Making the water supply to a private home or cottage constant and uninterrupted is not an easy task. The most difficult thing is to ensure water supply in winter. To prevent pipes from freezing, they can be laid below the freezing depth, but weak points still remain. The first is abnormally cold winters, which periodically break all records. The second is the entry points into the house. They freeze often anyway. The solution is to install a heating cable for the water supply. In this case, sewerage is desirable, but it can be buried shallowly. And in the areas leading into the house, you can install a more powerful heater and better insulate it.
Types of heating cables for water supply
There are two types of heating cables - resistive and self-regulating. Resistive ones use the property of metals when passing through electric current heat. In this type of heating cables, a metal conductor is heated. Their characteristic feature is that they always emit the same amount of heat. It doesn’t matter whether it’s +3°C or -20°C outside, they will heat up the same way - at full power, therefore, they will consume the same amount of electricity. To reduce costs in relatively warm times, temperature sensors and a thermostat are installed in the system (the same as those used for electric heated floors).
When laid, resistive heating wires should not intersect or be located next to each other (close to each other). In this case, they overheat and quickly fail. Pay close attention to this point during the installation process.
It is also worth saying that resistive heating cables for water supply (and not only) can be single-core or double-core. Two-core ones are more often used, although they are more expensive. The difference is in the connection: for single-core ones, both ends must be connected to the mains, which is not always convenient. The two-core ones have a plug at one end, and at the other end there is a fixed ordinary electrical cord with a plug, which is connected to a 220 V network. What else do you need to know? Resistive conductors cannot be cut - they will not work. If you bought a coil with a section longer than necessary, lay it in its entirety.
Self-regulating cables are made of a metal-polymer matrix. In this system, the wires only conduct current, and the polymer, which is located between the two conductors, heats up. This polymer has an interesting property - the higher its temperature, the less heat it releases, and vice versa, as it cools down, it begins to release more heat. These changes occur regardless of the condition of adjacent sections of the cable. So it turns out that it regulates its own temperature, which is why it is called self-regulating.
Self-regulating (self-heating) cables have many advantages:
- they can intersect and will not burn out;
- they can be cut (there are markings with cutting lines), but then you need to make an end coupling.
They have one drawback - the high price, but the service life (subject to the operating rules) is about 10 years. So these expenses are reasonable.
When using a heating cable for any type of water supply system, it is advisable to insulate the pipeline. Otherwise, heating will require too much power, which means high costs, and it’s not a fact that heating will cope with particularly severe frosts.
Installation methods
The heating cable for water supply is laid outside or inside the pipe. For each method there are special types of wires - some only for external installation, others for internal installation. The installation method must be specified in the technical specifications.
Inside the pipe
To install the heating element inside water pipe, it must meet several requirements:
- the shell should not emit harmful substances;
- degree electrical protection must be at least IP68;
- sealed end coupling.
To be able to thread the wire inside, a tee is placed at the end of the pipeline, into one of the branches of which the wire is inserted through the gland (included in the kit).
Please note that the coupling - the transition point between the heating cable and the electrical cable - must be located outside the pipe and gland. It is not intended for wet environments.
A tee for installing a heating cable inside a pipe can have different outlet angles - 180°, 90°, 120°. With this installation method, the wire is not fixed in any way. It is simply tucked inside.
Outdoor installation
The heating cable for the water supply must be secured to the outer surface of the pipe so that it fits tightly over the entire area. Before installation on metal pipes, they are cleaned of dust, dirt, rust, welding marks, etc. There should not be any elements left on the surface that could damage the conductor. A rein is placed on clean metal and fixed every 30 cm (usually possible, less often not) using metallized adhesive tape or plastic clamps.
If there are one or two threads stretching along, then they are mounted from below - in the coldest zone, laid parallel, at some distance from each other. When laying three or more wires, they are positioned so that they most of was located below, but the distance between the heating cables is maintained (this is especially important for resistive modifications).
There is a second installation method - a spiral. The wire must be laid carefully - they do not like sharp or repeated bends. There are two ways. The first is to unwind the coupling, gradually winding the freed cable onto the pipe. The second is to secure it with slack (bottom picture in the photo), which is then wound and secured with metallized adhesive tape.
