Heating system for VAZ 2115, its design and repair

Operating principle and design of the VAZ-2115 heating system

If the heater in the car does not work, especially in the cold season, there is a possibility of being left without a means of transportation, since in the cold you can simply freeze inside the car. In severe frosts, it is very difficult to clear the windshield of ice to ensure visibility, and with a non-working stove this becomes doubly problematic. You may not even be able to get to a service station.

But most often, if you know the operating principle, circuit and design of the VAZ-2115 stove, you can solve the problem on the spot yourself.

Changing the cabin filter of a VAZ 2114

The air inside the cabin without using a filter will be filled with road dust and exhaust gases; it is clear that this will negatively affect the health of the driver and passengers. The immediate function of a car filter is to purify the air entering the cabin. As a result, it is susceptible to rapid contamination, and there is absolutely no benefit from such a filter. It only makes it difficult for air to get to the heater. For this reason, the filter must be replaced. This procedure is available for DIY replacement. First, dismantle the brush holders and the windshield wiper system, then remove the grille (plastic). After this, the nuts securing the plastic cover are removed, resulting in a small hole being freed. The filter is not attached to anything, so there should not be any problems in removing it, and replace it with a new one in the same way. All parts are mounted in place.

Conclusion

The procedure for replacing a VAZ 2114 stove is quite simple. The main point is the timely replacement of pipes and clamps if they are not suitable for further use.

After carrying out repair or maintenance work, do not forget to refill the system with coolant.

At the end of the work, when you start the engine, the stove should cope with the heating function perfectly. If the opposite happens, there is most likely an air lock.

During repairs, the vehicle must be kept on the handbrake. If the car was running before starting repair work, then the radiator will be very hot, so wait a little.

If you understand that you cannot cope with this work, please contact the service department.

Construction of the VAZ-2115 heating system

The electrical diagram of the VAZ heater operation is represented by the following elements:

• Electric motor with fan. The fan drives hot air into the car interior and onto the windshield.
• Buttons and levers for switching heat level and air flow speed. The VAZ-2115 has 3 options for heat flow rates that can be adjusted.
• Additional resistances that provide the required rotation speed of the stove fan (step-down tungsten turn coils).
• Fuses and connection wires.

The diagram of the VAZ-2115 stove presented below clearly shows its operating structure and components.

Heater fan diagram for VAZ 2114, 2115, 2113.

And so, here is a list of all components of the scheme:

1. Mounting block (aka fuse block).
2. Egnition lock.
3. Ignition switch relief relay.
4. Heater fan speed switch.
5. Additional resistors.
6. Stove motor.
7. Rear window heating switch with warning lamp.
8. Rear window heating element.

The scheme works as follows. When you turn the key in the ignition switch (2), its unloading relay (3) is turned on. The unloading relay supplies power to fuse f7 in the mounting block (1). After the fuse, power goes to the rear window heating switch (7) and the fan speed switch (4), which distributes which of the resistors (5) the power will go to next. Output 1 from the switch (4) corresponds to the slowest blowing speed, and output 3 goes directly to the heater motor (6), i.e. highest blowing speed.

The operation of the stove is based on the following principle

The cooling and heating system works the same on almost all VAZ car models. The heater is turned on using a regulator located in the car itself; antifreeze is supplied to the radiator. Its temperature after warming up reaches more than 80 degrees. After which the fan starts working, operating at one of 3 speed modes.

The fan begins to create a directed air flow. It moves from the outside of the heating system into the interior of the car. Using control flaps, the driver selects heating zones, there are three in total: on the feet, on the windshield and in the car interior.

The key element of a car's heating system is the fan, and if it fails, the heating will be lost. Without it, hot air will not enter the cabin, and to heat the interior of the VAZ-2115, it will take not a couple of minutes, but a couple of hours.

Why the stove does not work or does not heat the air

If the stove fails, it either does not work at all, or it works but does not heat the air. In the first case, first check the fan wiring, starting with fuse F7. If the fuse is blown, replace it. Then they check the relay, which may not turn on the first time or only when the engine is warm. In this case, the relay is replaced with a new one.

Then the serviceability of the electric motor is assessed. To do this, power is directly supplied to its contacts from the battery. If the electric motor starts to operate at maximum speed, then it is in good condition. Otherwise, it will need to be repaired or replaced.

The intensity of the air flow is adjusted using a resistor having two spirals with resistances of 0.82 Ohm and 0.23 Ohm. In the first mode, the current flows through both spirals, in the second - only through a spiral with a resistance of 0.23 Ohms, in the third - bypassing the spirals, that is, without resistance at all. If the resistor is faulty, the fan will only operate in the third mode at maximum speed (handle in the extreme right position). The problem is solved by replacing the resistor, which is located on the driver's side above the accelerator pedal.

If the resistor is faulty, the heater fan will only be able to operate at maximum speed.

