A few suitable materials
There are several options for suitable materials to create the blades and cone for the fan:
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Plastic base. It is a favorite material for constructors to make devices like fans. Plastic blades are made from the top of the bottle, which is closer to the neck. The whole part up to the cork is cut off. In addition, a cone and a base for the fan are made from the plastic bottle. The second part is usually constructed from the bottom of a plastic bottle. Sometimes additional parts are needed: beverage tubes or cardboard.
Cooler as part of the cone and blades for the fan
The fan will not turn to the sides
How to repair a floor fan if it will not side turn (pivot)? It’s all about the crank, the fixing screws of which can come loose or come out. To find out, you need to disassemble the motor housing. If the rotation of the housing is delayed or comes to a complete stop while the unit is running, check the gears in the gearbox for engagement. It is also necessary to check the gearbox switch itself, namely its movement up and down.
Disassemble the gearbox and remove the main gear. The shaft will also have to be pulled. Grease all moving parts and reassemble the Geareducer. If the gears are badly worn, they need to be replaced, although it is difficult to find analogues of broken parts for the fan. In this case, you will have to assemble the unit without the reducer and use the cooler in the normal mode, when the air masses will move in the same direction.
Fan Troubleshooting and Repair Methods
To reduce production costs and to achieve low noise level during the operation the electric motors of fans are fitted with slide bearings. As a result, after a couple of years of operation, the lubricant wears out and this is the most common cause of fan failures.
| External manifestation of the malfunction | Possible cause | Troubleshooting | How to repair |
| Fan switches off and then back on after a short period of time after normal operation | Self resetting thermal fuse from overheating of the windings tripped | Check the impeller for freedom of rotation, disassemble the fan and inspect the stator windings for blackening | Lubricate the bearings, rewind the winding |
| The fan turns on, but the blades rotate slowly | The grease in the electric motor bearings has thickened or worn out | If bearings are not well lubricated, fan will make a lot of noise when running and may smell like burnt-out because of overheated motor windings | The fan must be disassembled and the slide bearings lubricated with machine oil |
| Mechanical wear of motor bearings due to lack of lubrication. In this case it is often observed that the impeller vibrates relative to the center of rotation | Swing the impeller centrally to the sides. If the play is more than 0,5 mm, then the bearing is worn | Replace the bearing with a new one | |
| Fan doesn’t start, blades don’t rotate | The cord is not inserted into the socket | Check | Plug cord into socket |
| No voltage in the socket | Check voltage at the outlet using a working electrical appliance | Connect the fan to a working socket | |
| Power cord is defective | Check the plug and cord for mechanical damage with the external examination, check the continuity of the wires of the cord with a multimeter | If defective, replace the power plug or cord | |
| Switch or speed switch is defective. Low battery in control panel | It is necessary to open the fan and multimeter test the switch. When switched on, the resistance between the contacts of the switch should be zero | If switch is defective, replace it. If you have no handy, you can short out the contacts of the switch, and turn off the fan by pulling the plug out of the socket | |
| Fan heats up and hums when switched on | Rotor shaft is jammed due to grease leakage or thickening | Disassemble the fan, wash with solvent and lubricate the bearings | |
| Fan is humming and heating when switched on | Winding or capacitor breakage. | Turn the impeller by hand, if it rotates, then replace the capacitor or try to find the place of breakage of the starting winding | |
| Rotor winding breakage | Check the windings for mechanical damage and local darkening, check the integrity of the windings with a multimeter | If you can not find the winding breakage by external examination, you will have to rewind it, which is not economically feasible | |
| The thermal fuse has tripped due to overheating of the electric motor | Use a multimeter to check the continuity of the thermal fuse. Its resistance should be equal to zero. To check in the absence of the device its outputs can be short-circuited temporarily | If a thermal fuse breakage is found, it can be replaced with the proper one. If a new fuse blows again after a short period of fan operation, the motor is defective |
For reliable operation of the fan it is recommended before each season of operation to disassemble it and lubricate the bearings with machine oil. But nobody does it, including me. Usually, lubrication is performed when the blades stop rotating or the fan starts to make a lot of noise.