If a plastic water pipe is to be heated, then metallized tape is first glued under the wire. It improves thermal conductivity, increasing heating efficiency. Another nuance of installing a heating cable on a water supply system: tees, valves and other similar devices require more heat. When laying, make several loops on each fitting. Just watch out for the minimum bend radius.
How to insulate
It is definitely not advisable to use for insulation of a heated pipeline. mineral wool of any origin. She is afraid of getting wet - when wet, she loses her thermal insulation properties. Having frozen wet, after the temperature rises, it simply crumbles into dust. It is very difficult to ensure the absence of moisture around the pipeline, so it is better not to use this insulation.
Insulation materials that compress under the influence of gravity are not very good. Having shrunk, they also lose their thermal insulation properties. If your pipeline is laid in a specially constructed sewer system, nothing can put pressure on it, you can also use foam rubber. But if you are simply burying the pipe, you need rigid thermal insulation. There is another option - put a rigid pipe, for example, a plastic sewer pipe, on top of the crushable insulation (for example, closed-cell polyethylene foam).
Another material is polystyrene foam, molded in the form of pipe fragments different diameters. This type of insulation is often called shell insulation. It has good thermal insulation characteristics, is not afraid of water, and can withstand some loads (depending on density).
What power is required for a heating cable for a water supply system?
The required power depends on the region in which you live, on how the pipeline is laid, on the diameter of the pipes, whether it is insulated or not, and even on how exactly you lay the heating - inside the pipe or on top of it. In principle, each manufacturer has tables that determine cable consumption per meter of pipe. These tables are compiled for each power, so there is no point in posting any of them here.
From experience, we can say that with average insulation of the pipeline (expanded polystyrene shell 30 mm thick) Middle lane In Russia, a power of 10 W/m is enough to heat one meter of pipe from the inside, and at least 17 W/m must be taken from the outside. The further north you live, the more power (or thicker insulation) you need.
With or without thermostat?
If you want to pay a pittance for heating the water supply, it is better to install a thermostat. Even if you are planning to install a self-regulating heating cable. Basically, the characteristics are as follows: switches on at +3°C, switches off at +13°C.
If your water is supplied from a well, it will never have a temperature of +13°C. It turns out that the heating will work all the time, even in spring and summer. In the summer, of course, the cable can be turned off, but in the spring and autumn this cannot be done due to the possibility of sudden frost. It’s somewhat simpler, but not much - in summer the water there can have a temperature just above the shutdown threshold. But this is in the summer, and during the hottest period. And in general, why do you need to heat, say, water that goes into cistern? And you will still heat the one that goes to the kitchen or shower with boilers or instantaneous water heaters.
In any case, it turns out that a thermostat is needed. On it you set the shutdown temperature to around +5°C. The costs of heating the pipeline fall significantly. At the same time, the service life of heating cables increases significantly - they have a certain service life of working hours. The less they work, the longer they will serve you.
Heating cable for water supply - connection diagram to the thermostat
When installing a water heating system with a thermostat, you will also need to install a temperature sensor. There is a difficulty here. It must be placed on the pipe so that it is not affected by the temperature from the heaters. That is, it does not need to be thermally insulated from the pipe, but it is necessary from the cables.
It is advisable to install the thermostat itself indoors. It is connected to the brownie through a circuit breaker and, preferably, an RCD. The power consumption of the heating cable is small, so the rating of the machine can be about 6A, the rating of the RCD, choose the nearest larger one, otherwise the leakage is preferably 30 mA.
Connect the heating cable for the water supply to the corresponding connectors on the thermostat body. If there are several branches, they are paralleled. A temperature sensor is connected to adjacent contacts. Each thermostat has markings that make it clear what needs to be connected and where. If there is no marking, it is better to buy another one: the performance of this copy is very doubtful.
Effective thermal insulation of an autonomous water supply system ensures that the optimum temperature is maintained and prevents freezing of the pipeline in winter. For these purposes, a special cable is provided for heating pipes, the installation of which is carried out in the cavity of the pipe or by winding along the outer surface. An easy-to-install heating cable system can provide reliable protection for a private water supply when operating in special climatic conditions.
Operating principle and advantages of the device
The heating cable operates on the principle of a heating element or a spiral element, when the electricity conducted through it is converted into heat, which ensures heating of water pipes at low temperatures.
