Despite the fact that today’s market offers the consumer many types of household heating appliances, handicraft heating appliances are quite common in everyday life.
In most cases, the reason for using homemade devices is the reluctance to spend money on the purchase of an industrial production unit, the cost of which, especially from a well-known manufacturer, can be significant. This is especially true for situations where the heater is not purchased for an apartment, and the efficiency of the installed air heater is erroneously prioritized, and not its safety and aesthetics.
Without discussing the degree of validity of such reasons, we will consider how to assemble a heater with our own hands from improvised means in order to minimize the risks of operating such equipment.
Homemade heaters — arguments for and against
As a rule, handicraft heat generators are copies of industrially produced devices. These copies, with rare exceptions, are inferior to the originals in many ways, but due to certain circumstances, the consumer often chooses a home-made unit.
The «pros» of using handicraft devices:
- relatively low cost (when making with your own hands and using improvised means);
- the possibility of assembling the unit of the required dimensions and manufacturing the body with the desired strength characteristics, up to anti-vandal design.
The main argument «against» — an uncertain degree of safety of home-made heating devices during operation, fraught with unpredictable negative consequences not only for the owner of the unit, but also for others.
This argument is due to many factors, and its validity is confirmed annually by numerous fires caused by handicraft heaters used in violation of the Decree of the Government of the Russian Federation. «On the fire regime» No. 390 dated April 25, 2012 (as amended on November 18, 2017)
As for the secondary arguments «against», they are as follows:
- lack of legitimate manufacturer’s warranties;
- the uncertainty of some characteristics of home-made devices;
- low aesthetics and degree of automation of handicraft units.
If familiarization with these arguments still did not prompt you to purchase a factory-made heater in the store, consider how to make a heater yourself so that the likelihood of an accident when using it is as small as possible.
Cast iron radiator electric heater
Sectional prefabricated cast iron batteries, traditionally used in water or steam heating systems, can also be used as a housing in the manufacture of electric — based on heating element DIY heater.
Preparing the body of the heat generator
Depending on the location and area of the room, a cast-iron radiator with the required number of sections is selected and its condition is visually assessed. If the device has not been used for a long time, you will have to disassemble it, clean the threaded connections, free the sections from scale and reassemble the device using new seals in the threaded connections. It is necessary to do this, since oil or an antifreeze solution (high permeability liquid) will be poured into the tank, and the unit is likely to leak through old cracked thread seals.
If there are no skills in this work, it is better to seek help from a professional — this will also eliminate the need to search for special keys.
Important! After disassembling and cleaning the threaded connections, until the radiator is assembled, it is easier to remove old paint from its sections — this is done using a grinder or a drill with a steel brush nozzle. But this operation can be performed later — after assembling the battery.
After the radiator is assembled, first of all, its capacity is determined — temporarily screw the plugs into three of the four holes, completely fill the unit with water, and then drain it into a measuring vessel. This is necessary to determine the need for oil or antifreeze, and at the same time to pre-test the device for leaks.
After cleaning with a grinder, the product is treated with coarse sandpaper, cleaned of dust and degreased with a nitro solvent. Then the radiator is covered with a primer and, after it dries, with one layer of topcoat paint. Painting is done with a spray gun or a narrow brush with a long handle.
The choice of heating element and its installation
For the future electric heater, it is necessary to select a tubular electric heater of the required power and the design that is as safe as possible for this device.
Important! A simplified basis for calculating the required power consumed by the heater is the rule — for heating 1 m2 premises in central Russia, the main heating unit requires 100 W of energy, and an additional heating device — 2-4 times less.
That is, averaged for the main heating of a room with an area of 20 m2 the battery must be equipped with a heating element with a capacity of 2 kW of power consumed.
The power of the tubular heater must be within 0.75% of the heat output of the battery so that the heater does not heat up and turn off too quickly — this reduces the efficiency of the heater. The average heat transfer value of one section of the cast-iron battery is 140 watts. This means that the heat transfer of a radiator of 10 sections will be 1.4 kW, and the power of the heating element should not exceed ¾ of this value — 1.05 kW. Thus, in a room of 20 m2 as the main heating devices, it is necessary to install 2 cast-iron electric radiators of 10 sections, each of which is equipped with a heating element with a power of 1 kW.
When choosing a tubular electric heater, it should be borne in mind that, ideally, its length should be 10 cm less than the width of the battery — this is how uniform heating and antifreeze convection occurs in all sections. Be sure to purchase a heating element with a thermostat — such a unit will increase the relative safety of the heater and ensure operation in a relatively economical mode.
If the heater is planned to be used for heating non-residential premises, then after installation at the design site it can be equipped with an expansion tank — through the fitting on one of the sides in the upper part of the battery, a plug is installed on the opposite side of the radiator. This will not benefit the aesthetics of the device, but it will eliminate the pressure factor from the inside on the radiator of the filler expanding when heated.
If the tank is not used, then a Mayevsky crane is mounted in the futorka instead of its supply pipe — for the possibility of emergency pressure relief.
A heating element is screwed into the lower part of the radiator on one side, and a plug on the opposite side.
Before installing the heater, transformer oil or antifreeze is poured into the battery in an amount of 80-85% of its volume. The external thread of the heating elements (an inch and a quarter) is identical to the internal thread on the battery, so the installation of the assembly is not difficult.
Filling up the battery
The type of filler is determined (antifreeze, transformer oil or water), and the required amount is calculated — 80-85% of the volume of water that was previously drained into a measuring tank from a completely filled radiator.
