One of my HVAC Units Quit Working
Repairing an HVAC Unit that Quit Working: Replacing HVAC Electrical Parts and System Components, Causes of a Melted Electrical Wire on a HVAC Unit.
Electrical Repairs for an HVAC Unit
- I checked inside the outside unit and found the relay and found it melted, and the white wire going to the relay also had the insulation melted.
- Then I checked the max amperage rating listed on the unit, it showed 25 amps.
- The breaker at the disconnect is 60 amps. Why would they do this?
- I just now ordered a replacement internal breaker and installed a 30 amp breaker at the disconnect. Is that Okay?
- Also, please let me know if I should match the disconnect breaker on the other unit with what is labeled on that unit.
This electrical wiring question came from Jim, in Somerville, Alabama.
Additional Comments: Incredibly awesome, wish I had found it many years ago. Thanks!
Thanks for your electrical wiring question Jim.
Repairing an HVAC Unit that Quit Working
Application: Replacing Electrical Parts for a HVAC Heating Ventilation and Air Conditioning.
Skill Level: Beginner to Intermediate – Best performed by a trained HVAC Service Technician.
Tools Required: Basic Electricians Pouch Hand Tools and Voltage Tester.
Estimated Time: Depends on personal level experience and ability to work with tools.
Precaution: Identify the HVAC circuit at the electrical panel, turn it OFF and Tag it with a Note before working with the wiring and electrical components. Record the wiring connections before removing any wiring connections.
Repairs for a HVAC Unit
- Replacing HVAC Electrical Parts and System Components
The replacement components, relay and circuit breaker should have the same specifications as the original equipment as originally specified by the furnace manufacturer.
- Causes of a Melted Electrical Wire on a HVAC Unit
A loose or incorrect wire connection can cause a wire arc and over heat to the point of melting the insulation on the wire. An incorrect wire gauge size and type of insulation can also case a wire to overheat which can damage the insulation.
- HVAC Condenser Motor and Refrigerant Compressor
All the HVAC system components should be tested for normal operation within the specifications found on the HVAC unit specifications and individual electric component labels. Faulty system components can cause abnormal operation which can cause overheated conditions and circuit overloading of the electrical circuit
- HVAC Unit Specifications
Not all HVAC units are alike, so it is essential that the electrical specifications are identified from either the equipment label or the manufacturers installation or owners manual. If it is found that the HVAC system components have been altered outside of the original specifications then restoring the system to it’s original state is recommended.
More about Relays
HVAC Control Relays
The use of relays that are sometimes needed to control special device loads such as Air Conditioners and other high demand equipment from starting at the same time.
Home Electrical Circuit Breakers
A guide to home electrical circuit breakers and how they work to protect your electrical wiring. When properly installed, your home electrical wiring is protected by a circuit protection device.
Electrical Wire for the Home
Complete listing of electrical wire types and parts used for home projects with electrical code information serves as selection guidelines.