Thermal energy is sufficient to maintain the optimal temperature inside the pipeline and prevent crystallization and freezing of the liquid.
The heater material has high hydro-, electrical insulating and strength characteristics, which eliminates the possibility of deformation, damage and melting.
Important! When choosing a device, it is worth considering that only two- and three-core wires have increased protection from electromagnetic radiation of the conductor.
The heating element for water supply has a number of advantages:
- High thermal conductivity and different lengths of products ensure effective heating of pipes when exposed to low temperatures.
- Possibility of internal and outdoor installation cable for any pipe laying - underground, street, indoors.
- Built-in protection against melting and overheating when used in extreme conditions.
- Safety and durability of the heating system.
- Availability of operating power adjustment taking into account temperature conditions.
Types of cables for heating pipes
Heating cable for pipes is available in two types: resistive and self-regulating. Each of them differs in operational features and area of use.
Resistance heater
Externally, the design is a boiler with an elongated base consisting of a heating element - a single-core or two-core wire. From the outside, the device is protected by durable and wear-resistant thermal insulation.
The resistive heater ensures fast and uniform heating in each area of the system. Ready-made devices of a certain length for pipes for sewerage, water supply and heating are available for sale. Single-core cables are intended for external installation on the surface of pipes, two-core devices are suitable for external and internal installation.
The operating principle of a heating device for water supply is determined design features products:
- IN single-core wire heating is carried out by only one core, so it is connected to the power supply at both ends.
- In a two-core wire, one conductor conducts electricity, the other conducts thermal energy, creating a closed heating system.
The main advantages of a resistive heater are affordable cost and ease of installation.
The disadvantages of a device of this type include the following:
- Uniform heating of pipes along the entire length eliminates the possibility of increased heating of individual sections of the water supply system.
- Susceptibility to deformation and overheating in places where individual elements intersect.
- Inability to change the length of the finished product.
- The inability to adjust the operating power of the device, which leads to a decrease in efficiency.
- Inability to repair or replace the damaged area. In this case, the device must be completely replaced.
Self-regulating heater
Universal type of heating device for water and sewer systems. It allows you to intensively warm up the freezing areas of the pipes, while the warm areas are not exposed to heat.
A distinctive feature of a self-regulating cable is the regulation of operating power and the rate of supply of thermal energy. When the set temperature drops, the device provides automatic heating.
A self-regulating heating cable for water supply consists of two cores, which are connected to each other by a thermoregulating matrix that controls the heating temperature conditions of the cable.
The main advantages of the device include:
- Good efficiency thanks to spot heating.
- Possibility of adjusting the required length of the product.
- The possibility of overlapping winding, which eliminates overheating of areas.
- Simple and affordable installation without the need for additional installation of temperature sensors.
Calculation of operating power of heating cables
Using a heating cable inside a pipe is rational if it is impossible to heat it from the outside. It can be used for pipes whose diameter does not exceed 3.2 cm, since the device itself has low power - from 9 to 13 W/m.
For outdoor installation, cables with a power of 17 to 32 W/m are used. If the pipeline is equipped with PVC pipes, then the permissible power should not be higher than 17 W per linear meter to avoid damage to the pipe.
Calculation of the required power of the heating device is carried out taking into account:
- Pipe diameter.
- Material for making pipes.
- Thickness of the thermal insulation layer.
- Heat losses in the pipeline.
Features of installation of cables for heating water supply
The warm cable can be installed inside water pipes or fixed outside. Each method involves the use different types heaters - some of them are intended only for indoor installation, others for outdoor installation.
Installation inside a pipe
For installation inside the pipe, a special heater is used that is resistant to humid and acidic environments. In addition, it must meet the following requirements:
- Do not release hazardous components when heated.
- Have high degree electrical protection.
- Equipped with a sealed end coupling.
The cable is inserted into the pipeline system through a special tee - coupling into one of its branches using a gland. In this case, the other end of the wire must be connected to the power supply.
Important! The tee for connecting the heating and electrical wires should be located on the outside of the pipe and the inlet gland. It can have different cable entry angles - 90, 120 and 180.
The efficiency of a heating cable for water supply is doubled when installed internally, which allows the installation of a low-power device. In addition, this installation method requires minimal thermal insulation of pipes.
