The main units of an instantaneous water heater (Fig. 12.3) are: a gas burner device, a heat exchanger, an automation system and a gas outlet.
Gas low pressure fed to the injection burner 8 ... The combustion products pass through the heat exchanger and are discharged into the chimney. The heat of the combustion products is transferred to the water flowing through the heat exchanger. A coil serves to cool the fire chamber 10 through which the water circulates, passing through the heater.
Gas instantaneous water heaters are equipped with gas outlet devices and traction interrupters, which, in the event of a short-term loss of draft, prevent the flame from going out
gas burner device. There is a flue pipe for connection to the chimney.
Flowing water heaters intended to receive hot water where it is not possible to provide it in a centralized manner (from a boiler house or a heating plant), and refer to devices of immediate action.
Rice. 12.3. Schematic diagram instantaneous water heater:
1 – reflector; 2 – top cap; 3 – bottom cap; 4 – heater; 5 – igniter; 6 – casing; 7 – block crane; 8 – burner; 9 – fire chamber; 10 – coil
The devices are equipped with gas outlet devices and traction breakers, which prevent the flame of the gas burner device from extinguishing in the event of a short-term disruption of the draft. There is a flue pipe for connection to the flue duct.
According to the rated thermal load, the devices are subdivided:
With a rated thermal load of 20934 W;
With a rated thermal load of 29075 W.
Domestic industry serially produces household gas flow-through water heaters VPG-20-1-3-P and VPG-23-1-3-P. The technical characteristics of these water heaters are given in table. 12.2. Currently, new types of water heaters are being developed, but their design is close to the current ones.
All the main elements of the apparatus are mounted in a rectangular enamel casing.
The front and side walls of the casing are removable, which creates convenient and easy access to the internal units of the device for preventive examinations and repairs without removing the device from the wall.
Water-heating flow-through gas devices of the VPG type are used, the design of which is shown in Fig. 12.4.
On the front wall of the casing of the apparatus, there is a gas valve control knob, a button for switching on the solenoid valve and a viewing window for observing the flame of the pilot and main burners. Above the device there is a gas outlet device, which serves to remove combustion products into the chimney, at the bottom there are nozzles for connecting the device to the gas and water networks.
Geysers Neva 3208 (and similar models without automatic water temperature control L-3, VPG-18 \ 20, VPG-23, Neva 3210, Neva 3212, Neva 3216, Darina 3010) are often found in houses without centralized hot water supply. This column has simple design and therefore very reliable. But she sometimes surprises. Today we will tell you what to do if the pressure of hot water suddenly becomes too weak.
Gas water heater Neva 3208, or more precisely - flowing gas water heater wall type is a device for obtaining hot water using the energy of combustion of natural gas. The gas water heater is an unpretentious and easy-to-use thing. Of course, according to the idea of communal services, centralized hot water supply is more convenient, but in practice it is still not known which is better. The hot water from the pipe is now rusty, then barely warm, and the payment bites. And about the notorious summer blackouts, during which the owners gas water heaters with a smile, they listen to stories about heating water in a basin on the stove, and it's not worth mentioning.
So, one morning the column turned on properly, but the pressure of water from the hot water tap in the bath appeared too weak... And when the shower was turned on, the column went out completely. Meanwhile, the cold water continued to flow in a brisk stream. Suspicion first fell on the mixer, but the same situation was found in the kitchen. There was no doubt that it was the gas water heater. Old lady Neva 3208 presented a surprise.
Attempts to call a foreman for repair ended, in fact, in failure. All the masters directly by telephone "diagnosed" in absentia that heat exchanger clogged with scale and offered to either replace it (2500-3000 rubles for a new one, 1500 rubles for a repaired one, not counting the cost of work), or wash it on the spot (700-1000 rubles). And only on such conditions did they agree to a visit. But it didn't look like a clogged heat exchanger at all. The previous evening, the pressure was normal and during the night, scale could not build up. Therefore, it was decided to carry out the repairs on their own. By the way, you can also carry out repairs if the column does not turn on at normal pressure - most likely, it broke membrane in the water unit and needs to be replaced.