How to Grease a Cooler
Before applying graphite grease to the cooler bearing surfaces, use a cloth dampened with any solvent to remove old grease and bearing wear products, especially carefully from the bearing bush hole. a thin film of fresh graphite grease is applied to the rubbing parts of the cooler bearing and the cooler is assembled in the reverse order.
If the label is torn or won’t stick, it’s likely that grease has gotten on the surface of the cooler housing. You need to remove it with a solvent. If the label is torn or the adhesive layer has lost its adhesive properties, you can replace it with duct tape to protect the bearing from dust.
Graphite itself is a lubricant because its crystals are flakey and cover the surface very densely. The oil serves more of a bonding function to the graphite. Self-administered graphite grease applied to worn bearing surfaces in combination with synthetic machining oil and graphite provides long life of the cooler without replacement or maintenance.
From the screw or how the cooling fan impeller came to be
I am driving through Kyiv and at the crossroads I heard an unpleasant sound under the car like something caught underneath. I passed a traffic light and stopped on the right side, looked under the car and drove on without finding anything. There was an unpleasant feeling of unbalanced engine, but then about 100 meters later again crunched in front of the bottom of the car. I stopped on the curb, opened the hood and looking closely saw fragments of black plastic, as it turned out was broken into small pieces of cooling fan (fan itself) which is screwed to the temp. Apparently the first time I heard the noise the first part of the impeller came off and there was a slight imbalance of the engine, but the second time all the fan blades had already crumbled. From the shock a little bit battered honeycomb radiator, but thank God it did not break and I was able to drive home and then to the service station without any problems. Called a friend and he told me that he had a similar situation, but it was much worse, he had failed engine mount and apparently began to rattle so that the fan hit the radiator, the impeller broke and punctured the radiator. But I had no engine vibration at all after the fan blew out. Master at the service station looked and said that the cushions of the engine at me all is normal, it’s just struck the fan from old age, mileage on the car 337 000 km and it’s even if you believe that there in Germany it is not twisted swindlers. I also saw on the way to the car that the temperature sensor sometimes lies, the temperature drops and then rises to normal operation and reported this to the master service station. He says let’s change the thermostat, most likely a glitch in the thermostat. I went to a friend at the company and ordered a fan, but unfortunately the next day brought the wrong fan and had to take it back. At the disassembly are asking 20 for a new fan manufactured in Taiwan and the same amount for a second-hand original fan. I took no chances with the new Taiwan and used the original, and checked with the offices of the cost and availability of spare parts, the original thermostat is about 760grn (
79,60 ). Took the original fan (as it turned out Prospect of Italy) at a discount of 1004grn (
72), when removing the remainder of the old fan it turned out that he was installed from the factory in 1997godu and pr-va Italy. Not bad he went (the fan) for 17 years, not sorry I took the original, you could look even cheaper original, but no time to search and cars need to go, good thing there is a second car wife so without wheels did not stay. Immediately decided to replace the thermostat, but the thermostat found cheaper (though not original), the manufacturer said a good, the price was 146grn (
In the end, the repair (replacement cooling fan and thermostat) cost was 400 uah (
Repair of floor fan with his hands. All the reasons why it does not spin and how to disassemble.
On the hottest summer days, the only salvation from the sweltering heat is an ordinary floor fan.
Not everyone can afford a full-fledged split system or even a mobile conditioner.
But unfortunately, even this inexpensive and accessible fan, from time to time breaks down. Especially Chinese models fly like a cartridge.
And they are in our market in overwhelming majority. What to do if the fan stopped rotating and working? What are its main weaknesses and why does it break down??