External installation method
In this case, the installation of the heating cable for the water supply is carried out from the outside and requires reliable fixation over the entire area.
Before installation, the water pipe is thoroughly cleaned of contaminants. This will prevent possible damage and deformation of the conductor. Next, the prepared heater should be laid on the surface in waves with fixation every 25 cm. Adhesive tape on a metallized base or plastic clamps are used as a fixator.
When using several cables simultaneously, they must be fixed parallel to each other on the bottom side of the pipe.
Another installation method is spiral. In this case, the heating cord is wrapped around the pipe in turns in increments of 5 cm. For reliable fixation, foil tape is used, which will ensure additional protection pipes from excessive heating.
Determination of power for heating cables
This characteristic is important for the efficient operation of heating cables. It is determined taking into account the climatic conditions of the region in which the autonomous water supply is installed, the diameter of the water pipes, thermal insulation and the method of heating installation.
- If the installation and connection of the cable is carried out inside pipes, a device with a power of up to 11 W/m is suitable.
- When installing on top of a pipe, you should choose a product with a power from 17 to 55 W/m.
Powerful cables require significant energy consumption, which leads to a significant increase in system maintenance costs.
Thermostat for heating cable
The thermostat for heating cables automates the process of maintaining temperature regime, ensures a reduction in the cost of heating the pipeline system and an increase in the service life of cables.
The device is mounted in the house electrical panel with a connection via an RCD, and the temperature sensor is mounted on a pipe with preliminary thermal insulation from the heating cable.
Important! A resistive cable requires the connection of a thermostat, which will allow high-quality heating of the surface of the pipes and reduce electricity consumption. A self-regulating heater can operate without connecting a thermal relay.
If water directly enters the water supply system from a well or well, then the water supply can be heated continuously throughout the year. The exception is the summer period.
To ensure long-term operation of the water supply heating system, the following recommendations must be taken into account:
- If cables are used to warm household networks, the connection must be made through an automatic device or RCD.
- When partially laying water pipes outdoors and indoors, it is safer to install self-regulating devices.
- When wrapping cables around pipes, it is necessary to take into account the degree of possible bending of the material in order to prevent damage to the surface and difficulty in the passage of current.
- High efficiency and reduced electricity costs depend on the right choice insulating material, cable length and power.
- When installing the heater, you must follow basic fire safety rules.
Even novice craftsmen can organize high-quality and safe heating of the water supply with a heating cable. It is effective and affordable option solving the problem of freezing of water supply, sewer pipes and other systems during cold periods and under extreme operating conditions.
The conditions for laying a water main to a private house are not very favorable. More precisely, it is not always possible to lower the pipeline underground below the freezing depth, which is why the water in it turns into ice, into best case scenario blocking the flow area. At worst, the pipe material unfreezes and breaks down. To avoid such troubles, in critical areas of the water supply it is recommended to use a special heating cable powered by electricity. You will learn how to install it correctly from this article.
When do you need to heat utility networks?
Artificial heating of communications entails additional energy consumption, most often electricity. As a result, the cost of maintaining a private home in winter increases. Therefore, it is worth listing the situations when heating systems are indispensable:
- The external water supply or sewerage network must be laid in the ground above the freezing line. Reason: rock ridge, concrete structures, groundwater and other underground obstacles that prevent digging a deep trench.
- The water supply section has to be routed along the street. The most common case is cottages built on pile-screw foundation. Because they are raised above ground level, pipe insertions up to several meters in length are at risk of freezing in winter.
- At the entrance of the pipeline to a well or borehole.
The most practical way to solve the problem is to install an electric heating cable on the dangerous section of the pipe. Insulation is not a panacea, because if during severe frosts there is no flow through the main line, then an ice plug will still form inside. Reliable operation of the water supply will be ensured only by constant heating together with thermal insulation. More information about the use of cables is described in the video:
Reference. Electric heating with special conductors of various sections is also used on drains, problem areas of the roof and for protection sewer networks. Another popular application is electric heated floors.
Types of heating wires
To warm up water supply lines, 2 types of cables are used:
- Resistive. It works like a regular heater, converting electricity into heat due to the increased resistance of the internal element. Produced with 1 and 2 cores.
