VPG 23 technical characteristics. Gas instantaneous water heaters. Review questions

The names of dispensers produced in Russia often contain the letters VPG: this is a water heating device (W), flow-through (P), gas (G). The number after the letters VPG indicates the thermal power of the device in kilowatts (kW). For example, VPG-23 is a flow-through gas water heating device with a thermal power of 23 kW. So the title modern speakers does not define their design.

The VPG-23 water heater was created on the basis of the VPG-18 water heater, produced in Leningrad. Subsequently, 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 components, for example, the water part, are used in some models of modern Neva speakers.

Basic specifications HSV-23:

thermal power— 23 kW;
productivity when heated at 45 °C - 6 l/min;
minimum water pressure - 0.5 bar:
maximum water pressure - 6 bar.

VPG-23 consists of a gas outlet, a heat exchanger, a main burner, a block valve and a solenoid valve (Fig. 74).

The gas outlet serves to supply combustion products to the smoke exhaust pipe of the column. The heat exchanger consists of a heater and a fire chamber surrounded by a coil cold water. 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 HSV columns have a heat exchanger consisting of a single heater. The walls of the fire chamber in this case were made of steel sheet, there was no coil, which allowed saving copper. The main burner is multi-nozzle, it consists of 13 sections and a manifold, connected to each other by two screws. The sections are assembled into a single unit using coupling bolts. There are 13 nozzles installed in the manifold, each of which sprays gas into its own section.

The block tap 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, and a gas valve cap. A conical insert for the gas valve plug is pressed into the housing. The valve has rubber seal by outer diameter. A cone spring presses on it from above. The safety valve seat is made in the form of a brass liner, pressed into the body of the gas part. The gas valve has a handle with a limiter that secures the opening of the gas supply to the igniter. The tap plug is pressed against the cone liner by a large spring.

The valve plug has a recess for supplying gas to the igniter. When the valve is turned from the extreme left position to an angle of 40°, the recess 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, Venturi nozzle, membrane, poppet with rod, ignition retarder, rod seal and rod pressure bushing. Water is supplied to the water part on the left, enters the submembrane space, creating a pressure in it equal to the water pressure in the water supply. Having created pressure under the membrane, the water passes 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 open into an outer circular recess. The groove coincides with the through holes that are present in both water part covers. Through these holes, pressure from the narrowest part of the Venturi nozzle will be transferred to the supra-membrane space. The poppet rod is sealed with a nut, which compresses the fluoroplastic seal.

The water flow automation works as follows. When water passes through a Venturi nozzle, the narrowest part has the highest water speed and therefore the lowest pressure. This pressure is transmitted through the through holes into the supra-membrane cavity of the water part. As a result, a pressure difference appears under and above the membrane, which bends upward and pushes the plate with the rod. The water part rod, resting against the gas part rod, lifts the valve from the seat. As a result, the gas passage to the main burner opens. When water flow stops, the pressure under and above the membrane is equalized. The cone spring presses on the valve and presses it against the seat, and the gas supply to the main burner stops.

The solenoid valve (Fig. 76) serves to shut off the gas supply when the igniter goes out.

When you press the solenoid valve button, its rod rests against the valve and moves it away from the seat, 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 tap. After the igniter is ignited, the flame begins to heat the thermocouple, the end of which is installed in a strictly defined position in relation to the igniter (Fig. 77).

The voltage generated when the thermocouple is heated is supplied to the winding of the electromagnet core. In this case, the core holds the anchor, and with it the valve, in open position. The time during which the thermocouple generates the necessary thermo-EMF and the electromagnetic valve begins to hold the armature is about 60 seconds. When the igniter goes out, the thermocouple cools down and stops producing voltage. The core no longer holds the armature; under the action of the spring, the valve closes. The gas supply to both the igniter and the main burner is stopped.

Automatic draft switches off the gas supply to the main burner and igniter if the draft in the chimney is disrupted; it works on the principle of “gas removal from the igniter.” Automatic traction control consists of a tee, which 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 traction sensor (Fig. 78) consists of a bimetallic plate and a fitting secured with two nuts. The upper nut also serves as a seat for a plug that blocks the gas outlet from the fitting. A tube supplying gas from the tee is attached to the fitting with a union nut.