The Neva 3208 geyser is installed on the wall of the kitchen or, less often, the bathroom.
Before starting the repair, it is necessary to turn off the column, turn off the gas supply and cold water.
To remove the shroud, you must first remove the flame control knob. It is fixed on the rod with a spring and removed by simple pulling on itself, there are no fasteners. Valve button gas safety and the plastic pad stays in place, they don't get in the way. Removing the handle gives access to the two mounting screws.
In addition to the screws, the casing is held in place by four pins located at the top and bottom at the rear. After loosening the screws Bottom part the casing is pulled forward by 4-5 cm (the lower pins are released) and whole casing goes down (the upper pins are released). Before us internal organization gas water heater.
Our problem is at the bottom, the so-called "water" part of the column. This part is sometimes referred to as the "frog". In function water unit includes turning on and off the column depending on the presence or absence of water flow. The principle of operation is based on the properties of the Venturi nozzle.
The water unit is fastened with two union nuts to the water supply pipes and three screws to the gas part.
But before removing the water unit, you need to take care of the water in the column. V last resort, a wide basin can be substituted under the column during disassembly. But you can drain the water more carefully through stub located at the bottom of the water unit.
To do this, unscrew the plug and open any hot water tap after the column for air access. About half a liter of water is poured out.
By the way, through this plug you can try to flush the blockage without removing the water unit. This is done reverse current water. With the plug removed (do not forget to substitute a bucket or basin) in the mixer in the kitchen or bathroom, open both taps and clamp the spout. Cold water will reverse flow through the hot water pipes and maybe push the blockage out.
After draining the water, the water unit can be removed without fear. We unscrew the union nuts, move the tubes to the sides a little, loosen the three screws on the gas part and take the assembly down.
By the way, under the left nut in the recess of the water unit there is filter in the form of a piece of brass mesh. It needs to be pulled out with a needle and cleaned well. When removed, this filter crumbled to pieces from old age. Considering that in the apartment after the riser there is already a pre-filter mesh, and the pipes are made of metal-plastic, it was decided not to bother with the new one. If the pipes are steel or there is no filter on the riser, then the filter at the inlet to the water unit must be left behind, otherwise the column will have to be cleaned almost monthly. A new filter can be made from a piece copper or brass mesh.
The cover of the water unit is held in place by eight screws. In the old designs, the case was silumin, and the screws were steel, and it was often very difficult to unscrew them. In the Neva 3208, the body and screws are brass. After removing the cover, you can see membrane.
In older models, the membrane was rubber flat, so it worked in tension and broke rather quickly. Replacing the membrane every one to two years was a routine operation. In Neva 3208, the membrane is silicone and profiled. It hardly stretches during work and lasts much longer. But in case of problems, replacing the membrane is quite simple, the main thing is to find a high-quality silicone one. And, finally, under the membrane is the cavity of the water unit.
Several small specks were found in it. But the main problem was right outlet channel... There is a narrow nozzle (about 3 mm), which creates a pressure drop for the operation of the water unit. It was it that was almost completely covered by a very firmly stuck rust flake. It is better to clean the nozzle with a wooden stick or a piece of copper wire so as not to spoil the diameter.
Now it remains to collect everything back. It also has its own subtleties... The membrane is first installed in the cover of the water unit. In this case, it is important not to put it upside down and not to block the fitting connecting the halves of the water unit (arrow in the photo)
Now all eight screws are in place, held in place by the elasticity of the edges of the holes in the membrane.
The cover is installed on the body (do not confuse - which side, look at the correct position in the photo) and the screws carefully, 1-2 turns in turn are folded crosswise, preventing the cover from skewing. This assembly prevents the membrane from deforming or tearing.
