Concord Furnace Pressure Switch Problems and Solutions
When your Concord 80 Plus Furnace blower keeps running but fails to ignite, it can be incredibly frustrating—especially during freezing temperatures. Many homeowners face this issue, particularly when external components like pressure switches or inducer fans fail. Fortunately, with a step-by-step understanding of common causes and their fixes, you can identify and resolve the problem effectively.
This blog will cover the most likely causes of this problem, from pressure switches and inducer fans to dirty or blocked components. We’ll explore the root causes, detailed solutions, and answer frequently asked questions to help you restore heat quickly. If you’re struggling with your furnace and need guidance, this comprehensive breakdown will walk you through the issue.
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Understanding the Concord 80 Plus Furnace Blower Behavior
The Concord 80 Plus is a reliable and efficient furnace system, but like any system, it can encounter problems. If your blower runs for a short period but the furnace does not ignite, several components could be at fault. Let’s look into the blower behavior first and determine the most common causes.
What is the Blower Doing?
The blower motor typically runs to circulate air through the system when the furnace starts up. When it fails to ignite after a short period, it could be indicative of an electrical issue, pressure switch failure, or other malfunctions. The blower running without ignition can lead to unnecessary energy consumption and cold indoor temperatures.
Some common causes include:
- A dirty or blocked pressure switch.
- Faulty inducer fan or related mechanisms.
- Failed ignitors or miscommunications between the thermostat and system.
Understanding the behavior will give you a clear troubleshooting path.
Why the Blower Turns On for a Short Time
When you notice the blower engaging only briefly, the system is likely attempting to start the ignition sequence but failing at a key step. The most common reasons for this are:
- Faulty Pressure Switch: Pressure switches control airflow to ensure proper ignition.
- Dirty Inducer Fan Components: A blocked fan will disrupt air pressure and prevent ignition.
- Thermostat Malfunction: A malfunctioning thermostat might send incorrect signals to the furnace system.
- Ignitor Failure: A non-functional ignitor means no gas ignition can occur.
Identifying the root cause requires inspecting these components carefully.
Common Causes of the Concord 80 Plus Blower Problem
When diagnosing a furnace with a blower that runs but fails to ignite, the following reasons are likely culprits. We’ll break each cause down for easier understanding.
1. Faulty Pressure Switch
The pressure switch ensures the furnace has adequate airflow before the ignition sequence begins. If this component is malfunctioning or stuck, the furnace won’t ignite. A faulty pressure switch is often one of the most common reasons for blower issues.
How to Spot a Faulty Pressure Switch?
- The pressure switch indicator lights flash a code (e.g., three times).
- The system fails to advance through its startup sequence.
You can test a pressure switch by disconnecting the two wires, taping them together, and attempting to restart the furnace. If the furnace runs, you likely need to replace the pressure switch.
2. Blocked Inducer Fan Components
The inducer fan pulls air through the combustion chamber to create the necessary conditions for ignition. If the inducer fan is blocked, dirty, or failing, the system won’t generate the airflow required for ignition.
Signs of a Blocked Inducer Fan:
- Blower runs but fails to ignite.
- The pressure switch does not click when checked.
To resolve this, inspect the hose connected to the inducer fan for blockages or debris. Using a small, thin object to clear out debris may solve the issue.
3. Dirty or Obstructed Pressure Switch Hose
The pressure switch relies on the correct pressure levels, transmitted through a flexible hose. When this hose becomes dirty, blocked, or damaged, the system fails to achieve proper pressure, and the furnace won’t ignite.
Quick Test for a Blocked Hose:
- Disconnect the hose from the inducer fan.
- Lightly suck on it to check for a click. If you hear a click, the switch is working but the hose may be blocked.
Cleaning this hose or replacing it can restore proper airflow and resolve the issue.
4. Ignitor Problems
The ignitor must glow to ignite the gas entering the combustion chamber. If it fails to glow or is damaged, the gas won’t ignite, and the blower will cycle briefly without success.
Signs of Ignitor Problems:
- The ignitor doesn’t glow when the system attempts to start.
- There is a clicking sound without gas ignition.
Check the ignitor’s condition and clean off dust or corrosion. If it continues to malfunction, replacement is necessary.
5. Thermostat Malfunction
The programmable thermostat controls communication with the furnace system. If the thermostat fails, sends incorrect signals, or has dead batteries, the system won’t operate properly.
How to Test Your Thermostat?
- Replace the thermostat batteries with fresh ones.
- Set the system to “heat” and monitor its response.
A thermostat issue might be simple to fix, but ensure you rule it out by addressing low-battery warnings and resetting the system.
6. Dirty Flame Sensor
The flame sensor monitors whether a flame is present during the ignition sequence. If it is dirty or faulty, it prevents the system from progressing. This causes the blower motor to cycle without ignition.
Cleaning the Flame Sensor:
- Locate the flame sensor near the burners.
- Clean it using a fine-grit sandpaper or steel wool.
A clean flame sensor ensures proper detection and allows ignition to proceed.
How to Fix the Pressure Switch Issue
If you’ve already identified that the problem stems from the pressure switch or related components, here’s how you can fix it.
Step 1: Inspect the Pressure Switch and Hose
Check the pressure switch for visible signs of damage or debris. Ensure that the hose leading from the draft inducer fan to the switch is clear of obstructions. A small piece of debris can block airflow and prevent the system from functioning.
Step 2: Replace the Pressure Switch
If you’ve confirmed that the pressure switch is faulty, replacing it is a straightforward solution. Disconnect the old switch and connect the new one. This is usually a quick, inexpensive repair.
Step 3: Clear the Inducer Fan Vent
Sometimes blockages from debris can cause your system to act erratically. Inspect the exhaust fan vent using a paperclip or thin object to clear dust or debris safely.
FAQs About Concord 80 Plus Furnace Problems
Why does my blower turn on but no heat is produced?
This issue is likely related to a faulty pressure switch, inducer fan, or ignitor issue.
How can I check if the pressure switch is faulty?
You can disconnect the two wires from the pressure switch and tape them together. If the system runs, the switch likely needs replacement.
Should the ignitor glow when the system attempts to ignite?
Yes, the ignitor should glow bright red when functioning properly during the ignition sequence.
How can I clean a clogged hose connected to the pressure switch?
Disconnect the hose, remove debris with a paperclip, and ensure airflow is unobstructed.
Conclusion
The Concord 80 Plus furnace blower running without ignition typically stems from pressure switch malfunctions, dirty inducer fans, or thermostat issues. Testing individual components such as pressure switches and flame sensors can help narrow the issue. With careful troubleshooting, most problems can be identified and resolved quickly, restoring your heat.
If problems persist, consider contacting a professional HVAC technician. Taking prompt action during cold weather ensures that your home stays warm and safe.