There are 5 main causes of failure of floor fans:
How To Fix A Broken Ceiling Fan Blade
The main problem of cheap models, which for some reason not many people pay attention to. Incorrect molding of the blades. Because of this there is imbalance, broken bearings, increased clearances.
You can not influence it in any way, because you have already bought a fan with such initial defect. Sometimes it seems to work, the impeller rotates normally, but it does not blow.
That is, there is no cooling airflow from it. Why is this happening??
Because of the wrong angle of attack of the blades. Its blades are deformed and send the air flow in a circle and not outside.
This effect can appear over time, after the fan was standing for a long time in direct sunlight and its impeller heated up, began to gradually change its shape.
This can only be cured by replacing the impeller with a new one.
The most common problem is a dry lubricant or lack of it. The fan begins to cramp, losing speed and as a consequence, the load on the engine increases. The blower no longer operates at its full capacity.
The motor winded with a thin wire of 0.2 mm begins to heat up and the winding gradually burns out.
How this defect can be detected? In this case, the fan stops rotating. It hums, but the impeller does not rotate.
it may start only in the 3rd speed, and does not react to the first two. It just doesn’t have enough power to turn the shaft.
In order to start it, you have to unscrew the blades like on old planes.
By the way, the same symptom can be caused by a damaged starting capacitor. How can you know without instrumentation what is the cause of the failure??
To do this you should at least get to the motor shaft by removing the protective shroud and blades. If the shaft rotates with great difficulty by hand, then blame dirt and dried grease.
If it spins easily and has inertia, it’s probably got a busted capacitor. The symptom is. You have plugged in the fan, but it does not rotate. You crank it up and it starts.
If you hold the fan blades with your hand while running, the fan can stop again. Check the capacitor with a multimeter, if it has the appropriate capacitance scale.
To replace the condenser choose a new one with the same parameters as on the case of the old one.
By the way, a condenser that hasn’t completely dried out also affects the speed. If you notice that they have fallen and the fan began to spin slower, it’s a bell to check it.
The problem of tight rotation is solved by new bearing grease. So-called plain bearings are used here. Some people call them bushings.
It is expensive to use balls in such constructions, and they rattle a lot with time. It is not necessary to completely dismantle the motor for repair. It is enough to unscrew several screws and spray WD40 universal spray in necessary places.
How to get to the bushings without removing the engine? First, unscrew the center screw on the back of the protective cover.
One more self-tapping screw is hidden in the adjusting button-lever for turning or stopping the fan head.
Then the back cover can be easily removed from its place. What’s underneath? Here you can see the swivel gearbox, which gives the whole head rotation.
How to repair a broken box fan when a blade breaks off
There is a special rod underneath.
The motor starter capacitor is mounted on top.
Note that it might not be there in some models. In this case, look for it near the gearshift buttons.
You have to remove the gearbox to gain access to the motor bearing. It’s got three screws and a linkage at the bottom.
You remove the screws and disconnect the tie rod. Once you remove the gearbox from the shaft, you get access to the back bushing.
There is no need to unscrew and dismantle anything else. WD40 will do the rest.
Put on the WD40 spray bottle and spray a few times in the gap between the shaft and the bearing.
After you spray it with WD40, turn the shaft by hand in different directions and move it back and forth a bit.
Excessive grease, debris and dust will gradually escape. This excess dirt can easily be removed with a cotton swab.
If you have a thick grease like Tsiatim or Lithol, it is advisable to apply it to the gear worm. After these cleaning procedures, drop a few drops of sewing machine oil on the outside of the bearing.
Just don’t put too much of it on. Otherwise it gets all over the place and the dust sticks to it and turns back into dirt. You end up with a wedge and a fan rotation problem again.
some models have felt washers around the bushings. They get soaked in oil and when they get hot, the oil will drip onto the shaft, lubricating it.
Reassemble in reverse order. Puller. the three screws on the gearbox. outer cover.
