cleaning methods, this presents no issue for glass. Due to the time, location, climate and construction situation, stronger chemical and physical accumulation of dirt on the glass may occur. In such cases, cleaning must be carried out professionally and on time.

In order to prevent or at least reduce the amount of dirt during the life cycle of glass, these written instructions explain the professional and time-appropriate method of cleaning various types of glass. During the construction work, we must prevent the installed glass panes to come into contact with any aggressive dirt. If this occurs, the dirt must be disposed of immediately after it occurs using a non-aggressive agent. Concrete or cement mud, plaster and mortar are especially dangerous.

All of these components are highly alkaline and can cause the glass to corrode. If they are not removed immediately using a large amount of water, the glass may lose its shine and transparency. Powder and fine-grained residues should be removed professionally from the glass. Under no circumstances should a dry removal process be used.

Special attention must be paid to the execution of individual craft activities, especially the activities which will take place on the building after the glazing process has been completed. The formation of dirt may be minimized if individual phases of work are properly planned or if, where appropriate, protective measures are required (for example, the installation of protective foils in front of the window or facade surfaces).
The so-called first cleaning of the facility is intended to remove impurities, the formation of which is directly related to the execution of works, and not to remove all dirt accumulated during the entire construction process.

In order for the glass to retain its properties throughout its service life, it must be cleaned regularly in an appropriate manner and at appropriate intervals.

The cleaning instructions below apply to all types of glass that are installed in buildings. Large quantities of preferably clean water should always be used when cleaning the glass. In this way, you will prevent solid particles of dirt from scratching the glass surfaces.

Soft and clean sponges, cloths made of leather or artificial material, or water removal tools (squeegees) can be used as hand tools. For more efficient cleaning, you can add neutral cleaning agents or ordinary household-grade glass cleaners to water. In order to remove grease, use solvents such as spirit or isopropyl alcohol. Otherwise, it is essentially necessary to avoid the chemical cleaning agents containing alkaline lye, acids or elements associated with fluorine.

Using tapered or sharp metal tools (knives, razor blades) may cause scratches on glass surfaces. If, during cleaning, it becomes obvious that the procedure caused damage to the glass, you must immediately stop the procedure and discuss the matter with the glass supplier. Glass panes which have undergone special processing or have a functional coating on their outer surface are a high-quality product which requires special care and caution during cleaning.

Damage caused by cleaning is particularly noticeable on such glass, and their functionality can also be reduced. When using portable polishing machines to remove damages on glass surfaces, you must remember that a lot of glass material is removed by polishing. This may cause optical distortion (also known as the “lens effect”). It is prohibited to use them on processed glass or coated glass.

Subsequent polishing of tempered glass can lead to a reduction in its strength, which may reduce the safety of the construction element.

Condensation water

Under certain climatic conditions, “perspiration” (the accumulation of condensation water) can occur on the glass pane, the frame or other construction elements.

Let us look at two examples from everyday life. Take a bottle out of the refrigerator and place it on the table. You will see that the bottle will fog up in a short time. Your glasses fog up immediately after you walk into a heated room from the outside. This is due to the fact that warm air can take on significantly more moisture than cold air.

As hot air meets a cold surface, the air cools down and the amount of moisture that is not acceptable at low temperature is eliminated. You can see it as condensation humidity/water.

This phenomenon is particularly pronounced when high humidity in the air meets low outside temperatures. High amount of humidity is present in the bathroom, kitchen etc. The prerequisite preventing this phenomenon from occurring is proper ventilation.

Proper ventilation

The joints on your new MIK windows are sealed much better than the windows that you have been used to before. Because of this, your rooms are no longer permanently ventilated in an uncontrolled manner through non-sealed spaces in windows and doors. Now you can ventilate them according to your needs and tastes. The sweat which is more or less constantly eliminated by our bodies, moisture in the air that we breathe out, steam generated by cooking and washing, etc.: all these phenomena have a negative influence on the degree of relative humidity in our home. A person eliminates anywhere from 1 to 2 liters of water during sleep alone.