- Self-regulating. The principle of operation is as follows: between two current-carrying conductors there is a semiconductor matrix that changes resistance along with temperature environment. The lower it is, the lower the resistance value and the greater the heat transfer. Depending on the installation conditions, heating and power consumption may vary in individual sections of the heating circuit.
Note. The characteristics of both types of cables allow them to be used both outside and inside pipes, as will be discussed below.
The use of resistive wire is a cheaper way to warm street communications than purchasing and installing a self-regulating electrical cable. But for correct operation, it must be connected to power through a thermostat equipped with temperature sensors, upon whose command the control unit will turn off the heating when a certain temperature is reached. Resistive conductors also differ in other features:
- high heat transfer (up to 60 W/m), allowing to heat large-diameter pipelines and shut-off valves (maximum temperature - up to 70 ° C);
- the single-core version of the product must be ringed in order to connect to the power source;
- At the end of the two-core conductor you need to install a special coupling, as shown in the diagram.
Self-regulating heating cable is used to heat pipes without any additional devices and is therefore a more economical option. The surface of the product can heat up to 60 °C, and the power can vary from 9 to 50 W/m. Thanks to the flat cross-section of the cable cut, such a heater adheres better to the surface and distributes heat. Since self-heating wire costs twice as much as resistive wire, it is chosen to protect short sections or entries into the house.
Reference. Trusted manufacturers of cables of both types present on the CIS market are the brands Devi, Ensto and Raychem.
Methods for installing a heating circuit
Water heating thermal cables are installed in two ways - outside and inside the pipe, each of them has its own pros and cons. The advantages of the first option are as follows:
- the conductor does not block part of the flow section of the main line;
- This method makes it easier to heat extended areas and shut-off valves;
- there is no need to install and maintain special units for inserting the cable into the pipeline.
External electric heating requires more power from the elements. If it is customary to lay a wire with a heat transfer of 10-13 W/m from the inside, then the pipe will have to be heated from the outside with a cable with a power of 15-40 W/m, which reduces the efficiency of the system.
The second unpleasant moment is the difficulty of repairing products buried in a trench. It is possible that to determine the location of the fault, the entire highway will have to be dug up. Conversely, when repairing a break or replacing pipes, you can accidentally damage the cable heater.
Heating the pipeline from the inside is not only more economical, but also more practical from a maintenance point of view. True, to run the conductor hermetically inside, you will have to install an additional pass-through unit. Again, if the street water supply is long, you need to increase the diameter of the pipe just to successfully push the cable through. And if a valve or tap is provided on the main line, then internal installation and not at all possible.
Advice on choosing the power of a thermostatic conductor for external heating. If the pipeline diameter does not exceed 20 mm (¾“), then a heat transfer of 16-18 W/m is sufficient. For sizes DN 25-40, a more powerful cable is needed - from 20 to 30 W/m or two small ones of 10-15 W/m.
Instructions for outdoor installation
To make an external water heating circuit, in addition to the wires themselves, you will need fastening means - aluminum tape and plastic clamps - tightening. The work is performed in the following order:
- Along the bottom of the pipe, where you plan to attach the heating cable for the water supply, stick a strip of aluminum tape. It will serve as a good heat dissipator.
- Apply a flat self-regulating conductor to the pipeline without twisting and secure it on top with a second strip of foil.
- Secure the heating element by pulling it to the main line with clamps every 20 cm, as shown in the photo below.
- To protect the shut-off valves from the cold, it is necessary to leave an allowance in the form of a hanging loop and continue installing the straight section. Then wrap a loop around the faucet or valve, glue it with tape and secure it with clamps.
Important point. If instead of one line you need to lay two, then place them along the bottom at an angle of 30° to the vertical axis on each side.
For water mains running along the street, it is better to lay the cable in the form of a spiral, providing more efficient heating. The same applies to large-diameter pipes, when spiral installation becomes more profitable than laying 3-4 straight lines. The fastening technology remains unchanged - gluing foil and fixing it with clamps is carried out on all types of pipes - plastic and metal.