By the way, if you overtighten the central screw on the back cover, which is a screw, not a screw, it can go through the plastic of the swivel gear and catch on the shaft.
Done with the rear bearing, now move on to the front of the fan. There’s a protective cap in the middle.
It unscrews, pay attention. clockwise, because the thread here is left.
You take it off and remove the propeller from the shaft. You now have access to the front plain bearing.
The principle is the same. First squeeze out and soften the old grease and dirt with a little vedishka, then apply new grease.
Then put the propeller back on and close the cap. Having finished the repair turn on the fan at high revolutions, and having worked so some minutes switch it to that speed which is required.
If the damage is more complicated and simple lubrication does not help, you have to take apart the fan in detail.
First do all the manipulations of the disassembly as above. After removing the propeller, unscrew the plastic front locknut, which is located right behind it, and remove the whole protective frame.
In your hands you are left with the motor itself and the foot where the power wires run and the push-button mechanism is located.
Disassemble this leg by unscrewing the 6 self-tapping screws.
First of all check the soldering of the wires. It is quite possible that one of them, or even some of them are broken off or burnt out.
If everything is intact, how to figure out which wire goes where and what is responsible for? Start checking with the two wires from the power plug.
One of them, let it be black (like on the photo below), through the light bulb goes directly to the motor of fan.
The second wire goes to the lower terminal of the dial switch (the 0 button).
Then, by pressing the appropriate buttons. 1st speed, 2nd, 3rd, one or the other contacts of the switch are closed, and thus the speed of the motor is changed.
Each wire from these buttons goes to a different terminal on the winding, with more or fewer turns. Applying voltage to them, you make the propeller spin faster or slower.
A simplified diagram of the windblower looks like this.
Typical diagrams for most inexpensive 3 speed floor fans are about this:
Each press of the button is followed by the closure of its own contact group.
At the same time the other contact group opens.
Sometimes these pins get burned out or don’t reach their plate. Then you are missing any of the speeds.
This is checked all elementary with a Chinese multimeter, in the circuit check mode.
If you break the very first wire or no contact, the fan motor will not start. Therefore, if the fan is completely out of order, check it first of all.
Unless, of course, you make sure that the plug itself and the power cord from it are intact. This is also called a tester.
Place one end of the probe on the plug pin and touch the other end to the contact area on the “0” button. If it’s working, there should be zero resistance.
Then you can check the wires at all speeds in the same way. The contact dipstick on the plug. the other dipstick on the offending wire from the corresponding speed button to the motor.
If there are zeros everywhere, then your switch and wires are working.
Next, check the second contact on the plug and the wire that goes directly past the switch to the motor. Make sure you have an intact cord here as well.
Only then can you proceed to check the windings of the motor itself.
Use a multimeter to set the resistance to 2,000 ohms. Further, in order not to bite out anywhere wires, in the place where the capacitor is connected, strip a little insulation.
Look for a common point in the circuit, as in the diagram below.
Once you’ve found it, call the winding resistance. To do this, touch the contacts on the switch alternately with the second probe.
The approximate resistance values of the fan windings may be as follows:
Of course this may vary slightly from model to model, but the most important thing is that there is no breakage or short circuit. Measurements can show a few hundred ohms or a little over 1k ohms.
All depends on the fan power and wire section.
The resistance between the winding leads will be less. 100-200 Ohm.
Also check the capacitor winding and the total resistance of all windings together.
Here is the most competent and complete video on how to check the functionality of the fan windings with a multimeter.
If checking the integrity of the windings also does not reveal deviations and defects, go further. To do this completely disassemble the fan, what is called in the bones.
First remove all plastic parts from the motor. Remove the 4 screws from the front side and remove the cover.
On new models besides screws there are also latches. They must be bent with a screwdriver.
To disconnect the leg, you need to find another screw, which is usually hidden under the plug.
Loosen it and pull out the mounting shaft. To remove the wires that go through the leg, you will need to bite out or solder them out from the terminal blocks on the speed buttons.