After that, the water unit is installed in the gas section and slightly fixed with screws. Finally, the screws are tightened after connecting the water pipes. Then water is supplied and the connections are checked for leaks. It is not necessary to be zealous with tightening the nuts, if a slight tightening does not help, then it is required replacement gaskets. You can buy them or make them yourself from sheet rubber with a thickness of 2-3 mm.
It remains to put the casing in place. It is better to do this together, because it is very difficult to get on the pins almost blindly.
That's all! The repair took 15 minutes and was completely free. The video shows the same thing more clearly.
# 63 Yuri Makarov 09/22/2017 11:43
I quote Dmitry:
The names of the columns produced in Russia often contain the letters VPG: this is a water-heating device (V) flow-through (P) gas (G). The number after the letters HSG indicates the heat output of the apparatus in kilowatts (kW). For example, VPG-23 is a flow-through gas water-heating apparatus with a thermal power of 23 kW. Thus, the name of modern speakers does not define their design.
The VPG-23 water heater was created on the basis of the VPG-18 water heater manufactured in Leningrad. Later, VPG-23 was produced in the 90s at a number of enterprises in the USSR, and then - SIG. A number of such devices are in operation. Individual nodes, for example water part, finds application in some models of modern Neva speakers.
The main specifications VPG-23:
VPG-23 consists of a gas outlet, a heat exchanger, a main burner, a valve block and an electromagnetic valve (Fig. 74).
The gas outlet serves to supply combustion products to the flue gas outlet of the column. The heat exchanger consists of an air heater and a fire chamber, surrounded by a cold water coil. The height of the VPG-23 fire chamber is less than that of the KGI-56, because the VPG burner provides better mixing of gas with air, and the gas burns with a shorter flame. A significant number of HPG columns have a heat exchanger consisting of one air heater. In this case, the walls of the fire chamber were made of steel sheet, the coil was absent, which made it possible to save copper. The main burner is multi-nozzle, it consists of 13 sections and a manifold, connected by two screws. The sections are assembled into a single whole with tie bolts. The manifold has 13 nozzles, each of which blows gas into its own section.
The block valve consists of gas and water parts, connected by three screws (Fig. 75). The gas part of the block valve consists of a body, a valve, a valve plug, a gas valve cover. A tapered liner for the gas valve plug is pressed into the body. The valve has a rubber seal on the outside diameter. A cone spring presses on it from above. The seat of the safety valve is made in the form of a brass insert pressed into the body of the gas part. The gas valve has a handle with a limiter that fixes the opening of the gas supply to the igniter. The valve plug is pressed against the tapered liner by a large spring.
There is a groove on the valve plug for gas supply to the igniter. When the valve is turned from the extreme left position by an angle of 40 °, the groove coincides with the gas supply hole, and gas begins to flow to the igniter. In order to supply gas to the main burner, the tap handle must be pressed and turned further.
The water part consists of the lower and upper covers, a Venturi nozzle, a diaphragm, a plate with a stem, an ignition retarder, a stem oil seal and a stem clamping sleeve. Water is supplied to the water part on the left, enters the under-membrane space, creating a pressure in it equal to the water pressure in the water supply system. After creating pressure under the membrane, the water flows through the venturi nozzle and rushes to the heat exchanger. The venturi nozzle is a brass tube, in the narrowest part of which there are four through holes that go into the outer circular groove. The groove matches the through holes in both water end covers. Through these holes, the pressure from the narrowest part of the venturi nozzle will be transferred to the supra-membrane space. The poppet stem is sealed with a nut that compresses the PTFE packing.
Automation works on the water flow as follows. When water passes through the Venturi nozzle, in the narrowest part, the highest speed of movement of water and, therefore, the lowest pressure. This pressure is transmitted through the through holes to the supra-membrane cavity of the water part. As a result, a differential pressure appears below and above the membrane, which bends upward and pushes the plate with the stem. The stem of the water part, abutting against the stem of the gas part, lifts the valve from the seat. This opens the gas passage to the main burner. When the water flow is stopped, the pressure under and above the membrane is equalized. The cone spring presses on the valve and presses it against the seat, the gas supply to the main burner is stopped.
