What are HVAC transformers? HVAC transformers allow different supply voltage currents to pass through, and power the components in an HVAC unit. The transformer transfers electrical energy from the power source to the HVAC system, adjusting the voltage according to what each component needs.

For instance, the transformer provides low-voltage energy to the thermostat, which requires only low voltage power. This prevents a power surge from happening, and enables the HVAC unit to operate smoothly.

Diagnosing a Faulty Transformer

#1 Power Surge

Transformers prevent power surges by transferring low and high-voltage power to the different components of the HVAC system. A power surge indicates a faulty transformer, which needs to be replaced immediately to avoid breaking the entire unit. Symptoms of a power surge include a tripped circuit breaker, high energy bills, and faulty components.

#2 High Electricity Bills

High electricity bills may also be attributed to a faulty transformer. The transformer is supposed to regulate the power supply that flows through the unit, and if it cannot regulate the supply, then it may trip a circuit breaker, cause a power surge, or spike your energy bills. You can check for a faulty transformer using a voltage test meter.

#3 HVAC System Won't Turn On

If the HVAC system won't turn on, it can mean a number of problems with the components. One of the causes for an HVAC system that won't work is a busted transformer. A licensed HVAC technician will be able to pinpoint the exact cause of the problem.

How to Replace an HVAC Transformer: A Step-by-step Guide

Step 1: Cut the Power from Your HVAC System

Replacing a furnace transformer or an HVAC transformer can be hazardous, so it is best to leave the repair work to the professionals. If you have the experience and skill to do the replacements yourself, make sure to cut the power from your HVAC unit, and wear protective gear before attempting to replace the furnace transformer.

Step 2: Unscrew the Old Transformer

Now, you will need to remove the faulty transformer, and the old wires connected to it. Unscrew the bolts fastening the old transformer in place. The transformer wires should have high-voltage, and low-voltage wires. You will need to cut these both with wire cutters to attach them to the new unit later on. It is helpful to take a reference photo of the connections.

Step 3: Attach the New Transformer

Refer to the photo you took of the old transformer and its supply wires, and place the new transformer into the unit the same way. Connect the supply wires and the secondary wires to your new unit, and secure them with wire nuts. Place an amp probe on one of the high-voltage wires connected to your new unit.

Step 4: Restore the Power

Restore the power to your HVAC unit, and use a voltage tester to test out the repairs. A successful repair should bring back a reading of 24 volts, and pull less than .999 amps. If this is not what is presented on the meter, then you will need to revisit the wiring.

Looking to replace the whole HVAC system? Read this guide.

How Much Does it Cost to Replace an HVAC Transformer?

The average cost to replace a furnace transformer is around $100 to $200, while air conditioner transformers can go as high as $650. The majority of the replacement costs go to labor, as repairing the HVAC transformer is hazardous, and requires training.

Where to Buy a Replacement Transformer

#1 Hardware Stores

If you are aware of the type of transformer and transformer wires you need for your HVAC system, then you can find these at select hardware stores that carry parts and components for HVAC units. Some hardware stores even carry specific brands that are used in your HVAC system, but you will have to install the replacement parts yourself.

#2 Luce Aircon

At Luce Aircon, we offer purchasing services for all our clients, and provide assistance to find the exact unit or part that you're looking for. We also offer repair services for any HVAC system, so you can get the full repair package when you avail of our services.

Check out our full list of services, and contact us to keep your HVAC system up and running smoothly!