With normal draft, combustion products go into the chimney without heating the bimetallic plate. The plug is pressed tightly to the seat, gas does not escape from the sensor. If the draft in the chimney is disrupted, the combustion products heat the bimetallic plate. It bends upward and opens the gas outlet from the fitting. The gas supply to the igniter decreases sharply, and the flame stops heating the thermocouple normally. It cools down and stops producing voltage. As a result, the solenoid valve closes.

Repair and service

The main malfunctions of the VPG-23 column include:

1. The main burner does not light up:

low water pressure;
deformation or rupture of the membrane - replace the membrane;
Venturi nozzle is clogged - clean the nozzle;
the rod has come off the plate - replace the rod with the plate;
misalignment of the gas part in relation to the water part - align with three screws;
the rod does not move well in the oil seal - lubricate the rod and check the tightness of the nut. If you loosen the nut more than necessary, water may leak from under the seal.

2. When the water intake stops, the main burner does not go out:

Contaminants have gotten under the safety valve - clean the seat and valve;
the cone spring is weakened - replace the spring;
the rod does not move well in the oil seal - lubricate the rod and check the tightness of the nut. When the pilot flame is present, the solenoid valve is not held open:

3. Violation electrical circuit between the thermocouple and the electromagnet (break or short circuit). Possible following reasons:

lack of contact between the thermocouple and electromagnet terminals - clean the terminals with sandpaper;
insulation failure copper wire thermocouple and short circuit it with the tube - in this case the thermocouple is replaced;
violation of the insulation of the turns of the electromagnet coil, shorting them to each other or to the core - in this case the valve is replaced;
disruption of the magnetic circuit between the armature and the core of the electromagnet coil due to oxidation, dirt, grease film, etc. It is necessary to clean the surfaces using a piece of rough cloth. Cleaning surfaces with files, sandpaper, etc. is not allowed.

4. Insufficient heating of the thermocouple:

the working end of the thermocouple is smoked - remove soot from the hot junction of the thermocouple;
the igniter nozzle is clogged - clean the nozzle;
The thermocouple is incorrectly installed relative to the igniter - install the thermocouple relative to the igniter so as to ensure sufficient heating.

The names of dispensers produced in Russia often contain the letters VPG: this is a water heating device (W), flow-through (P), gas (G). The number after the letters VPG indicates the thermal power of the device in kilowatts (kW). For example, VPG-23 is a flow-through gas water heating device with a thermal power of 23 kW. Thus, the name of modern speakers does not determine their design.

Main technical characteristics of VPG-23:

thermal power - 23 kW;
productivity when heated at 45 °C - 6 l/min;
minimum water pressure - 0.5 bar:
maximum water pressure - 6 bar.

VPG-23 consists of a gas outlet, a heat exchanger, a main burner, a block valve and a solenoid valve (Fig. 74).

The gas outlet serves to supply combustion products to the smoke exhaust pipe of the column. The heat exchanger consists of a 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 HSV columns have a heat exchanger consisting of a single heater. In this case, the walls of the fire chamber were made of steel sheet; there was no coil, which allowed saving copper. The main burner is multi-nozzle, it consists of 13 sections and a manifold, connected to each other by two screws. The sections are assembled into a single unit using coupling bolts. There are 13 nozzles installed in the manifold, each of which sprays gas into its own section.

The block tap 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, and a gas valve cap. A conical insert for the gas valve plug is pressed into the housing. The valve has a rubber seal along the outer diameter. A cone spring presses on it from above. The safety valve seat is made in the form of a brass liner, pressed into the body of the gas part. The gas valve has a handle with a limiter that secures the opening of the gas supply to the igniter. The tap plug is pressed against the cone liner by a large spring.

The solenoid valve (Fig. 76) serves to shut off the gas supply when the igniter goes out.