If cold air enters the cabin, this may be due to:

• Airlock. It could have formed when replacing the coolant, when the system was depressurized, or because there was insufficient amount of coolant in the system. To remove the plug, remove the heater radiator pipe, use a watering can to add antifreeze to the maximum and put the hose back in place. After starting the engine, coolant under pressure will displace the remaining air from the system.
• Stove tap jammed. This happens if the tap was not initially opened all the way, and during operation, oxide and scale formed on the inner surface, preventing the normal circulation of the liquid. You can try to open the tap using pliers or immediately replace it with a new one.
• The stove radiator is clogged. When using low-quality coolant, the radiator honeycombs may become clogged. The problem is solved by flushing or replacing the heat exchanger. The feasibility of washing is determined by the scale of contamination.
• Installation of a low-quality radiator. In a defective product, the honeycomb may be incorrectly soldered. The radiator should be replaced.
• Low pressure in the cooling system. If heat transfer increases at higher speeds, the pump needs to be replaced.
• Low coolant level. It is necessary to check the level and add antifreeze if necessary.
• Damage to the heater fan impeller. The impeller is carefully inspected and replaced if mechanical damage is detected.
• Cabin filter dirty. If it is heavily polluted, the power of the electric motor will not be enough to pump warm air into the cabin. The filter is replaced with a new one.
• Damage to the cylinder head gasket. If the cylinder head gasket is blown, white smoke will come out of the exhaust pipe. The problem is solved by replacing the gasket and dismantling the cylinder head.

If the stove is clogged, warm air will stop flowing into the cabin.

Major electrical failures of the heating system of the VAZ-2115

If no changes occur in the heating system at any position of the switch knob, then most likely the system motor is faulty (the brushes are worn out) or there is no voltage at the terminals. But also in this case there may be problems with the ignition switch or mounting block (fuse F4 has blown).

It is important for the proper operation of the car's heating system that there is no more than 3 ohms at the engine ground (installed under the hood).

If the heater works normally at maximum engine speeds, and problems arise only at low speeds, then the cause of the malfunction most likely lies in the speed switch button or additional resistors.

If you turn on the interior heating system and hear a noise and the heater is not blowing properly, this also indicates an engine problem. Malfunctions may include jamming of the impeller or armature bearings. Malfunctions can be eliminated by replacing components or, if necessary, lubricating them. But, as a rule, these actions have a short-term effect and the problem returns.

Over time, any equipment breaks down and requires repair. Therefore, the heating system is no exception here, and the least that needs to be done for preventive purposes is to at least carry out periodic visual inspections and diagnostics. Don’t forget that over time the system ages and wears out, so the older the car, the more it needs to be prepared for the heating season.

Why is antifreeze leaking from the stove?

A coolant leak in the heating system can occur from:

1. stove radiator;
2. stove tap;
3. stove pipes.

If a coolant leak occurs from the radiator, it is usually replaced with a new one. Repairs to restore tightness are usually complex and labor-intensive. In addition, if the radiator has been in use for a long time, its tubes become clogged with deposits and dirt, and, as a result, heat transfer decreases.

The valve opens and closes the coolant supply to the radiator, thereby regulating the heat in the cabin. Over time, it may begin to leak, as evidenced by the characteristic smell of antifreeze in the cabin, a puddle on the floor on the passenger side and a decrease in the coolant level in the expansion tank. The faucet cannot be repaired and in such cases is replaced entirely.

If the heater radiator starts to leak, it is usually replaced with a new one.

The cause of coolant leakage from the pipes is usually their wear - the rubber ages and cracks over time. When diagnosing a problem, you need to wipe the suspected leak areas with a rag and observe the outlet and inlet pipes on a warm engine. Worn hoses are always replaced with new ones.

The stove makes a hum, whistle, murmur

The cause of uncharacteristic sounds (whistle, hum, murmur, etc.) from the heater is usually a faulty electric motor. Lack of lubrication, contamination, wear of bearings and bushings - all this leads to the fact that the motor begins to whistle. It is removed, disassembled and cleaned, and the rubbing elements are lubricated. If the bearings are heavily worn, the motor will not make a whistle, but a hum. In such a situation, lubricant may not help, and the electric motor will need to be replaced.

Steam is coming from the stove

Sometimes steam starts coming out of the stove. The reason for this is a leak in the heater core. The leaking coolant hits the hot radiator housing and begins to quickly evaporate, and the smell of antifreeze appears in the cabin. To fix the problem, you will need to disassemble the stove and replace the heat exchanger.

Sometimes white steam comes from under the hood and enters the cabin. This happens when antifreeze gets on the hot manifold or exhaust system pants. In this case, you will need to find the location of the leak and fix it. The most common cause is damaged pipes.

Lada 2115 Comfort › Logbook › Modernization of the heating system (stove)

Hi all. Happy upcoming Defender of the Fatherland Day to everyone.

In general, one point in the operation of the stove bothered me: even when the lever for adjusting the supply of hot-cold air (hereinafter simply the GC lever) is in the extreme right position, COLD air was always blowing on the windshield and especially on the side windows

, despite the fact that the breath was already hot at my feet.

Let's figure out why this happens:

You can call this some kind of miscalculation of engineers. Also, due to this design, the flow temperature is poorly regulated. As you already understood from the picture, if you move the GC lever a little, cold air will immediately blow into your face, and not diluted with hot air. I think almost everyone has encountered this.