The last stage is thermal insulation of the pipeline, without which its heating loses all meaning. For insulation, sleeves made of foamed polyethylene or foam shells are used. Before installing the thermal insulation layer, do not forget to check the functionality of the cable heating of your communications. The process is shown in more detail in the video:
Embedding the circuit into the pipe
To successfully push the heating cable into the pipeline, you should select a ready-made feed-through kit of the required diameter. It includes the following details:
- housing with external or internal thread;
- rubber seal;
- 2 bronze washers;
- hollow clamp nut.
The unit is installed in the place where the water supply makes a 90° turn, only instead of an elbow a tee is mounted at this point. It is also very desirable that all turns in the supply line be made naturally - due to the permissible bending of the pipe (excluding steel and polypropylene). When there are no fittings on the line, pushing the heating conductor in is much easier, as is pulling it out for repairs.
Advice. When choosing a cable for indoor installation in a store, pay attention to brands with a certificate allowing the use of these products with drinking-quality water.
Installation is carried out in the following sequence:
- Place a brass tee at the bend in the water line.
- If possible, straighten the twisted cable and pull the parts onto it in this order: nut, first washer, sealing gland, second washer.
- Screw the housing of the pass-through assembly into the tee, insert the wire there and push it to the required depth.
- Insert the washers into the socket along with the oil seal and tighten the nut.
Sequence of installation of parts
It is important here to assemble all the parts in the correct order, and before cutting the cable and installing the end sleeve, otherwise it will be difficult to tighten the gland. According to reviews on the forums, this method of heating communications is quite often practiced at the entrances to frame houses built on pile foundations. Subtleties installation work demonstrated in the next video:
Cutting and joining instructions
We decided to give Special attention at this point, because no homemade twists are suitable for joining such cables. To make the contact reliable and sealed (after all, the supply voltage is 220 Volts), connect power wire with a heating one you need using a special kit. It is purchased separately and consists of heat-shrinkable sleeves of various diameters and metal crimp ends.
The step-by-step docking procedure looks like this:
- Carefully cut and remove the top layer of insulation from the end of the heating cable to a length of 45 mm. Using a knife, separate the cores by cutting the semiconductor matrix lengthwise.
- Place protective tubes on the ends different lengths(the thinnest ones included). Heat them up construction hairdryer for shrinkage. Bite off the core with a short cover so that it protrudes 9-10 mm, and then expose both contacts, stripping the insulation down to the heat shrink tubes.
- Place the sleeves on the exposed wires and crimp them on one side with pliers or wire cutters. Take 2 tubes with an adhesive layer and put them on the prepared ends of the cable.
- Having previously removed the insulation, alternately pull the large and medium covers from the kit onto the power wire. Bend the grounding conductor (yellow) to the side, and expose the remaining two.
- Insert the ends of the power cord into the sleeves and crimp them on the other side. Move the previously installed small tubes onto the contacts and treat them with a hairdryer.
- Slide a medium-sized cover over the joint and heat it with a hairdryer to shrink it. Repeat the operation with the largest tube. At this point the sealed joint is ready.
Note. If your heating cable has braided shielding, then before insulating it with large covers, it must be connected to the grounding conductor of the power cord.
To complete the second end of the heating wire, you must install an end sleeve (sold separately). To do this, divide its strands with wire cutters to a length of 2 cm and remove the sheath from one of them, then put on a sleeve and use a hairdryer to shrink it. The operation is clearly shown in the video:
Conclusion
There are many instructions published on the Internet for organizing cable heating of water supply in a private home, but none of them talk about the consequences of a long power outage. Yes, frost protection with heating conductors is effective, but in some situations it does not save. There are 2 ways to survive an unpleasant moment: you can ensure a constant flow of water through the pipe (if we are talking about a centralized supply). The second option is to wrap a hose around the area and periodically run boiling water over it.
Design engineer with more than 8 years of experience in construction.
Graduated from Eastern Ukrainian National University them. Vladimir Dal with a degree in Electronics Industry Equipment in 2011.
Related posts:
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This text may be difficult to correctly perceive without reading my article.
The heating cables in question are designed to prevent water from freezing in water pipes in winter.
First, the output:
The “correct” heating system is a mandatory combination of a high-quality heating cable with a high-quality and high-precision thermostat.
No, even good (modern) heating cables without a thermal relay are suitable for long-term reliable and economical operation, including “samregs” (see my link about them).
Below I will try to explain this, and also tell you how to properly build heating systems.
