Replacing a Blower Motor for an HVAC System
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How can I Adjust The Speed on an HVAC Blower Motor? Speed variations and wiring configurations of a Blower Motor. |
Wiring Options when Replacing a Blower Motor
Electrical Question: How can I adjust the speed on an HVAC blower motor?
- I just replaced the HVAC blower motor at a rental unit.
- The new motor gives a choice of permanent wiring for high, medium, or low speed.
- Both the high and medium give adequate CFM for the HVAC system.
- I’d like to give the tenant the ability to switch from high to medium to reduce the noise, but I can’t seem to find a 230Volt changeover switch without an “off” setting.
- Where can I find a universal cam changeover switch, or similar product for home HVAC use?
This HVAC Question came from: Kevin, a Handyman from Sacramento, California.
Additional Comments: Awesome! But need to add an article on changeover switches.
Dave’s Reply:
Thanks for your HVAC Question Kevin.
How to Control the Blower Motor Speed on a HVAC Blower Motor
Application: Replacing a Blower Motor – HVAC Heating Ventilation and Air Conditioning
Skill Level: Intermediate to Advanced – Best wired by a Licensed Electrical Contractor, or by a Licensed HVAC Furnace Contractor.
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 furnace circuit at the electrical panel, turn it OFF and Tag it with a Note before working with the blower motor wiring. record the wiring connections before removing any spliced wiring connections.
Wiring Connections and Settings: The replacement blower motor should have the same specifications as the original motor. The wiring connections should be made for the suggested blower speed as recommended by the furnace manufacturer
Furnace Blowers for HVAC, Heating Ventilation and Air Conditioning with a Universal Cam Changeover Switch to Reduce Motor Speed
- With this question for Kevin, this would be a rare setup which is not commonly available to be adjusted outside of the unit because
- The variation or amount or air flow may have an effect on vital parts and processes of the HVAC unit including but not limited to:
- The air flow and pressure effect on the HVAC duct system components.
- The design capabilities for the size of the HVAC unit.
- The ability to cool or heat the interior of the home.
- The speed settings should be set according to the manufacturers specifications for the specific HVAC unit and the specific factors of the home.
- The variation or amount or air flow may have an effect on vital parts and processes of the HVAC unit including but not limited to:
- Speed Control Methods for a multi- speed 220 volt motor.
- Double pole Double throw switch.
- Low voltage control relay unit.
- Electrical wiring required would be specific to the method selected.
IMPORTANT NOTE:
When Replacing a Blower Motor only install HVAC controls options or methods that are only approved for the specific unit that you have.
HVAC Blower Motor Speed Adjustment
- How to Adjust the Blower Motor Speed
- The HVAC unit is configured for a certain amount of air flow that will be correct for each unit in order to maintain the proper level of heating and cooling.
- Changing the speed of the blower motor should only be done with the assistance of an HVAC technician.
- Blower motors that have the capability for adjusting the speed are indicated in the Owners and Installation Manual which comes with the unit, and on the schematic of the unit.
- Speed variations and wiring configurations are specified on the blower motor, which will indicate the wiring connections specific for the motor.
- IMPORTANT: Increasing or decreasing the speed of the blower motor will affect the performance of the HVAC System and may have an adverse effect on the HVAC ducting system components.
- NOTE: Not all blower motors have the option for changing the blower speed
More about Home Electrical Wiring
Wiring a Light Switch – Diagram 1
- Wiring Diagrams
- Fully Explained Light Switch Wiring Diagrams. Detailed Electrical Wiring Diagrams and Pictures assist your Home Electrical Projects.
- Understanding Electrical 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.
You identified your project to be about 220 Volt Wiring Diagram, so you might find this information useful:
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Wiring 220 Volt Electrical Outlet
- Home electrical wiring includes 110 volt outlets and 220 volt outlets and receptacles which are common place in every home. See how electrical outlets for the home are wired.
The following may also be helpful for you:
Learn more about Home Electrical Wiring
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Be Careful and Be Safe - Never Work on Energized Circuits!
Consult your Local Building Department about Permits and Inspections for all Electric Wiring Projects.
The Safest Way to Test Electrical Devices and Identify Electric Wires!The Non-Contact Electrical TesterThis is a testing tool that I have had in my personal electrical tool pouch for years, and is the first test tool I grab to help identify electrical wiring. It is a Non-contact tester that I use to easily Detect Voltage in Cables, Cords, Circuit Breakers, Lighting Fixtures, Switches, Outlets and Wires. Simply insert the end of the tester into an outlet, lamp socket, or hold the end of the tester against the wire you wish to test. Very handy and easy to use.
The Quickest Way to Check for Faulty Electrical Wiring!The Plug-In Outlet TesterThis is the first tool I grab to troubleshoot a problem with outlet circuit wiring. This popular tester is also used by most inspectors to test for power and check the polarity of circuit wiring. It detects probable improper wiring conditions in standard 110-125 VAC outlets Provides 6 probable wiring conditions that are quick and easy to read for ultimate efficiency Lights indicate if wiring is correct and indicator light chart is included Tests standard 3-wire outlets UL Listed Light indicates if wiring is incorrect Very handy and easy to use.
Strip Off Wire Insulation without Nicking and Damaging the Electric Wire!The Wire Stripper and Wire CutterMy absolute favorite wire stripping tool that I have had in my personal electrical tool pouch for years, and this is the tool I use to safely strip electrical wires. This handy tool has multiple uses: The wire gauges are shown on the side of the tool so you know which slot to use for stripping insulation. The end of the tool can be used to grip and bend wire which is handy for attaching wire onto the screw terminals of switches and outlets.. The wire stripper will work on both solid and stranded wire. This tool is Very Handy and Easy to Use. |
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I bought a new electric blower motor for a wood burning furnace. I wired it to an existing outlet. The black wire to black wire, and the white wire to the white wire. When I plugged it in sparks come from the motor and I can smell wire burning. I unplugged it right away, but is the motor bad or my wiring.
Hi John,
When something like this happens where the motor fails there are two things I would check. First, check the voltage of the motor to make sure it is the same voltage as the outlet that will be supplying the power. Next, I would make sure the power of the outlet is correct and compatible with the motor voltage. If there were sparks when you plugged the motor in then I would also double check to make sure that the wiring is not damaged and the connections inside the motor are correct.
Dave