At the same time, write down or sketch which one is initially plugged in.
As a result you should have in your hands a bare fan motor without anything else.
Take it apart. Remove the screws tightening the back cover.
In this case, before disassembly, be sure to put marks on all the covers and iron, as everything was assembled originally.
Otherwise, after a misalignment, you will lose alignment. There will be problems with jamming of shaft and rotation of blades.
Remove the bearing to get to the windings themselves. Among the bundle of power wires coming from the switch, look for a special thermostat.
Very often the motor stops working after it burns out. This relay should trip and open the circuit, at a winding temperature of 135-145 degrees.
After it cools down, the relay closes again and the fan starts. So, sometimes it burns out completely and actually plays the role of a fuse.
If your fan often shuts down and starts up again, this protection is to blame. Just know that it doesn’t work like that. That means you either have a jammed shaft or the windings are coming to an end and overheating.
Overheating of the windings can be caused by a destroyed small impeller that sits on the shaft inside the motor itself. It is designed to blow off and reduce the temperature of the windings.
The cheapest models don’t have a temperature sensor-relay but are wired directly to the motor. With that in mind, if your “thermal fuse” is blown, you can of course bypass it and start the windblower. But you’re left with no fire protection.
There should be a wire circle between its tabs.
If all parts and relays inside are intact, it is only necessary to examine the winding, shaft and rotor through a magnifying glass. You will probably see some torn or chipped copper wires.
It happens when the bearing pops out of its seat and the rotor starts beating on the windings.
At modern Chinese floor fans, quite often the screw connection between the two halves of the motor loosens. Do not forget that the shaft on both sides, put on self-centering copper-graphite bushings that are tightly locked in the caps.
When assembling and tightening them, you can lightly tap the transformer iron itself with a hammer so that the shaft rotates easily, with little inertia. Someone is trying to catch the center by himself and makes this silent horror.
Eventually, the shaft falls out of the bearing, resulting in a wedge. As a consequence, the rotor begins to scratch the windings and its surface.
Also keep in mind that if your fan fell and then stopped working and rotating, it is also likely that the bushings are misaligned. Nothing else can break from such a fall.
Capacitor will not be damaged, lacquer coils will not break. Except that some of the buttons may come off. But first check the alignment of the bearings. And then everything will work as it should.
Unfortunately, a mechanical defect in the windings or rotor, as well as their intra-rotor short circuits, you can’t handle on your own. It is not rational to rewind the motors of cheap blowers, it is much easier to buy a new model.
But this is the last stage of the check, and there is hope that you will never get to it, having found the damage somewhere else, by the methods discussed above.
Tabletop Fan Repair
If you don’t have air conditioning, then in the heat the only means of providing some coolness will be an electric fan. Desktop fans are relatively simple and reliable electrical appliances.But moving parts are subject to natural wear and tear and, like many portable appliances, fans are often damaged by rough handling.
There are similar fans with a floor stand.
Let’s “Restore”: Fractal Design Dynamic GP-14 Fan (Broken Fan Blade)
How it works
The fan is usually mounted on the shaft, which rotates the electric motor. At the opposite end of the shaft there is a worm gearing connected by a gearbox to a crank which makes the fan turn slowly from side to side so the airflow covers a larger area. There is a special switch that can disengage the gearbox when the swivel mode is not needed. All but the simplest models have two speeds. The diameter of the average table fan can be between 175-300 mm, the floor models are slightly larger.
Some table fans are so cheap that it hardly makes sense to give them out for repair, but since fans tend to be very easy to maintain, it’s worth spending a little time to get the unit back in working order.
- Fan blade
- Guard rail
- Fence grille fixing screw
- Shaft
- Electric motor
- Worm gear
- Gearbox
- Gear selector switch
- Crank
- Rotation speed switch
- Contact Pad
- Clamping Plate
The fan is noisy
Deformed blades
Plastic monoblock fan propeller may be deformed near high temperature source. Deformed blades can catch on the wire guardrail, causing noise and eventually damage to both the blades and the guardrail.
