Lennox SLP98 furnace

5March 2023

Lennox SLP98 furnace

The Lennox SLP98 furnace is a high-efficiency gas furnace that boasts an impressive Annual Fuel Utilization Efficiency (AFUE) rating of up to 98.7%. With such a high rating, it is no wonder that many homeowners choose the SLP98 as their go-to furnace for reliable and efficient heating.

However, like any furnace, it can experience some issues from time to time.

In this post, we will discuss some common troubleshooting tips for the Lennox SLP98 furnace, as well as provide answers to some frequently asked questions.

Common Troubleshooting Tips for the Lennox SLP98 Furnace


  1. Check the air filter: A dirty or clogged air filter can cause a wide range of issues, including reduced airflow, decreased efficiency, and even system shutdowns. Check the air filter regularly and replace it if necessary.
  2. Check the thermostat: If the furnace isn’t working properly, the thermostat may be the culprit. Check the thermostat settings and make sure it is set to “heat” mode. If it’s battery-powered, replace the batteries.
  3. Check the gas supply: Make sure that the gas supply to the furnace is turned on and that the gas valve is open. If the gas supply is off or the valve is closed, the furnace won’t function.
  4. Check the igniter: If the furnace isn’t turning on, the igniter may be faulty. Inspect the igniter for cracks or damage and replace it if necessary.
  5. Check the flame sensor: If the furnace turns on but quickly shuts off, the flame sensor may be dirty or malfunctioning. Clean the flame sensor or replace it if necessary.

Frequently Asked Questions


Q: What is the warranty on the Lennox SLP98 furnace?

A: The furnace comes with a limited lifetime warranty on the heat exchanger and a 10-year limited warranty on covered components.

Q: How often should I have my Lennox SLP98 furnace serviced?

A: Lennox recommends annual maintenance on theĀ  furnace to ensure it is running efficiently and to identify any potential issues before they become major problems.

Q: How can I improve the efficiency of my Lennox SLP98 furnace?

A: Regular maintenance, including replacing the air filter and scheduling annual tune-ups, can help improve the efficiency of your furnace. Additionally, upgrading to a programmable thermostat and sealing any air leaks in your home can also help improve efficiency.


The Lennox SLP98 furnace is a top-of-the-line furnace with an impressive AFUE rating.

While it is a reliable and efficient furnace, it can experience some issues from time to time.

By following the troubleshooting tips outlined in this post and scheduling regular maintenance, homeowners can ensure their Lennox SLP98 furnace continues to provide reliable heating for years to come.