Important! If the temperature in the room with the heater off drops below zero, then the use of water as a filler for the battery is dangerous — if it is not drained in time, it will freeze and destroy the unit.
The sequence of actions when pouring liquid into the battery is as follows:
- a heating element is screwed into the lower part of the battery on one side, and a plug on the other;
- a plug is installed in the upper part of the radiator on one side;
- the heater is placed vertically — up with the remaining open hole, and filler is poured into the unit through it;
- the section of the wall behind the installed electric heater is equipped with thermal insulation from a layer of foil foam with an excess of 10-15 cm in size in each direction — this will reduce heat loss for heating the building envelope;
- the heater is placed at the design site, after which a fitting is mounted in its upper free nest, to which a Mayevsky tap or expansion tank pipe is connected.
Important! A home-made electric heater made of a cast-iron battery must be equipped with a separate supply line with an individual automatic shutdown device.
To get a better understanding of the technology described above, watch this video:
Electric spiral heater
A small homemade garage heater can be made in almost a couple of hours.
To do this, you will need the following materials and tools:
- refractory (chamotte) brick — 2 pcs.;
- nichrome spiral — 1.2-1.5 m;
- steel or aluminum corner 35×35 or 40×40 mm — 1.5 m;
- small grinder with discs: for stone and cutting for metal;
- drill with drills: for metal — Ø 3mm, victorious — Ø 6-8 mm;
- narrow chisel with a hammer;
- blind rivets with a key.
The device to be made will be an insulator base of two bricks with a spiral embedded in them, located on a bed of angle steel.
A square 250×250 mm (the length of a brick) is drawn on a sheet of paper, in which the spiral layout is arranged — a labyrinth of stripes 1 cm wide, directed from the edges of the square to the center.
Bricks, which are selected with good geometry and without chips, are cleaned, washed, dried and placed on a flat surface next to each other to form a square. The contour of the labyrinth drawn on the sheet is transferred to this square.
A grinder with a disk on a stone (dry cutter) forms a furrow on the bricks. Along the boundaries of the groove, even cuts are made to a depth of 1 cm, and then the core between them is selected with the side edge of the same disk — so the bottom of the groove turns out to be even.
If you cut down the middle between the cuts with a chisel, then there is a risk of splitting the brick, besides, with a successful outcome, you still have to level the bottom of the furrow with a grinder.
Forming straight sections of the groove on the bricks with a disc, it is not necessary to go beyond the boundaries of the contour at turns in order to fulfill the required depth of the groove — this is carefully done with a small chisel, which can be made from an M10 tap or a Ø10 mm drill.
After the formation of the groove, a spiral is laid in it.
Important! In order to be able to put containers on the heater to warm up the contents, the spiral laid in the furrow should be 3-5 mm below the plane of the bricks.
In the grooves of the beginning of the “labyrinth”, two through holes with a diameter of 6-8 mm are made with a drill with a pobedite tip — for the subsequent connection of the ends of the spiral to the supply cable.
Then they begin to manufacture a tripod from angle steel for installing bricks in it.
A grinder with a cutting disc for metal cuts a corner to size — 4 elements for the frame and 4 support legs. Pieces of the corner can be connected in two ways:
- electric welding, having previously cut the ends of the fragments for the frame at an angle of 45about;
- blind rivets, drilling holes in elements superimposed on top of each other.
The thickness of the brick is 5.5-6.5 cm, so at both ends of the spiral we straighten several turns to even sections about 10 cm long. The straightened ends of the spiral are drawn down through the holes in the brick and connected to the ends of the power cable.
The heater is set to the working position, the spiral is distributed in the groove until it is uniformly slightly tensioned along the entire length.
Perform a test connection of the device to the network. Wiring and automatic line disconnection must be designed for a power of at least 3 kW.
After the device enters the operating mode, its spiral should not be bright red, but brown-crimson.
With excessive heating of the spiral, it is necessary to reduce the current strength, which is done by adding a 20-40 A diode to the circuit.
The power consumption of such a home-made heater cannot be called economical, but it is quite acceptable for short-term inclusions — minor car repairs in the garage, for a small greenhouse as an emergency means of heating, heating food, etc.
You can make a homemade heater in many other ways — using sunlight, a car battery, liquid energy carriers, but the chosen technology must combine a well-thought-out degree of safety, the necessary efficiency of the unit and sufficient competence of the manufacturer. The heat generators described above have such a combination of criteria.
The main essence of the article
- Handicraft heaters have not become obsolete even in the conditions of saturation of the modern market with industrial heating equipment.
- The use of home-made heaters is prohibited by the current Fire Safety Rules, therefore, the responsibility for the consequences of their use lies entirely with the consumer.
- An electric heater made of a sectional cast-iron radiator based on a heating element is a durable, efficient unit, but not economical due to increased electricity consumption. However, given its relative safety compared to liquid-fuel devices, the device is made by craftsmen and is used in everyday life quite often.
- An electric heater made of a nichrome spiral on a ceramic brick frame is a device that can be self-made in a couple of hours without special professional skills. The efficiency of the device with its compactness depends on the spiral used, does not imply the efficiency of the unit, but is combined with a relatively low degree of risk of operation.
- The choice of a heater for home-made production should be based on a successful combination of three characteristics — a well-thought-out degree of safety, the necessary efficiency, and the competence of the manufacturer sufficient for assembly.