If the heating cable is installed on top of a water pipe running from the ground into the house, then replacing it if it fails becomes a big problem. Even if this problem is easily solved (for example, with a cable inside a heated pipe), then the reliability of this system (especially in cold weather) still has a very high priority - in the winter of 2009-2010 (very very coldy) A huge number of people's water pipes froze.
Therefore, I take maximum reliability and durability of the heating system as my goal.
The heating cables themselves have a limited time between failures, so if they are turned on as rarely as possible, their lifespan will increase accordingly. Electricity consumption also matters (especially when the heating is constantly on).
The main idea:
If the temperature of the pipe is close to the temperature of the water in the well or well, this means that there is no point in heating it, or rather it is even harmful (for the heating cable). Therefore, the heating cable shutdown temperature should be slightly less than the winter (February) water temperature in your well/well ,
which is usually 5-6*C.
How to make the “correct” heating system for water pipes:
We take a high-quality, durable heating cable (it doesn’t matter whether it is self-regulating or not, the main thing is its lifespan and a sufficient number of on-off switches), wind it around a water pipe, as required by the instructions. There, close to the pipe in its coldest place (it is near the surface of the earth), we install a temperature sensor, and on top (in the house) - a thermal relay on which we set the on t of 2-3 degrees Celsius and the off t of 3-4 degrees. These numbers are because in winter (at the very coldest) the water in a well or well has a temperature of 5-6 degrees.
We thermally insulate the entire pipe (together with the sensor) with insulation with a thickness of at least 20 mm (in fact, for your wallet in the future, the more, the better). And we correctly connect all this to the 230V network.
The result was the most best option using a heating cable to heat a water pipe according to the criteria of minimum electricity consumption and maximum cable life.
When using a special heating cable inserted inside a water pipe, nothing fundamentally changes.
If you use a heating cable without a thermal relay (including a self-regulating one), then the result is an overconsumption of both energy and cable life. Moreover, many times compared to the approach I described. And also - the impossibility of monitoring the performance of this entire subsystem, which is no less important!
About choosing the power of the heating cable for water pipes:
If you do everything correctly (as I described above), then saving on the power of the heating cable is almost pointless, because the system will turn on quite rarely and with a higher power it will simply heat up faster, consuming approximately the same amount of energy as with a lower one. Power reserve won't hurt.
In general, it is considered this way: if the cable is installed inside the pipe, then 10 W/m is enough, and if outside, then 17 W/m. I would take a little more for reserve.
About protective subsystems.
Due to the fact that cases of heating cables and even HDPE pipes melting are quite common, it is necessary to understand that such a cable must be equipped with a 1-2 Ampere machine, and not 6 or 16 Amperes. Also, an RCD would not hurt in this circuit.
For meltdowns, see and.
About the thermostat and temperature sensor:
Ideally, you need a small sealed sensor with a digital thermostat located in the house.
If we do not take into account reliability (it is unknown to me), then the following would be suitable: a TR-35M thermostat, or a TSTAB thermostat.
Personally, my boiler and " " are controlled by RT-12-16. Satisfied.
It is better to seal the temperature sensor itself.
What not to do:
1. It is not necessary, for example, to use “Nelson EasyHeat resistive cable” without a thermal relay to heat the pipe coming from a well or well into the house. Why?
Because here the cable will turn off only at +13 degrees. And in wells, such a high temperature most likely never occurs even in summer. This means that the cable will wastelessly heat up the borehole/well water! And turning it off manually, for example, in early spring, risks freezing your water supply pipe on a cold night.
2. The temperature sensor should not be installed in close proximity to the heating cable, otherwise the system will not work properly. It must be placed on the opposite side of the water pipe from the heating cable and carefully insulated from the heating cable (but not from the pipe!). This, by the way, is the most unpleasant drawback in the heating system - the heater and meter should be as far away from each other as possible, and this is really difficult to achieve.
3. You cannot use insulation that can get wet (cotton wool). Also, you should not let the earth compress the insulation too much. In either of the two cases, it will become poorly insulated.
