Electric furnaces are among the most efficient and reliable solutions for whole-home heating, especially in homes without access to natural gas. One of the most critical components of an electric furnace, including the Goodman MBVK, is the heat strip. Proper operation of these strips depends on correct installation, staging, and wiring. For homeowners and technicians alike, understanding the electric heat strip wiring diagram or heat strip wiring diagram is essential for troubleshooting, maintenance, and safe operation.
In this guide, we’ll explore the principles behind electric heat strips, provide insights into Goodman MBVK wiring, discuss common problems, and share practical tips to keep your furnace running smoothly.
What Is a Heat Strip?
A heat strip is a type of electric resistance heater. When electricity flows through the strip, the electrical resistance converts the energy into heat. This heat is then transferred to the air, which the blower motor distributes throughout your home.
Heat strips come in various sizes and configurations, depending on the furnace’s design and heating capacity. In the Goodman MBVK, the heat strips are staged to optimize energy use and prevent sudden high electrical loads.
Unlike gas furnaces, electric heat strips do not produce carbon monoxide or rely on combustion. Their efficiency and safety make them a preferred choice for many homeowners, especially in regions where electric utility rates are competitive.
For a general overview of electric heating systems and safety tips, the U.S. Department of Energy provides an excellent resource.
The Importance of Wiring Diagrams
The electric heat strip wiring diagram shows how each heat strip is connected to power, control devices, and safety switches. Without it, troubleshooting and installation can become confusing or dangerous.
Key reasons wiring diagrams matter:
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Safety – Ensures the system is wired correctly and prevents electrical hazards.
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Troubleshooting – Helps diagnose why a heat strip isn’t heating.
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Maintenance – Guides technicians on proper reconnection after replacement.
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Staging Understanding – Shows which heat strip energizes first and how sequencing occurs.
The heat strip wiring diagram is the backbone of diagnosing common issues such as uneven heating, blown fuses, or short-cycling of the furnace.
For technical guidance on HVAC wiring and schematics, ACCA offers professional resources and best practices.
How Heat Strips Work in the Goodman MBVK
The Goodman MBVK electric furnace is designed to maximize comfort while reducing energy spikes. Heat strips in this model are staged across multiple elements:
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Primary Stage – Energizes the first set of heating elements when the thermostat calls for heat.
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Secondary Stage – Additional elements are energized if more heat is required.
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Sequencing – Heat sequencers control the timing between each stage to avoid overloading circuits.
The furnace blower motor usually starts after the first stage of heating to ensure warm air is delivered instead of cold drafts. This sequence is critical for both comfort and electrical safety.
A well-illustrated heat strip wiring diagram shows the connections between:
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Line voltage (usually 240V for MBVK units)
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Sequencers or relays
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Safety devices like limit switches
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Blower motor control circuits
Common Components Shown on a Heat Strip Wiring Diagram
When examining a heat strip wiring diagram for a Goodman MBVK furnace, you’ll typically see:
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Heating Elements (Heat Strips) – Shown as zig-zag lines or rectangles, each connected to sequencer outputs.
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Heat Sequencer – Controls staged operation and blower delays.
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Limit Switches – Protect the furnace from overheating.
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Thermostat Wiring – Low-voltage signals that control sequencing.
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Blower Motor Relay – Activates the blower motor after the heat strip reaches operating temperature.
Each component must be properly connected to ensure safe operation. Miswiring can cause blown fuses, insufficient heating, or even fire hazards.
For safe wiring practices and component identification, NFPA provides standards for residential electrical systems.
How to Read a Heat Strip Wiring Diagram
Understanding a heat strip wiring diagram requires distinguishing between low-voltage control circuits and high-voltage power circuits.
Step 1: Identify Power Supply Lines
The main electrical feed (typically 240V) connects directly to the heat strip elements via the sequencer.
Step 2: Follow Sequencer Connections
Sequencers introduce a delay between element activation to prevent high-current surges. Each output terminal is connected to a specific heat strip stage.
Step 3: Locate Safety Interlocks
High-limit switches or thermal cutoffs are wired in series with the heat strips. If a limit switch opens, the circuit interrupts and prevents overheating.
Step 4: Map the Blower Motor
The blower motor wiring shows how it receives power once the heat strip reaches operating temperature. This ensures warm air is delivered efficiently.
Common Problems Related to Heat Strip Wiring
1. Heat Strip Not Heating
If a heat strip does not energize, the wiring diagram can help trace the issue:
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Check sequencer output
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Inspect limit switches
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Test heating element continuity
2. Blower Running Without Heat
If the blower operates but no heat is delivered, it often indicates a wiring problem between the sequencer and heating elements.
3. Uneven Heating
Incorrect sequencing or failed wiring connections can cause some heat strips to energize while others remain off.
4. Tripped Circuit Breakers
Shorted heat strips or miswired elements may cause repeated breaker trips. The wiring diagram helps identify the correct paths and prevent electrical overload.
For professional guidance on diagnosing electric furnace issues, Energy.gov offers detailed safety tips and maintenance instructions.
Replacing or Servicing Heat Strips
When servicing a Goodman MBVK heat strip:
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Turn off power at the breaker
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Label wires before disconnection
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Compare wiring to the electric heat strip wiring diagram
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Replace the strip with manufacturer-approved parts
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Reconnect according to the diagram
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Test furnace operation
Following the diagram ensures safe and correct operation. Do not attempt to bypass sequencers or safety switches, as this can create a hazardous condition.
For tips on electric heating maintenance and replacement parts, HVAC Excellence provides detailed resources.
The Role of Heat Sequencers in Wiring
The sequencer is a small but critical component shown on every heat strip wiring diagram. It:
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Delays the blower motor start until the heat strip is warm
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Stages multiple heat elements
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Protects circuits from high inrush current
In the MBVK, sequencers also help reduce wear on relays and contactors, contributing to the furnace’s long service life.
Safety Precautions When Working With Heat Strip Wiring
Electric heat strips operate at high voltage and can be deadly if mishandled. Always:
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Disconnect all power before inspecting wiring
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Use insulated tools and a multimeter rated for the system voltage
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Follow the manufacturer’s wiring diagram exactly
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Never bypass limit switches or sequencers
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Replace components with approved parts only
Proper wiring and adherence to diagrams protect both you and your home.
Troubleshooting Checklist Using a Heat Strip Wiring Diagram
For technicians and informed homeowners, a wiring diagram allows systematic troubleshooting:
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Verify line voltage at the furnace
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Check continuity of heating elements
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Inspect sequencer operation and connections
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Test limit switches and high-limit cutoffs
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Confirm thermostat signal is reaching the control circuit
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Ensure blower relay wiring matches diagram specifications
Following this checklist in conjunction with the electric heat strip wiring diagram helps identify issues efficiently and safely.
Final Thoughts from Samantha Reyes
The electric heat strip wiring diagram is more than just a technical drawing—it is a blueprint for safe, reliable home heating. Understanding the diagram, the sequence of operations, and the interaction between components allows homeowners and technicians to maintain comfort and prevent costly or dangerous failures.
Whether you’re troubleshooting a non-heating furnace, installing replacement strips, or simply trying to understand your Goodman MBVK, the wiring diagram is your most important reference. By following it carefully, you ensure that your electric furnace delivers consistent warmth, maximum efficiency, and long-lasting performance.
Electric heat strips may be simple in concept, but their proper installation and wiring are critical. Take the time to study the heat strip wiring diagram, follow manufacturer guidelines, and maintain your system regularly. The result is reliable, safe, and efficient heating season after season.