Deformed guard
If the fan falls on or off the table onto the floor, the wire guard grill can become deformed and catch and possibly even damage the blades. Your fan guard may have a slightly different attachment than described here.
- The front of the fence is easily removed after loosening a single fixing screw.
- If the back of the guardrail is damaged, pull the propeller off its shaft to gain access to the large plastic nut on the back. Unscrew this nut by hand and remove the guardrail.
- Use your thumbs to loosen the wire guard and reassemble the unit in the reverse order of disassembly. There may be protrusions and notches there that will help you assemble the two halves of the guard correctly.
Fan does not turn sideways
Crank comes loose
Disassemble the case and check to see if the screws holding the crank are loose or have come loose.
- To remove the rear cover, first release all visible fasteners. You may have to squeeze the edges of the enclosure to disengage the internal latches molded together with the enclosure.
- Check that the metal crank is connected to the plastic gear wheel under the gearbox.
- Look for the missing screw inside the cover you just removed. Reattach the crank and put the cover back on, then test the unit.
Turns are working erratically
If the fan will not turn from side to side or is stuck while turning, check the engagement of the gears in the gearbox.
It may be impossible to obtain spare parts for the gearbox. In this case, the only solution is to assemble the fan and use it in stationary mode.
IS NOT RUNNING SMOOTHLY
Fan defective
On a typical table fan the on/off switch is located in the base. Most fans have rubber or plastic feet or pads on the base to prevent slipping on smooth surfaces. The base cover screws are often hidden by these rubber bands.
- Remove the mounting screws and remove the base cover to access the on/off switch. One simple fan has a simple two-speed switch. No parts may be available for cheap fans, but a faulty switch can be tried to repair.
- Check switch for smooth operation, clean corroded or scraped contacts with a double folded fine grit emery cloth. Before installing the switch, sweep off the sanding dust.
DOES NOT WORK AT ALL
Faulty plug or fuse
Check the correct connection of the plug and replace the blown fuse. If the fuse blows again when you plug it in, take the unit to a repair shop.
No Power
If other devices in the same circuit have stopped working, look for a blown fuse or tripped circuit breaker or RCD on the switchboard
Broken cord
Test the cord with a tester. If the cord is secured with screws, replacing it with a new one will be easy enough.
Poor contact
Check the internal wiring contact and tighten all ground connections. Check that the ground is securely connected.
Faulty switch
Check and replace if necessary.
Defective motor
Even if a replacement motor can be purchased, it will probably cost almost as much as a new fan.
Repair of different types of the fan with your own hands
Broken fan should not be thrown out immediately, the most reasonable thing would be to understand the causes and, if possible, repair the device. Often, fan malfunctions are not associated with breakdowns, but simply require trivial cleaning and lubrication.
Some types of mechanical damage can be eliminated on their own, replacing the failed part. It is more difficult to repair floor or table models with a more complex design. Since fans are part of most modern devices for cooling and air conditioning, each case is different. We will consider only the most frequent causes of breakdowns and ways to fix them.
Repair the blower heater with their own hands scheme, causes of failure, thermal protection.
With the advent of the first cold weather, the main wand in the warming of our homes and offices, are not bulky oil radiators or convectors, and small and compact fan heaters.
They allow for a very short period of time, to raise the temperature in the room at once for several degrees.
However, as a result of exploitation, sooner or later there comes a moment when the fan stops working. What to do in this case? Run to the store for a Scarlet, Saturn or Comfort and hope that they are more reliable?
After all, they do not cost very much. However it is not necessary to buy another fan heater, if you can repair the existing one with your own hands.
In order to find the cause of the failure you need only two things. a screwdriver and a multimeter.