The voltage generated when the thermocouple is heated is supplied 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 necessary thermo-EMF and the electromagnetic valve begins to hold the armature is about 60 seconds. When the igniter goes out, the thermocouple cools down and stops producing voltage. The core no longer holds the armature; under the action of the spring, the valve closes. The gas supply to both the igniter and the main burner is stopped.

Repair and service

The main malfunctions of the VPG-23 column include:

1. The main burner does not light up:

low water pressure;
deformation or rupture of the membrane - replace the membrane;
Venturi nozzle is clogged - clean the nozzle;
the rod has come off the plate - replace the rod with the plate;
misalignment of the gas part in relation to the water part - align with three screws;
the rod does not move well in the oil seal - lubricate the rod and check the tightness of the nut. If you loosen the nut more than necessary, water may leak from under the seal.

2. When the water intake stops, the main burner does not go out:

Contaminants have gotten under the safety valve - clean the seat and valve;
the cone spring is weakened - replace the spring;
the rod does not move well in the oil seal - lubricate the rod and check the tightness of the nut. When the pilot flame is present, the solenoid valve is not held open:

3. Violation of the electrical circuit between the thermocouple and the electromagnet (break or short circuit). The following reasons are possible:

lack of contact between the thermocouple and electromagnet terminals - clean the terminals with sandpaper;
violation of the insulation of the copper wire of the thermocouple and short circuit it with the tube - in this case, the thermocouple is replaced;
violation of the insulation of the turns of the electromagnet coil, shorting them to each other or to the core - in this case the valve is replaced;
disruption of the magnetic circuit between the armature and the core of the electromagnet coil due to oxidation, dirt, grease film, etc. It is necessary to clean the surfaces using a piece of rough cloth. Cleaning surfaces with files, sandpaper, etc. is not allowed.

4. Insufficient heating of the thermocouple:

the working end of the thermocouple is smoked - remove soot from the hot junction of the thermocouple;
the igniter nozzle is clogged - clean the nozzle;
The thermocouple is incorrectly installed relative to the igniter - install the thermocouple relative to the igniter so as to ensure sufficient heating.

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These water heating devices (Table 133) (GOST 19910-74) are installed mainly in gasified residential buildings, equipped with running water, but without centralized hot water supply. They provide rapid (within 2 minutes) heating of water (up to a temperature of 45 ° C) continuously supplied from the water supply.
Based on the equipment with automatic and control devices, the devices are divided into two classes.

Table 133. TECHNICAL DATA OF DOMESTIC GAS FLOW WATER HEATING DEVICES

Note. Type 1 devices - with exhaust of combustion products into the chimney, type 2 - with exhaust of combustion products into the room.

High-end devices (B) have automatic safety and regulation devices that provide:

b) turning off the main burner in the absence of vacuum in
Chimney (apparatus type 1);
c) regulation of water flow;
d) regulation of gas flow or pressure (natural only).
All devices are equipped with an externally controlled ignition device, and type 2 devices are additionally equipped with a temperature selector.
First class devices (P) are equipped with automatic ignition devices that provide:
a) gas access to the main burner only in the presence of a pilot flame and water flow;
b) turning off the main burner in the absence of vacuum in the Chimney (type 1 device).
The pressure of heated water at the inlet is 0.05-0.6 MPa (0.5-6 kgf/cm²).
The devices must have gas and water filters.
The devices are connected to water and gas pipelines using union nuts or couplings with locknuts.
Symbol of a water heater with a rated heat load of 21 kW (18 thousand kcal/h) with combustion products discharged into the chimney, operating on gases of the 2nd category, 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); HSV-18 and HSV-25 (Table 134).

