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What Causes a Transformer To Blow In a Furnace?

transformer on furnace keeps blowing

What Causes A Transformer To Blow In A Furnace? 

The main reasons for a transformer to blow in a furnace are loose wiring, the accumulation of dust, and worn out components.

  • Accumulation of Dirt and Debris: If you have not paid any heed to the maintenance of your furnace, the various parts are likely to collect dust. Once the dust reaches the blower motor, the motor starts overheating and burning out. As a result, the high limit fails and causes the transformer to blow up.
  • Loosening of Wires: Vibrations caused due to the functioning of the transformer can cause the internal wires to loosen up. This, in turn, leads to the risk of a short circuit. In order to avoid such accidents, it is important to ensure that the wires are tight and in good condition from time to time.
  • Worn out parts: If you hear strange noises coming out of your furnace, it may be an indication that some parts are worn out. The transformer of a furnace helps to convert the electrical signals to the right voltage. In case the transformer fails to do so, it may blow up.

Any malfunctioning of the furnace should be inspected by a professional technician. 

How to fix a furnace fuse that keeps blowing:
http://voltfixer.com /furnace-3-5-amp-fuse-keeps-blowing/


How To Check If the Furnace Transformer Is Bad

If you are facing issues with your electrical system, there might be a problem with your furnace transformer. One can check the functioning of a transformer using a digital multimeter. Here’s how:

  • Step 1: First, you will have to turn off the power supply to the circuit. You will also have to remove the panels and covers. Next, take a digital multimeter and take the accurate readings of voltage. The leads of the digital multimeter need to be attached to input lines. This helps to make sure that the transformer is not shorted.
  • Step2: Next, the transformer has to be checked by allowing current to flow through the circuit. In order to check is lower than the expected voltage by 80%, this can be indicative of a problem in the circuit that is providing the primary power or the transformer itself.
  • Step 3: Next, you will have to measure the transformer secondary. If there is filtering, you will have to harness the use of the DC scale of the digital multimeter. If not, you can stick to the AC mode. In case the expected voltage is not found on the secondary, it may be indicative of the fact that the transformer is faulty.


Bad Furnace Transformer Symptoms 

Any issues with the transformer may be difficult to identify. However, if you are wise enough, you may be able to catch the signals that might be indicative of a faulty transformer.

Some of the main symptoms are: 

  • A Drastic Increase In Vibration And Humming Sound: Transformers produce a humming sound. This happens because of the expansion and contraction of the iron core or the laminations. However, if you witness a rapid increase in the noise and the vibrations, it may be indicative of a faulty transformer. The vibration doesn’t always need to be caused due to an erroneous transformer. It may also be due to an error in the installation of the capacitor. It is always advised to call a professional technician and ask him to resolve the issue.
  • Transformer tripping frequently: If the transformer in your furnace is faulty, then the circuit breaker will trip often. This trip prevents voltage surge, thereby preventing a major breakdown.
  • Non-Functional HVAC: If your furnace uses a bad transformer, then your HVAC unit will not function properly, even if there is an adequate power supply.

All these symptoms are suggestive of the fact that your furnace transformer needs to be attended to.


How to test a oil furnace transformer? 

An oil burner is a device that is attached to a furnace transformer. The oil burner provides the ignition generated by biodiesel fuel or any other heating oil.

Below are the steps that you need to follow if you wish to test an oil furnace transformer: 

  1. First, you will have to disconnect the source of power. Unplug or turn off the breaker.
  2. Dismantle the inspection panels, locate the transformer, and bring it to a position where it is easily movable. Make sure you position the interiors such that the high voltage terminals can be touched easily.
  3. To avoid oil coming out as you inspect the transformer, disconnect the power source to the motor.
  4. Connect the oil burner to the source of power and turn it on.
  5. Take a well-insulated screwdriver and place it to the transformer’s output terminals in such a way that the screwdriver touches one terminal but not the other. The gap should form an arc. If the arc is shorter than three-quarters of an inch, or if there is no arc at all, then the transformer is faulty.


How to Fix Furnace Transformer Humming Noise 

All appliances make a certain amount of humming noise during functioning. When the noise exceeds the normal level, it becomes concerning.

There are a number of factors that might cause a humming noise and vibration in a furnace transformer. Sometimes, the blower motor may not have sufficient lubrication, causing a humming noise, and cause the motor to malfunction.

Apart from this, loose wiring, equipment, loosened ductwork, and failed capacitor can also cause a furnace to cause a lot of humming noise.

To get rid of his buzzing noise, it is important to hire a professional technician. To fix the issue, one has to follow the given steps:

  1. Tightening the parts may help: if all the parts of the device are fastened properly, it can reduce a considerable amount of noise.
  2. Avoid surfaces that amplify the noise: the furnace transformer should be mounted on a dense surface such as concrete. Mounting it on surfaces like thin plywood sheets amplify the noise and vibration.
  3. Cushion padding helps dampen the noise: Using a cushion padding that can absorb the noise and act as insulation, helps to cut down the vibration and reduce the noise.


Why your Furnace transformer is hot 

Sometimes, the transformer of a furnace is not designed to supply the amount of current that it is expected to. In such a case, the transformer tends to get overheated.

The flow of current leads to the generation of heat. The more the current amount begins to flow through the coils, the more the wires tend to get heated up. The repeated heating and cooling of the wires can cause them to turn brittle and lead to a failure in the long run.

Before you consider a complete overhaul, there are a few things that you need to consider:

  1. First, you have to make sure that the current flowing through the transformer is not overburdening it. It should be within acceptable limits.
  2. Next, you need to have a look at the oil levels. Insufficient levels of oil may cause your transformer to get heated up quickly.
  3. Thirdly, check if your furnace transformer has any faulty connections. If you find any connection issue, try to resolve it.


If following the above mentioned steps doesn’t help, your furnace  transformer probably needs to be replaced.


Why does HVAC transformer keep blowing?

The term HVAC refers to heating, ventilation, air-conditioning. HVAC units have a primary device known as the thermostat. These thermostats help in temperature regulation.

Like all brands, I have experienced HVAC transformers that can keep blowing. This can happen due to a number of reasons such as a surge in power, loose cables or wiring, or a bad contractor that overburdens the entire unit. When the unit fails to handle the strain, the HVAC transformer tends to blow off.

However, this kind of malfunctioning can be taken care of. Call a technician and ask him to replace the faulty component. You can also get rid of any part that has melted, and the device will start functioning as new!

Electrical components need timely maintenance. Even the slightest ignorance can lead to massive havoc in the future. Therefore, try to schedule a maintenance session after a specific interval and prevent such nuisances in the future!

Ernie Lo

Ernie Lo is a qualified web designer and web developer. He works as an IT support technician and website manager at Benleigh Vending, and he also fixes vending machines.

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