Table of Contents:
- Furnace or Boiler Not Firing? What They Are and How We Can Help
- How They Work Together in a Heating System
- Common Signs Your Igniter or Flame Sensor Is Failing
- Why It’s Often a DIY Risk and When to Call an Expert
- How Evergreen Heating & Cooling Diagnoses and Fixes These Issues
- Cost Factors: Igniter vs. Flame Sensor Repairs
- Preventative Maintenance Tips to Avoid Future Failures
- Final Thoughts: Stay Warm, Stay Safe
Furnace or Boiler Not Firing? What They Are and How We Can Help
When your furnace or boiler won't fire up properly, it's not just an annoyance, it's an indication that an important component is not functioning properly. At Evergreen Heating & Cooling, we often see an issue where the system will try to begin, but a defective igniter or flame sensor won't allow it to hold. The good news is, these are issues that can be repaired! We are ready to help you understand what is happening, how to tell, and when to call for some help.
Is Your Furnace or Boiler Not Firing? Evergreen Heating and Cooling Can Help!
Contact Ben at Evergreen Heating & Cooling
How They Work Together in a Heating System
Your heating system (furnace or boiler) has a very specific sequence of events that has been timed to ignite the fuel, produce heat, and operate safely. Here is a basic outline:
- When the thermostat calls for heat, a control board tells the system to start.
- An igniter (or pilot in an older system) creates a spark to ignite the fuel (gas in most systems).
- A flame sensor (or flame detector) confirms that a flame has been established. If the sensor does not detect a flame, it will shut the system down, preventing fuel from accumulating.
- Once the flame has been confirmed, heat is produced and distributed through air (furnace), or water/steam (boiler).
- The process will repeat until the thermostat is satisfied and then safely shuts the system down.
When the igniter or flame sensor fails in some way, the system may attempt to start, then fails (or refuses to start). At Evergreen, we help homeowners in the New Haven area walk through these components and get them back to working reliably.
Common Signs Your Igniter or Flame Sensor Is Failing
These are the warning signs to look for. If you notice them early, you might avoid a complete breakdown of your system or costly emergency service.
Furnace or boiler turns on but shuts off quickly
You hear the system start up. Perhaps the blower or pump is running, but the heat doesn’t last and it shuts down quickly. When this occurs, the most likely reason is that the flame sensor did not detect reliable flame, and for safety reasons the system has locked out.
No ignition spark or delayed ignition
Your furnace does not make any sound (no ignition attempted), or you hear a delayed “whoosh” when it finally ignites. When this occurs, either the igniter is too weak or failing, or the flame sensor has caused the system to lock out over and over again, which makes for a longer period before ignition.
Visible buildup or damage on the sensor
Flame sensors are located inside the combustion chamber, and like anything, over time they will get dirty or have mineral/soot buildup on them, affecting their ability to truly “see” the flame. If you can safely inspect the flame sensor, and you are comfortable doing so, brownish coating or visible damage is a clear red flag.
Why It’s Often a DIY Risk and When to Call an Expert
You might be tempted to just clean the sensor yourself or change a part, but that comes with safety and performance risks:
- Working inside a combustion chamber or boiler involves the presence of gas, high temperatures, ignition sources and safety interlocks.
- It’s quite pricey if you misdiagnose the issue, and it may result in continuing issues (or worse unsafe operation).
- Modern systems require proper calibration and sometimes reprogramming fault codes or monitoring lockouts.
- Also, if you don’t do the DIY repair correctly, you could void any factory warranties from the manufacturer.
Call in an expert if you regularly see ignition failures (frequently after service technicians have cleaned things out) or if you don't want to take on the risks. At Evergreen, our certified technicians take care of these safely and effectively.
How Evergreen Heating & Cooling Diagnoses and Fixes These Issues
Inspection steps
- We arrive at your residence and initiate a comprehensive system assessment: thermostat settings, fault codes, control panel recordings.
- Next, we take a visual examination of the ignitor and flame sensing fin as to its getting older, wear and whether any damage or buildup has begun to occur.
- We measure the proper test leads ignitor resistance, flame sensing volts, and ignition sequence.
- We also evaluate the venting and combustion system to eliminate the possibility of underlying issues (i.e., blocked flue, combustion air supply restriction) causing the continued failure.
Typical replacement or cleaning procedures
- If the flame sensor is just dirty or fouled, we clean it with proper materials (never sandpaper as it will ruin the sensor) and test the operation of the system.
- If the igniter shows signs of failure (i.e. weak glow, element cracked) we recommend full replacement with a new manufacturer recommended part.
- Whenever we replace or clean a component we verify operation, test the system through multiple cycles and verify reliable ignition and flame sensing before we leave.
- We also give tips on what you can check going forward to better prepare you and to avoid the unnecessary repeat visit.
Cost Factors: Igniter vs. Flame Sensor Repairs
Several factors can affect the price when working with igniters or flame sensors:
- Parts costs: Igniters usually cost more than a simple flame sensor, this somewhat depends on the system and the manufacturer.
- Labor time: Accessing igniters usually entails more disassembly (especially boilers), increasing the labor expense.
- Types of system: High efficiency furnaces or boilers (condensing types) could have a more complex ignition system and labor expenses could be higher for diagnosing and repairing.
- Underlying issues: If the underlying issue is a dirty burner, blocked vent, or improper air, the cost will increase for the technician to correct the additional issues.
- Warranty/age: Older units may warrant some parts or upgrades to current codes which may add to the cost.
We give you a complete and transparent price before commencing work, and will review options (cleaning, replacement, or total system assessment).
Preventative Maintenance Tips to Avoid Future Failures
- Once a year, schedule your professional tune-up (preferably) in the fall, prior to major use. The technician will inspect and clean the igniter and flame sensor during this service.
- Keep the area surrounding your furnace or boiler clean and free of debris; don’t restrict intake air from being blocked.
- Change your air filter regularly (for furnaces) as a clogged filter increases strain on the system and can reduce blower life.
- Look for blockages, in exhaust vents and flue pipes, corrosion, or back-drafting.
- If you notice any odd behavior (hesitating to start, odd smells, short cycling frequently), do not hesitate to call for service.
Final Thoughts: Stay Warm, Stay Safe
If your furnace or boiler doesn't fire, it may just be a faulty igniter or flame sensor; nonetheless, this situation can lead to more than just discomfort in your home. This also complicates safety, reliability, and efficiency. At Evergreen Heating & Cooling, we love to help homeowners in the Greater New Haven/Shoreline Area diagnose and fix these types of issues to ensure that your heating system is performing at its best all winter long. If you are having ignition issues, or haven't had a fall check-up yet, please call and let us help you get ready for the cold. Stay warm, and safe!