The solenoid valve (Fig. 76) is used to shut off the gas supply when the igniter goes out.
When you press the solenoid valve button, its stem rests on the valve and moves it away from the seat, while compressing the spring. At the same time, the armature is pressed against the core of the electromagnet. At the same time, gas begins to flow into the gas part of the block valve. After igniting the igniter, the flame begins to heat the thermocouple, the end of which is set in a strictly defined position in relation to the igniter (Fig. 77).
The voltage generated during the heating of the thermocouple is applied to the winding of the electromagnet core. In this case, the core holds the armature, and with it the valve, in the open position. The time during which the thermocouple generates the required thermo-EMF and solenoid valve starts to hold the anchor, is about 60 sec. When the igniter goes out, the thermocouple cools down and stops generating voltage. The core no longer holds the armature; the spring closes the valve. The gas supply to both the igniter and the main burner is cut off.
The draft automatics turns off the gas supply to the main burner and the igniter if the draft in the chimney is disturbed; it works according to the principle of “gas removal from the igniter”. Traction automation consists of a tee that is attached to the gas part of the block valve, a tube to the traction sensor and the sensor itself.
Gas from the tee is supplied to both the igniter and the draft sensor installed under the gas outlet. The thrust sensor (Fig. 78) consists of a bimetallic plate and a union, secured with two nuts. The upper nut is at the same time a seat for the plug, which closes the gas outlet from the fitting. A pipe supplying gas from the tee is attached to the fitting with a union nut.
With normal draft, the combustion products go into the chimney without heating the bimetallic plate. The plug is tightly pressed against the seat, gas does not come out of the sensor. If the draft in the chimney is disturbed, the combustion products heat up the bimetallic plate. It bends upward and opens the gas outlet from the choke. The gas supply to the igniter decreases sharply, the flame stops heating the thermocouple normally. It cools down and stops generating tension. As a result, the solenoid valve closes.
The main malfunctions of the VPG-23 column include:
1. The main burner does not light up:
2. When the water intake is stopped, the main burner does not go out:
3. Violation of the electrical circuit between the thermocouple and the electromagnet (open circuit or short circuit). Possible reasons are as follows:
4. Insufficient heating of the thermocouple:
These water heaters (table 133) (GOST 19910-74) are installed mainly in gasified residential buildings equipped with plumbing, but not having a centralized hot water supply. They provide fast (within 2 minutes) heating of water (up to a temperature of 45 ° C), continuously supplied from the water supply.
In terms of equipment with automatic and regulating devices, the devices are divided into two classes.
Table 133. TECHNICAL DATA OF APPLIANCES OF WATER-HEATING FLOW HOUSEHOLD GAS
Note. Devices of type 1 - with the removal of combustion products into the chimney, type 2 - with the removal of combustion products into the room.
Devices of the highest class (B) have automatic safety and regulation devices that provide:
b) shutdown of the main burner in the absence of vacuum in
Chimney (type 1 apparatus);
c) regulation of water consumption;
d) regulation of gas flow or pressure (natural gas only).
All units are equipped with an externally controlled ignition device, and type 2 units are additionally equipped with a temperature selector.
Devices of the first class (P) are equipped with automatic ignition devices providing:
a) gas access to the main burner only in the presence of a pilot flame and a water flow;
b) shutdown of the main burner in the absence of vacuum in the Chimney (type 1 apparatus).
The pressure of the heated water at the inlet is 0.05-0.6 MPa (0.5-6 kgf / cm²).
The devices must have gas and water filters.
Apparatuses are connected to water and gas pipelines using union nuts or couplings with locknuts.
Conventional designation of a water heater with a nominal heat load of 21 kW (18 thousand kcal / h) with combustion products discharge into a chimney, operating on gases of the 2nd category, the first class: VPG-18-1-2 (GOST 19910-74).
Flowing gas water heaters KGI, GVA and L-3 are unified and have three models: VPG-8 (flowing gas water heater); VPG-18 and VPG-25 (Table 134).