The most important thing is to determine whether there is a contact in this or that circuit or not. Let’s take a closer look at how fan heaters are designed, how to disassemble them, what often breaks down and trace the successive chain of checks of one element after another.
The first thing to do is to test and check the continuity of the power cord and all visible contacts. Maybe you don’t have to climb far into the guts of the device, and the trouble will be on the surface.
To do this, unscrew and remove the bottom or side cover, depending on your model.
Keep in mind that the center screws are not worth unscrewing from the beginning because they are used to hold the motor.
Take them away and all the innards fall apart. It is better to have the motor itself attached to one of the covers.
Next, you need to find the pins, where the 220v power wires come from. If you are lucky, sometimes without any tools you can immediately see a burned out wire.
Put it back in place and the repair is over. If the problem is more serious just feel and twitch all the clamps.
Since the fan during the operation vibrates, it is possible that some of them elementary went out of place. It is possible to detect bad contact on the terminal board by characteristic traces of burning.
Often such defects are the reason that the fan heater spontaneously turns on and off. Especially when you move it.
If you find something like this, clean up and then wipe the pad with a cotton swab soaked in alcohol.
Next, use pliers to gently squeeze the terminal and put it back on.
Only after all these manipulations, you can proceed to the testing with measuring instruments.
Switch the tester to the “test” mode, and use the styli to check the continuity of power wires one by one. To do this, touch the lead-in pins inside the ventilator and the metal pins on the plug.
If everything is OK, the tester will beep or show zero resistance.
If you have something going on when you plug it in, like a fan spinning, but the air is cold, then of course the cord has nothing to do with it. His test in this case can be omitted.
The same way you test a microswitch that is sometimes built into the case.
You switch its key and check to see if there’s a circuit.
These things often break down at high currents. The repair in this case is quite simple. Two wires that match it are bitten out and connected directly to each other.
The connection is insulated with a protective cap of PPE or simple duct tape.
The only disadvantage from now on is that the heater will work as soon as you plug it in.
When the switch is not involved, check the following circuit elements. By the way, do not forget about the mechanical part.
Immediately after opening the housing, try turning the blades by hand. They should spin freely.
Here you need to make sure that nothing is jammed and there are no foreign objects stuck on the shaft.
What other electrical elements in the circuit can fail? Immediately after the power supply leads are the thermostat and mode switch.
On the outside of the housing are the familiar handles, wheels.
Some people mistakenly take the thermostat for an element that controls the speed of the blades. In fact, it is a bimetal plate, and one of the wires from the plug comes to it.
When turning this knob you should hear a faintly audible clunking sound. It means that the thermostat turns on and off. If there is no separate micro-switch in the circuit, it performs its function.
You can also check the correctness of this element with a multimeter. Put the two probes on the contacts and twist the knob. The sound will come and go on and off in the test mode.
Using the same circuit, check the mode switch. By turning its knob, you turn on one tenor, two tenors, or just put the blower in fan mode without heating.
Only when you will remove the terminals for testing, it is better to take a picture of their original connection to your smartphone, so as not to mix up the contacts later.
Currents in these elements are not weak to about 10A. So it’s not uncommon for them to have circuit breakdowns. True, the first check of the thermostat and the 4-way switch can also be done by sniffing.
Contact burnout under such strain never goes away. Smoke and odor these things will definitely.
If everything is OK here too, let’s move on. Immediately next to the heating elements are two protection systems. They consist of a bimetallic plate and a 121-degree thermal fuse.
Both of these elements in good condition should give a circuit and make a sound when testing, i.e.е. to indicate a short-circuit through itself.
Remove it, and no ultrasonic or other devices can save you from arcing.
The power here goes to the right contact at the top. Then, through the fuse, the voltage goes to the left connector.
From this socket on top a cooler and sometimes a neon indicator is connected. And at the bottom, through the thermoplate, the power goes to the two resistors.