Rice. 128. Flow gas water heater HSV-18
1 - cold water pipe; 2 - gas tap; 3 - pilot burner; 4-gas exhaust device; 5 - thermocouple; 6 - solenoid valve; 7 - gas pipeline; 8 - pipe hot water; 9 - traction sensor; 10 - heat exchanger; 11 - main burner; 12 - water-gas block with nozzle

Table 134. TECHNICAL DATA OF UNIFIED FLOW FLOW WATER HEATERS VPG

Indicators	Water heater model
Indicators	HSV-8	HSV-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/m2): natural liquefied Volume of heated water in 1 min at 50 °C, l Diameter of fittings for water and gas, mm Diameter of the pipe for removal of combustion products, mm
Overall dimensions, mm;

Table 135. TECHNICAL DATA OF GAS WATER HEATERS

Indicators	Water heater model
Indicators	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/mnn, temperature 60° C	7,5	6	6	4,8
Diameter of the pipe for removal of combustion products, mm	130	125	125	128
Diameter of connecting fittings 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

Gas instantaneous water heaters

The main components 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 . Combustion products pass through a heat exchanger and are discharged into the chimney. The heat of combustion products is transferred to water flowing through the heat exchanger. A coil is used to cool the fire chamber 10 , through which the water passing through the heater circulates.

Gas instantaneous water heaters are equipped with gas exhaust devices and draft interrupters, which, in the event of a short-term loss of draft, prevent the flame from going out

gas burner device. There is a smoke outlet pipe for connection to the chimney.

Flow-through water heating devices are designed to produce hot water where it is not possible to provide it centrally (from a boiler room or heating plant), and are classified as immediate-action devices.

Rice. 12.3. Schematic diagram instantaneous water heater:

1 – reflector; 2 – top cap; 3 – lower cap; 4 – heater; 5 – igniter; 6 – casing; 7 – block crane; 8 – burner; 9 – fire chamber; 10 – coil

The devices are equipped with gas exhaust devices and draft interrupters, which prevent the flame of the gas burner device from going out in the event of a short-term loss of draft. There is a smoke outlet pipe for connection to the smoke duct.

According to the rated thermal load, the devices are divided:

With a rated thermal load of 20934 W;

With a rated thermal load of 29075 W.

The domestic industry mass-produces instantaneous gas household water heating devices VPG-20-1-3-P and VPG-23-1-3-P. The technical characteristics of the specified water heaters are given in table. 12.2. Today, new types of water heaters are being developed, but their design is close to the current ones.

All the main elements of the device are mounted in an enamel rectangular casing.

The front and side walls of the casing are removable, which creates convenient and easy access to the internal components of the device for routine inspections and repairs without removing the device from the wall.

Use instantaneous water heating gas apparatus HSV type design, which is shown in Fig. 12.4.

There is a control knob on the front wall of the device casing. gas tap, a button for turning on the solenoid valve and an observation window for observing the flame of the pilot and main burners. On top of the device there is a gas exhaust device, which serves to discharge combustion products into the chimney, and on the bottom there are pipes for connecting the device to gas and water networks.

The device has the following components: gas pipeline 1 , gas block valve 2 , pilot burner 3 , main burner 4 , cold water pipe 5 , water-gas block with burner tee 6 , heat exchanger 7 , automatic device traction safety with solenoid valve 8 , traction sensor 9 , hot water pipe 11 and gas exhaust device 12 .

The operating principle of the device is as follows. Gas through a pipe 1 enters the solenoid valve, the activation button of which is located to the right of the gas valve activation handle. The gas shut-off valve of the water-gas burner unit performs a forced sequence of turning on the pilot burner and supplying gas to the main burner. The gas valve is equipped with one handle that turns from left to right with fixation in three positions. The extreme left position corresponds to closing the gas supply to the ignition and main burners. The middle fixed position (turning the handle to the right until it stops) corresponds to the full opening of the valve to allow gas to flow to the ignition burner when the valve to the main burner is closed. The third fixed position, achieved by pressing the valve handle in the axial direction all the way and then turning it all the way to the right, corresponds to the full opening of the valve to allow gas to flow to the main and ignition burners. In addition to manually blocking the valve, there are two automatic blocking devices on the gas path to the main burner. Blocking gas flow to the main burner 4 with mandatory pilot burner operation 3 provided by a solenoid valve.