Rice. 128. Flowing gas water heater VPG-18
1 - cold water pipe; 2 - gas cock; 3 - pilot burner; 4-gas outlet device; 5 - thermocouple; 6 - electromagnetic valve; 7 - gas pipeline; 8 - hot water pipe; 9 - thrust sensor; 10 - heat exchanger; 11 - main burner; 12 - water-gas unit with nozzle
Table 134. TECHNICAL DATA OF FLOW-FLOW UNIFIED WATER HEATERS VPG
| Indicators | Water heater model | ||
| VPG-8 | VPG-18 | VPG-25 | |
| Heat load, kW (kcal / h) Heating capacity, kW (kcal / h) Allowable water pressure, MPa (kgf / cm²) |
9,3 (8000) 85 | 2,1 (18000)
18 (15 300) 0,6 (6) |
2,9 (25 000) 85
25 (21 700) 0,6 (6) |
| Gas pressure, kPa (kgf / m 2): natural liquefied The volume of heated water for 1 min at 50 e С, l Diameter of fittings for water and gas, mm Diameter of the branch pipe for the removal of combustion products, mm |
|||
| Overall dimensions, mm; | |||
Table 135. TECHNICAL DATA OF GAS WATER HEATERS
| Indicators | Water heater model | |||
| KGI-56 | GVA-1 | GVA-3 | L-3 | |
| 29 (25 000) | 26 (22 500) | 25 (21 200) | 21 (18 000) | |
| Gas consumption, m 3 / h; | ||||
| natural | 2.94 | 2,65 | 2,5 | 2,12 |
| liquefied | - | - | 0,783 | |
| Water consumption, l / mn, temperature 60 ° С | 7,5 | 6 | 6 | 4,8 |
| Diameter of the branch pipe for the removal of combustion products, mm | 130 | 125 | 125 | 128 |
| Diameter of connecting nipples D mm: | ||||
| cold water | 15 | 20 | 20 | 15 |
| hot water | 15 | 15 | 15 | 15 |
| gas Dimensions, mm: height |
15 950 | 15 885 | 15 | 15 |
| width | 425 | 365 | 345 | 430 |
| depth | 255 | 230 | 256 | 257 |
| Weight, kg | 23 | 14 | 19,5 | 17,6 |
KGI-56 column malfunctions
Insufficient pressure water;
The hole in the under-membrane space is clogged - clean;
The stem does not move well in the stuffing box - re-seal the stuffing box and lubricate the stem.
2.When water intake stops, the main burner does not go out:
The hole in the supra-membrane space is clogged - clean;
Dirt has got under the safety valve - clean;
The small spring is weakened - replace;
The stem does not move well in the stuffing box - re-seal the stuffing box and lubricate the stem.
3. The radiator is clogged with soot:
Adjust the combustion of the main burner, clean the soot from the radiator.
VPG-23
The name of a modern speaker made in Russia almost always contains the letters HSV: it is a water-heating device (V) flowing (P) gas (G). The number after the letters HSG indicates the heat output of the apparatus in kilowatts (kW). For example, VPG-23 is a flow-through gas water-heating apparatus with a thermal power of 23 kW. Thus, the name of modern speakers does not define their design.
Water heater VPG-23 created on the basis of the VPG-18 water heater manufactured in Leningrad. Later VPG-23 was manufactured in the 80-90s. at a number of enterprises in the USSR, and then the CIS.
VPG-23 has the following technical characteristics:
thermal power - 23 kW;
water consumption when heated to 45 ° C - 6 l / min;
water pressure - 0.5-6 kgf / cm 2.
VPG-23 consists of a gas outlet, a radiator (heat exchanger), a main burner, a valve block and an electromagnetic valve (Fig. 23).
Gas outlet serves to supply combustion products to the flue pipe of the column.
