Package unit systems are common in areas where houses don't have the space for traditionally split HVAC units. Unlike split systems that use an outdoor condenser and indoor air handler, package units bundle your AC equipment, air handler, and furnace into a single outdoor box. If your home uses one of these systems for heating, there can be some subtle differences in the problems you may face.
However, if your package unit includes a gas furnace, it will still use an inducer blower. The inducer creates negative pressure ("draft") that pulls exhaust gases away from the combustion chamber. Keep reading to learn about three potential problems that may develop with the inducer blower on your package unit furnace.
1. Faulty Pressure Switch
The pressure switch is your furnace's first line of defense against a failing inducer. This switch attempts to prove that your furnace is producing an adequate draft by testing the pressure in the exhaust channel. If the pressure switch does detect this draft, it will prevent your furnace from igniting the burners.
While the pressure switch is a critical safety feature, it's also a potential failure point. A faulty switch will generally "fail safe," which means it will fail in a position that stops your furnace from operating. Never attempt to bypass a faulty inducer switch. Instead, have an HVAC technician or heating repair professional test your switch and replace it, if necessary.
2. Clogged Pressure Tube
The pressure switch typically isn't installed on the inducer motor but connects via a flexible tube. This tube allows the switch to "sense" the pressure created by the inducer, allowing it to shut the furnace down if the inducer isn't working. While this tube rarely clogs with indoor units, debris can more easily enter an outdoor package unit and cause this tube to become gunked up.
The good news is that a clogged pressure tube is a relatively straightforward and cheap fix. However, your furnace will generally show similar symptoms to a faulty pressure switch, so you should still allow a professional to diagnose the problem. If a clogged tube is to blame, a simple replacement will get your furnace running again.
3. Inducer Wheel Rust
The inducer blower uses a metal wheel similar to your main house blower. Although the combustion chamber is sealed, an outdoor package unit is still more likely to suffer exposure to varying amounts of humidity. As a result, the metal inducer motor housing and wheel can rust and eventually begin to rot and break apart.
Inducer wheel rust can cause the inducer to seize or simply result in poor sealing and the inability to create sufficient draft. Either way, the pressure switch will detect the problem and prevent your furnace from running until you replace the inducer.
My name is Maura, and I am certified in HVAC installation and repair. I have many clients who call me in a panic because they have turned on their air conditioners and nothing has happened. Your air conditioning technician will get to you as soon as possible, but there are some steps you can take while you are waiting. You might just find that you are able to fix the problem on your own, although you will still want to have a professional assess the situation. In this blog I will take you through some common reasons your air conditioner might not be working and show you some easy temporary solutions.