Blocking the gas supply to the burner based on the presence of water flow through the apparatus is carried out by a valve driven through a rod from a membrane located in the water-gas burner block. When the valve solenoid button is pressed and the gas blocking valve is open, gas flows through the solenoid valve into the blocking valve and then through the tee through the gas pipeline to the ignition burner. With normal draft in the chimney (the vacuum is at least 2.0 Pa). The thermocouple, heated by the pilot burner flame, transmits a pulse to the solenoid valve, which automatically opens gas access to the block valve. If the draft is disturbed or absent, the bimetallic plate of the draft sensor is heated by the escaping gas combustion products, opens the draft sensor nozzle, and the gas entering the ignition burner during normal operation of the apparatus leaves through the draft sensor nozzle. The pilot burner flame goes out, the thermocouple cools, and the solenoid valve turns off (within 60 s), i.e., it stops the gas supply to the apparatus. To ensure smooth ignition of the main burner, an ignition retarder is provided, which operates when water flows out of the over-membrane cavity as check valve, partially blocking the valve cross-section and thereby slowing down the upward movement of the membrane, and, consequently, the ignition of the main burner.

Table 12.2

Technical characteristics of instantaneous gas water heaters

Characteristic	Water heater brand
VPG-T-3-P I	VPG-20-1-3-P I	VPG-231	VPG-25-1-3-V
Thermal power of the main burner, kW	20,93	23,26	23,26	29,075
Nominal gas consumption, m 3 /h: natural liquefied	2,34-1,81 0,87-0,67	2,58-2,12 0,96-0,78	2,94 0,87	no more than 2.94 no more than 1.19

Water consumption when heated to 45 °C, l/min, not less	5,4	6,1	7,0	7,6
Water pressure in front of the apparatus, MPa: minimum nominal maximum	0,049 0,150 0,590	0,049 0,150 0,590	0,060 0,150 0,600	0,049 0,150 0,590
Vacuum in the chimney for normal operation of the device, Pa
Dimensions of the device: m: height width depth
Device weight: kg, no more			15,5

The highest class includes the instantaneous water heating apparatus VPG-25-1-3-V (Table 12.2). It manages all processes automatically. This ensures: gas access to the ignition burner only if there is a flame and water flow on it; stopping the gas supply to the main and ignition burners in the absence of vacuum in the chimney; gas pressure (flow) regulation; regulation of water flow; automatic ignition of the pilot burner. Capacitive water heaters AGV-80 (Fig. 12.5) are still widely used, consisting of a sheet steel tank, a burner with an igniter and automation devices (solenoid valve with thermocouple and thermostat). A thermometer is installed at the top of the water heater to monitor the water temperature.

Rice. 12.5. Automatic gas water heater AGV-80

1 – traction breaker; 2 – thermometer coupling; 3 – automatic traction safety unit;

4 – stabilizer; 5 – filter; 6 – magnetic valve; 7– - thermostat; 8 – gas tap; 9 – pilot burner; 10 – thermocouple; 11 – flap; 12 – diffuser; 13 – main burner; 14 – cold water supply fitting; 15 – tank; 16 – thermal insulation;

17 – casing; 18 – pipe; for hot water outlet to apartment wiring;

19 – safety valve

The safety element is a solenoid valve 6 . Gas entering the valve body from the gas pipeline through the tap 8 , lighting the pilot 9 , heats the thermocouple and goes to the main burner 13 , on which the gas is ignited from the igniter.

Table 12.3

Technical characteristics of gas water heaters

with water circuit

Characteristic	Water heater brand
AOGV-6-3-U	AOGV-10-3-U	AOGV-20-3-U	AOGV-20-1-U
Dimensions, mm: diameter height width depth	– –	– –	–	– –
Area of the heated room, m2, no more				80–150
Rated thermal power of the main burner, W
Nominal thermal power of the pilot burner, W
Water temperature at the outlet of the apparatus ͵ °С	50–90	50–90	50–90	50–90
Minimum vacuum in the chimney, Pa
Temperature of combustion products at the outlet of the apparatus, °C, not less
Connection pipe thread fittings, inch: for supplying and discharging water for gas supply	1 ½ 1 ½	1 ½ 1 ½	¾	¾
Efficiency, %, not less

The automatic gas water heater AGV-120 is designed for local hot water supply and heating of premises with an area of up to 100 m2. The water heater is a vertical cylindrical tank with a capacity of 120 liters, enclosed in a steel casing. A cast iron injection system is installed in the combustion part gas-burner low pressure, to which a bracket with an igniter is attached. Gas combustion and maintaining a certain water temperature are automatically regulated.