The heat exchanger consists of from a heater and a fire chamber, surrounded by a cold water coil. The dimensions of the VPG-23 fire chamber are smaller than those of the KGI-56, because the VPG burner provides better mixing of gas with air, and the gas burns with a shorter flame. A significant number of HPG columns have a radiator consisting of one heater. In this case, the walls of the fire chamber are made of steel sheet, which saves copper.
Main burner consists of 13 sections and a manifold, connected by two screws. The sections are assembled into a single whole with tie bolts. The manifold has 13 nozzles, each of which supplies gas to its own section.
Rice. 23. Column VPG-23
The block crane consists of from the gas and water parts, connected by three screws (fig. 24).
Gas part the valve block consists of a body, a valve, a cone liner for a gas valve, a valve plug, a gas valve cover. The valve has a rubber seal on the outside diameter. A cone spring presses on it from above. The seat of the safety valve is made in the form of a brass insert pressed into the body of the gas part. The gas valve has a handle with a limiter that fixes the opening of the gas supply to the igniter. The valve plug is held in the body by a large spring. There is a groove on the valve plug for gas supply to the igniter. When the valve is turned from the extreme left position by an angle of 40 °, the groove coincides with the gas supply hole, and gas begins to flow to the igniter. In order to supply gas to the main burner, it is necessary to press the valve handle and turn further.
Rice. 24. Block crane VPG-23
Water part consists of lower and upper covers, Venturi nozzle, diaphragm, plate with stem, ignition retarder, stem oil seal and stem clamping sleeve. Water is supplied to the water part on the left, enters the under-membrane space, creating a pressure in it equal to the water pressure in the water supply system. After creating pressure under the membrane, the water flows through the venturi nozzle and rushes to the radiator. The venturi nozzle is a brass tube, in the narrowest part of which there are four through holes that go into the outer circular groove. The groove matches the through holes in both water end covers. Through these holes, the pressure from the narrowest part of the venturi nozzle is transferred to the supra-membrane space. The poppet stem is sealed with a nut that compresses the PTFE packing.
Automation works along the water flow in the following way. When water passes through the Venturi nozzle, in the narrowest part, the highest speed of movement of water and, therefore, the lowest pressure. This pressure is transmitted through the through holes to the supra-membrane cavity of the water part. As a result, a differential pressure appears below and above the membrane, which bends upward and pushes the plate with the stem. The stem of the water part, abutting against the stem of the gas part, raises the safety valve from the seat. This opens the gas passage to the main burner. When the water flow is stopped, the pressure under and above the membrane is equalized. The cone spring presses the safety valve and presses it against the seat, the gas supply to the main burner is cut off.
Solenoid valve(fig. 25) serves to shut off the gas supply when the igniter goes out.
Rice. 25. Solenoid valve VPG-23
When you press the solenoid valve button, its stem rests on the valve and moves it away from the seat, while compressing the spring. At the same time, the armature is pressed against the core of the electromagnet. At the same time, gas begins to flow into the gas part of the block valve. After igniting the igniter, the flame begins to heat the thermocouple, the end of which is set in a strictly defined position in relation to the igniter (Fig. 26).
Rice. 26. Installing the igniter and thermocouple
The voltage generated during the heating of the thermocouple is applied to the winding of the electromagnet core. The core begins to hold the armature, and with it the valve, in the open position. Solenoid valve response time - about 60 sec. When the igniter goes out, the thermocouple cools down and stops generating voltage. The core no longer holds the armature; the spring closes the valve. The gas supply to both the igniter and the main burner is cut off.
Traction automation cuts off the gas supply to the main burner and igniter if the draft in the chimney is disturbed. It works on the principle of "gas evacuation from the pilot".
Rice. 27. Traction sensor
Automation consists of a tee, which is attached to the gas part of the block valve, a tube to the draft sensor and the sensor itself. Gas from the tee is supplied to both the igniter and the draft sensor installed under the gas outlet. The thrust sensor (fig. 27) consists of a bimetallic plate and a union, secured with two nuts. The upper nut is at the same time a seat for the plug, which closes the gas outlet from the fitting. A pipe supplying gas from the tee is attached to the fitting with a union nut.