Regular ventilation of our rooms prevents a high degree of moisture and mold formation. This also increases the service life of paints, wallpapers, coatings, paneling, floors and furniture. Ventilate for a short period of time, but intensively, preferably by opening two opposite windows (doors) as widely as possible, thus creating a draft. Approximately 5 minutes of such ventilation will suffice (naturally, this also depends on outdoor temperature).

You can easily control the duration of ventilation during the cold winter months. If you open the window, the cold outer glass will fog up immediately. As soon as the fog disappears and the surface of the glass is dry again, close the window. 

In the meantime, the spent air was replaced with fresh air, while the walls and the furniture have not cooled down yet. Excessive ventilation is irrational, as it unnecessarily cools walls and furniture.

Ventilate the rooms 2 to 3 times per day, according to their use. While the windows are fully open, turn off the heating and turn it back on after ventilation. Efficient ventilation cannot be provided if the window casements are constantly open or even tilted. Ventilation must be exclusively carried out using air from the outside since cold air can only accept very little water.

Never evacuate damp air out of the room into other rooms – always evacuate it directly out of the building! After you open the windows, fresh air is heated in a few minutes due to the heat accumulated in the walls of the building. A fogged window is a sign that you must ventilate the room since the air in the room with a fogged window is too humid. At the same time, ventilation also ensures a pleasant and leveled climate in the apartment.

Exterior dew – condensate on the outside of the window

Dew on the outside window glass can occur occasionally, especially when humidity is elevated in the morning. This phenomenon is not a fault in production or a disadvantage, but a proof of the high heat protection of glass, as well as of a good quality. The insulation between the external and the internal glass pane functions, the heat remains in the room, and the external glass pane remains cold.

This provides basic conditions for dew forming from time to time. Especially in areas with increased air humidity, the air can heat up faster than glass in windows in the morning. This results in condensation on the external glass. Basically, this is the same thing as dew forming on grass.

Wettability of glass surfaces

The wettability of glass surfaces is not always the same. The contact of manufacturing rollers, fingers, patterned paper, vacuum grippers, labels, sealant residue, silicone components, lubricants or environmental influences can cause small changes in the structure of the glass surface.

When the glass pane is wet due to condensation, rain or cleaning, light refracts differently on such surfaces, and prints are visible. When the glass pane dries, these prints disappear.

Thermal break

When the temperature increases by 50°C, a 1m long glass pane extends by approximately 0.5mm. This so-called thermal expansion is not a dangerous phenomenon if the glass pane is heated evenly over the entire surface. However, if the glass pane is not evenly heated, certain areas of the glass pane stretch more and others less.

This results in tensions in glass. These thermal tensions are higher if the temperature difference in the glass is higher as well. Often, a part of the glass pane is exposed to strong sunlight, while the other part of the glass pane is in the shade.

Such “partially shaded” glass panes will, in any case, warm up unevenly. Ordinary transparent “float glass” can transfer or resist a temperature difference of about 40°C.

If uneven heating of glass results in a higher temperature difference, the glass can break. Such a refraction is not subject to complaints.

Instructions for installing ALU sills

When installing outer ALU sills, it is important not to squeeze the end profiles of ALU sills right into the sill. The customers must inform the plasterer of it if they are laying insulation around a sill that has already been installed by us, or if the plasterer is installing the ALU sills as they make the facade.

If the end profiles are squeezed right into the sill, the sill may strain, which is not a sign of a faulty installation but rather a subsequent error provoked by the plasterer. In the event of high temperatures, the sill will namely withdraw from the parapet. The extension of a one-meter-long ALU sill at 50°C amounts to about 2mm. The end profile of the ALU sill itself can be covered by max 5mm or half of the width of the end profile.

The plasterer must pay attention that the insulation does not put pressure on the sill. This can result in the sill lifting, resulting in loss of drop, which can provoke water retention on the sill and, consequently, water damage. The drop of the outer sill is supposed to amount to 6°. We suggest that the customer informs the plasterer of the execution of a durable elastic joint between the sill and the facade, which ensures waterproofing.