Scheme automatic regulation two-position. The main elements of the automatic control and safety unit are a bellows thermostat, an igniter, a thermocouple and a solenoid valve.

Water heaters with a water circuit of the AOGV type operate on natural gas, propane, butane and their mixtures.

Rice. 12.6. Gas heating device AOGV-15-1-U:

1 – thermostat; 2 – traction sensor; 3 – shut-off and control valve;

4 – shut-off valve; 5 – pilot burner fitting; 6 – filter;

7 – thermometer; 8 – direct (hot) water supply fitting; 9 – connecting tube (common); 10 – tee; 11 – connecting tube of the draft sensor; 12 – impulse pipeline of the ignition burner; 13 - safety valve; 14 – connecting tube of the flame extinction sensor; 15 – mounting bolt; 16 – asbestos gasket; 17 – cladding; 18 – flame extinction sensor; 19 – collector; 20 – gas pipeline

Devices of the AOGV type, unlike capacitive water heaters, are used only for heating.

The AOGV-15-1-U device (Fig. 12.6), made in the form of a rectangular cabinet with a white enamel coating, consists of a heat exchanger boiler, a smoke exhaust pipe with an adjustable damper as a draft stabilizer, a casing, a gas burner device and an automatic control and safety unit.

Gas from filter 6 enters the shut-off valve 4 , from which there are three exits:

1) main – on the shut-off and control valve 3 ;

2) to the fitting 5 top cover for supplying gas to the pilot burner;

3) to the fitting of the bottom cover for supplying gas to the draft sensors 2 and the flame goes out 18 ;

Through the shut-off valve, gas enters the thermostat 1 and via gas pipeline 20 to the collector 19 , from where it is supplied through two nozzles to the confuser of burner nozzles, where it is mixed with primary air, and then sent to the combustion space.

Rice. 12.7. Burners vertical ( A) and adjustable with horizontal

tubular mixer ( b):

1 – cap; 2 – fire nozzle; 3 – diffuser; 4 – gate; 5 – nozzle nipple;

6 – nozzle body; 7 – threaded bushing; 8 – mixing tube; 9 – mixer mouthpiece

Gas instantaneous water heaters - concept and types. Classification and features of the category "Gas instantaneous water heaters" 2017, 2018.

The main components of an instantaneous water heater (Fig. 12.3) are: a gas burner device, a heat exchanger, an automation system and a gas outlet.

Low pressure gas is supplied to the injection burner 8 . Combustion products pass through a heat exchanger and are discharged into the chimney. The heat of combustion products is transferred to water flowing through the heat exchanger. A coil is used to cool the fire chamber 10 , through which the water passing through the heater circulates.

Gas instantaneous water heaters are equipped with gas exhaust devices and draft interrupters, which, in the event of a short-term loss of draft, prevent the flame from going out

gas burner device. There is a smoke outlet pipe for connection to the chimney.

Rice. 12.3. Schematic diagram of an instantaneous water heater:

1 – reflector; 2 – top cap; 3 – lower cap; 4 – heater; 5 – igniter; 6 – casing; 7 – block crane; 8 – burner; 9 – fire chamber; 10 – coil

According to the rated thermal load, the devices are divided:

With a rated thermal load of 20934 W;

With a rated thermal load of 29075 W.

The domestic industry mass-produces instantaneous gas household water heating devices 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 those currently in use.

All the main elements of the device are mounted in an enamel rectangular casing.

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 apparatus casing there is a gas valve control handle, a button for turning on the solenoid valve and an observation window for observing the flame of the ignition and main burners. On top of the device there is a gas exhaust device, which serves to discharge combustion products into the chimney, and on the bottom there are pipes for connecting the device to gas and water networks.

Repair and service

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