With normal draft, the combustion products go into the chimney without falling on the bimetallic plate. The plug is tightly pressed against the seat, gas does not come out of the sensor. If the draft in the chimney is disturbed, the combustion products heat up the bimetallic plate. It bends upward and opens the gas outlet from the choke. The gas supply to the igniter decreases sharply, the flame stops heating the thermocouple normally. It cools down and stops generating tension. As a result, the solenoid valve closes.
Malfunctions
1.The main burner does not light up:
Insufficient water pressure;
Deformation or rupture of the membrane - replace the membrane;
Clogged venturi nozzle - clean;
The stem came off the plate - replace the stem with the plate;
The misalignment of the gas part in relation to the water part - align with three screws;
2.When water intake is stopped, the main burner does not go out:
Dirt has got under the safety valve - clean;
Loose cone spring - replace;
The stem does not move well in the stuffing box - lubricate the stem and check the nut tightness.
3.When the pilot flame is present, the solenoid valve is not held open:
a) violation of electrical circuits between the thermocouple and the electromagnet - open or short circuit. Perhaps:
Lack of contact between the terminals of the thermocouple and the electromagnet;
Violation of the insulation of the copper wire of the thermocouple and its short circuit with the tube;
Violation of the insulation of the turns of the coil of the electromagnet, their closure to each other or to the core;
Disruption of the magnetic circuit between the armature and the core of the electromagnet coil due to oxidation, dirt, grease, etc. It is necessary to clean the surfaces with a piece of coarse cloth. It is not allowed to clean the surfaces with files, sandpaper, etc .;
b) insufficient heating thermocouples:
The working end of the thermocouple is soaked;
The ignition nozzle is clogged;
Thermocouple is incorrectly positioned relative to the igniter.
Column FAST
Instantaneous water heaters FAST have open chamber combustion, combustion products are removed from them due to natural draft. Columns FAST-11 CFP and FAST-11 CFE heat 11 liters of hot water per minute while heating water at 25 ° C
(∆T = 25 ° С), columns FAST-14 CF P and FAST-14 CF E - 14 l / min.
Flame control on FAST-11 CF P (FAST-14 CF P) produces thermocouple, on columns FAST-11 CF E (FAST-14 CF E) - ionization sensor. Columns with an ionization sensor have an electronic control unit that needs power supply - a 1.5 V battery. The minimum water pressure at which the burner is ignited is 0.2 bar (0.2 kgf / cm 2).
The diagram of the FAST CF model E water heater (i.e. with an ionization sensor) is shown in Fig. 28. The column consists of the following nodes:
Gas outlet (traction diverter);
Heat exchanger;
Burner;
Control block;
Gas valve;
Water valve.
The flue gas outlet is made of 0.8 mm thick sheet aluminum. The diameter of the flue pipe FAST-11 is 110 mm, FAST-14 is 125 mm (or 130 mm). A draft sensor is installed on the gas outlet 1 ... The heat exchanger of the water heater is made of copper according to the "Water cooling of the combustion chamber" technology. Copper tube has a wall thickness of 0.75 mm, an inner diameter of 13 mm. The burner model FAST-11 has 13 nozzles, FAST-14 has 16 nozzles. The nozzles are pressed into the manifold; when switching from natural gas to liquefied gas or vice versa, the entire manifold is replaced. The ionization electrode is attached to the burner 4, ignition electrode 2 and igniter 3.
Rice. 28. Diagram of the FAST CFE water heater
Electronic control unit powered by a battery with a voltage of 1.5 V. Ionization and ignition electrodes, a draft sensor, an on / off button 5, a microswitch are connected to it 6, as well as the main solenoid valve 7 and the ignition solenoid valve 8. Both solenoid valves fit into gas valve, which also has a membrane 9, main valve 10 and cone valve 11. The gas valve has a device for regulating the gas supply to the burner (12). The user can adjust the gas flow from 40 to 100% of the possible value.