So if this main fuse blows, both the fan and the heater will stop working. When the bimetallic plate triggers, only the heating is turned off, the fan continues to rotate, cooling the coil.
On the back side of this double protection, on the opposite pins of the heating element, fit the wires from the mode switch.
By switching it on we connect either one fuse or two coils in the chain. It turns out that the fuse is fed by phase, and the contacts on the other side through the switch is zero. Or vice versa, depending on how you plugged in the socket.
Typical wiring diagrams for heater heaters are as follows:
Very often in this chain, it is the thermal fuse that is the main reason for the failure of the whole device.
over, its replacement is not as easy as it may seem at first sight. Not for nothing the factory here uses rivets, not soldering.
Soldering is not recommended here, because the soldering temperature rises above the calculated 121 degrees. But if you don’t have an outlet, you’ll have to use a good heat sink.
You take out the unusable fuse and flux the brass holes in the rivet areas.
Crimp the thermal fuse itself, and specifically the wires to it, tightly with tweezers or crooked long nose pliers. So during soldering the heat will be carried away through them without reaching the body.
Of course you will not get 100% removal of heat, but most of it will go through the wide jaws of the tool.
If you don’t want to solder at all you can use screws. The main thing is to have long bends.
Bend them with a ring and put small screws where the rivets are. With these screws you fix the fuse in its seat.
To choose and order a thermofuse for any temperature and amperage you can go from here.
If you did not find the exact degrees, choose models with temperature from 110 to 140C, no more.
Another fuse, or rather thermal fuse relay, which protects the motor itself, hidden pretty far away. It is designed to protect the windings from overheating.
The same protection is provided by common floor fans. You can read more about the specifics of checking and replacing them in the article at the link below.
Usually it is self-healing, that is, after some time after the windings cool down, the blower can be started again without any problems. It looks like this.
You plug in a cold fan heater, it runs for a while, then the blades stop rotating spontaneously. The heaters are still hot at first and then they shut down as well.
After cooling down, the whole cycle repeats again as if nothing had happened. If your device has similar symptoms, and the thermostat is not involved, look in the direction of this protection windings.
By the way, when the thermal fuse at 121 degrees burns out, look closely at the bimetal plate after it. There is probably something wrong with it as well.
It should be triggered earlier. Otherwise the fuse will blow again soon. So if you have any suspicions, it is better to replace both parts at once.
After repairing, be sure to bundle all wires together with wire ties and hide them away from the blades. Otherwise it could be cut with a screw.
And what to do and where to look, if the fan heater works, blows cold air, but does not warm? In this case the problem is in the bimetal plate going after the thermal fuse.
Either the soldered on nichrome coil of the heating element burns out or the contact on the plate itself loses. Reconnect with a tester and if necessary clean up and bend the contact pads.
You can also check the serviceability of such plates by touching them with a heated soldering iron. If enough heat is applied, the circuit will open and the tester will show a breakage. When it cools down, it shorts out.
If the heater itself is damaged, it is easier to buy another fan than to resolder the nichrome.
Also keep in mind that when in the wiring diagram blower motor is not strictly after the thermal fuse, its failure will also cause the fan blowing, but not heating. How to replace it was described above.
The heaters have a slightly different design, rectangular, also the main elements of protection are the fuse and bimetal plate. They are located under the spiral and are also seated on the rivets.
Their testing is easier than in the previous variants. First, set the position switch to zero (off).
On the reverse side, use a tester to check the resistance of the rivet contacts. If at least one element fails, you will not get any signal or sound from the multimeter. The resistance will be shown as infinity.
That’s why you have to wire the elements individually. In the photo below you can see that the bimetal disconnector has nothing to do with it, it has a circuit.
If the motor on any model is damaged (coil is hot, blades are not turning, and the thermostat is intact), the only thing you can do is check the shaft wedge for dust or other foreign objects.
If there are more serious damages, the engine repair is not really expedient. In this case it is much easier to buy a new fan heater.