You can use, for example, foamed polyethylene (necessarily with closed cells) with a rigid pipe on top. For example, on a HDPE-32mm pipe you put a standard “stocking” of insulation, on top of another stocking of a larger diameter and put it all into a sewer pipe with a diameter of 110mm. After such installation, you can probably foam the remaining space (I foamed it to a depth of 1.3 meters, one 750g bottle of foam was just enough). It is better to foam with two-component foam; regular foam may not all freeze inside, because... it does not have access to moist air, which ensures the hardening of the foam.
Although, it is clear that with very good insulation, the temperature of the pipe may not drop to 2-3°C at all, but no one can guarantee this. At a minimum, due to uncertainty about the preservation of the properties of the insulation throughout the entire service life of the system (several decades).
Monitoring the performance of the system with a heating cable:
If you ever see that the temperature is lower than the set temperature, this means that the system is not working correctly or has failed.
Also, you can periodically check the performance of the system by temporarily changing the switching temperature of the thermal relay ("adjusting" it to the temperature of the pipe) and observe the switching on/off of the relay by its click and indicator.
There is also an 8-year practice of another of our forum members, confirming this theoretical study of mine (the link was lost when the forum “engine” was changed). If anyone finds it, please let me know.
Notes:
1. Sewer pipes As a rule, there is no need to heat it. They only need to provide the correct, strictly optimal slope.
2. If the street horizontal part of the water pipe is laid deep enough, or insulated (including snow), then it is most likely not necessary to heat it. But only the control system provides guarantees...
3. On a related topic you can read:
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4. And here is an almost free heating cable for DIYers:
kostiksamara said:
The power supply from the computer is 300 watts, I took a 12V (15 Ampere) output wire in PVC insulation with a cross-section of 1mm. The length of the loop is 20 meters, that is, 40 linear meters. the wire feels warm to the touch, 40 degrees
And also a whole topic:
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6. If a heating cable is used to be inserted into a water pipe, then for safety reasons its coupling must be grounded. I also consider it desirable to make an additional potential equalization system in the bathroom - DSUP (in addition to the main SUP). The presence of a 10-30 mA RCD is implied.
Heating cable is a type of cable used to heat water pipes and roofs from freezing in winter. You can connect the heating cable yourself.
How does a heating cable work?
The operating principle of the heating cable is the generation of electricity into heat without the use of fuel. Heating is carried out through the influence of electric current passing through the cable to prevent freezing of communications. The cable sheath material easily withstands low and high temperatures and external natural influences. Inside the cable sheath there is a heating element that turns on when the temperature drops, heating the structures on which it is installed, and turns off when the temperature rises.
Heating cables are divided into several types:
- Resistive: linear single-core cable that cannot be cut, otherwise it will cause overheating or melting of the cable insulation sheath, which can be life-threatening. Zonal two-core cable, which can be cut into lengths of at least two meters
- Self-regulating cable- one of the most convenient types of two-core cables that can be cut
- Magnetic cable: the cable cores are wrapped around the heating magnetic element
Heating cable installation areas
The heating cable should be laid in icy areas:
- For gutters: choose a cable with a power of up to 300 W on square meter
- Along drainpipes: laying two cable lines with a capacity of 20 W per meter
- In roof valleys: cable with power 250-300 W per square meter, stacked in up and down directions
- On the roof eaves using a “snake” pattern: the connection diagram for a self-regulating heating cable involves installation along the edge of the eaves
How to connect a heating cable
- The pipe must not be damaged
- Installation on a painted pipe is only permissible after the paint has completely dried.
- It is necessary to inspect the pipe to check for the presence of sharp elements to prevent damage to the heating cable network
There are several ways to install a cable heating network:
- Linear installation- a method characterized by laying a self-regulating heating cable along the pipe. Installation of one or more cables on one section of pipe is permitted. Laying is carried out according to following diagram: the cut pipe is symbolically represented by a watch dial, the first cable is mounted on the pipe at the position of four hours and thirty minutes, the next cable is attached to the position of seven hours and thirty minutes. If the heating network includes 4 heating cables, they should be placed correctly: at positions one hour thirty minutes, four hours thirty minutes, seven hours thirty minutes and ten hours thirty minutes
- Spiral installation- a method involving spiral installation of a self-regulating heating cable on a pipe. This method is used when the linear method is not possible
- Internal installation- a method that involves inserting a self-regulating heating cable along the pipe to the required length