The water valve has a diaphragm with a poppet 13 and Venturi tube 14. With a water temperature regulator 15 the consumer can change the water flow through the water heater from the minimum (2-5 l / min) to the maximum (11 l / min or 14 l / min, respectively). The water valve has a main regulator 16 and additional regulator 17, as well as a flow regulator 18. A vacuum tube is used to ensure the differential pressure across the diaphragm. 19.
FAST CF Model E columns are automatic, after pressing the button " on off" 5 further switching on and off is performed by the hot water tap. When the water flow through the water valve is more than 2.5 l / min, the membrane with a plate 13 moves and turns on the microswitch 6, and also opens the cone valve 11. Main valve 10 before switching on, it is closed, since the pressure above and below the membrane 9 is the same. The supra-membrane and sub-membrane spaces are interconnected through the normally open main solenoid valve 7. After switching on, the electronic control unit supplies sparks to the ignition electrode 2 and voltage to the solenoid valve of the ignition 8, which was closed. If after igniting the igniter 3 ionization electrode 4 detects a flame, the main solenoid valve is energized 10 and it closes. Membrane gas 9 goes to the igniter. Diaphragm pressure 9 decreases, it moves and opens the main valve 10. Gas goes to the burner, it ignites. Igniter 3 goes out, the power to the igniter valve is turned off. If the burner goes out, through the ionisation electrode 4 the current will stop flowing. The control unit will cut off the power to the main solenoid valve 7. It will open, the pressure below and above the diaphragm will equalize, the main valve 10 will close. The burner power is changed automatically and depends on the water consumption. Conical valve 11 due to its shape, it provides a smooth change in the amount of gas supplied to the burner.
The water valve is working in the following way. With water flow, membrane with a plate 13 deviates due to pressure changes below and above the diaphragm. The process takes place due to the Venturi tube 14. When water flows through the constriction of the venturi, the pressure decreases. Through a vacuum tube 19 the reduced pressure is transferred to the supramembrane space. Main regulator 16 connected to the membrane 13. It moves depending on the water flow, as well as the position of the additional regulator 1 7. The flow of water ends through the venturi and the open temperature controller 15. Temperature regulator 15 the consumer can change the flow of water, which allows some of the water to be supplied bypassing the venturi. The more water flows through the temperature controller 15, the lower its temperature at the outlet of the water heater.
Gas supply adjustment to the burner, depending on the flow of water, is as follows. With an increase in flow, the membrane with a plate 13 deviates. With her the main regulator deviates 16, the water flow decreases, i.e. the water flow depends on the position of the membrane. At the same time, the position of the cone valve 11 in the gas valve also depends on the movement of the diaphragm with the poppet 13.
When you close the tap hot water pressure on both sides of the membrane with a plate 13 aligns. Spring closes cone valve 11.
Traction sensor 1 installed on the gas outlet. If the thrust is violated, it is heated by the combustion products, the contact in it is opened. As a result, the control unit is disconnected from the battery, the water heater is turned off.
Review questions
1. What is the nominal pressure of LPG for household stoves?
2. What needs to be done to transfer the stove from one gas to another?
3. How is the hob crane arranged?
4. How does the electric ignition of the stove burners take place?
5. Describe the main malfunctions of the plates.
6. Explain the sequence of actions for lighting the stove burners.
7. What are the main nodes of a column?
8. What does the speaker safety automatics control?
9. How is the gas section of KGI-56 arranged?
10. How does the block crane KGI-56 work?
11. How is the water part of VPG-23 arranged?
12. Where is the Venturi nozzle in the VPG-23?
13. Describe the operation of the water section of the VPG-23.
14. How is the VPG-23 solenoid valve arranged?
15. How does the VPG-23 thrust automatics work?
16. For what reason can the main burner of the VPG-23 not light up?
17. What is the minimum water pressure for the FAST column to operate?
18. What is the supply voltage for the FAST column?
19. Describe the design of the gas valve of the FAST column.
20. Describe how the FAST column works.