It is also important to warn the plasterer to protect the sill before making the facade. Facade emulsion is a very aggressive substance; with ALU sills, paint can peel off, which is not subject to complaints. When installing stone sills or artificial stone sills, contact with the emulsion may result in the matting effect of the sill surface, which is also not subject to complaints. It is also necessary to protect the sills against falling building materials (facade glue, plaster, finishing layer, etc.). Cleaning of dried materials can cause damage to the sills.

The masking tape used as an installation protection is only intended as short-term protection of elements. Prolonged exposure to atmospheric agents may cause the paint to peel off upon removal. For cleaning painted elements, we recommend non-aggressive cleaning agents which do not contain any ingredients (acids) that could influence the varnish or make it peel off the foundation. Such damage is not subject to complaints.

Detail of the ALU sill

Cross-section of the sill

Instructions for installing external Venetian blinds

In order to guarantee timely and high-quality installation, you can find information regarding the process of external Venetian blinds installation in the annex below:

  • the installation of console brackets and masks prior to the installation of the facade on the building must be executed at the same time as the installation of PVC elements (Phase 1),
  • external Venetian blinds can be measured before the finishing facade layer or after the facade is finished, according to the customer’s preference (Phase 2),
  • production of Venetian blinds in the manufacturing department: the deadline for standard program products is about two to three weeks after the measurement has been executed (Phase 3),
  • the installation of Venetian blinds at the location of the customer: upon agreement with the customer (Phase 4).

We kindly ask you to inform us in a timely manner about the condition of your building or the possibility of further work so that we can stick to the agreed deadlines. When sealing the facade or making plaster, the maximum overlap of the PVC elements must be taken into consideration in case of subsequent installation of external Venetian blinds, whereby said overlap must in no event exceed 5mm.

Otherwise, installation of external Venetian blinds will not be possible as the hand lever would either be too close to the casement or on the casement itself. When gluing the facade over the concealed mask, care should be taken to ensure that there is a distance of 120mm between the front side of the mask and the window frame, so that the slats do not stick to the mask after their installation.

Detail of the facade being made close to the window frame

Facade over the concealed mask

Instructions for connecting electrical devices

Electrical connection of the roller shutter to the switch

  • A switch enabling the simultaneous operation of the UP and DOWN command must not be installed in order to operate the drive.
  • More than one drive cannot be installed on one switch.
  • In the event of a different connection, use the supplied original manufacturer’s instructions. The instructions are attached according to the built-in system.
  • We recommend the use of 1.5mm2 feeder cables.
  • The integrated shutter drive cable must be routed to the junction box using a hose in case of a possible drive replacement.

Electrical connection of the roller shutter to the remote receiver

  • Remote receiver-operated roller shutters can only be operated using the original remote control.
  • In the event of a different connection, use the supplied original manufacturer’s instructions.
  • We recommend the use of 1.5mm2 feeder cables.
  • The integrated shutter drive cable must be routed to the junction box using a hose in case of a possible drive replacement.

Connecting the front door electric strike

In the event of a different combination of electric strike use, you must consider and follow the original manufacturer’s instructions.

The MIKrovent 100 electrical connection

The MIKrovent 100 is connected to the 230V/50Hz network using the instructions provided for the cable attached to the device.

The MIK d.o.o. installers do not execute the operations of providing the electrical connection to the network. Such connection must be carried out by a qualified electrician. The installation and connection must be executed with the electrical voltage turned off.
MIK d.o.o. shall not be held responsible for any faulty electrical connections executed in the building. Damaged electrical elements are not subject to complaints.

Instructions for connecting external Venetian blinds

  • After installation, the mains plug (connector) on the Venetian blind must remain accessible.
  • A switch enabling the simultaneous operation of the UP and DOWN command must not be installed in order to operate the drive.
  • In the event of a different connection, use the supplied original manufacturer’s instructions. The instructions are attached according to the built-in system.
  • The remote control interface can only be used with the original remote control.
  • The combination of a remote control and wall switch is not a possibility.


It is not permitted to perform a parallel connection of two or more drives to one single-pole switch. In the event of a reverse voltage of the condenser, there is consequently a large possibility that parallel connected drives will blow out.

When two motors are parallel connected, a two-pole switch or a suitable decoupling relay must be used.

Windows > Instructions for Use and Maintenance