Your furnace has given up, leaving your Glenn Heights home freezing cold, but you can’t see anything physically wrong with the unit. You may be one of many local homeowners whose furnace pressure switches have failed this winter.
What happens when a furnace pressure switch goes bad? Learn the answer in our furnace troubleshooting guide, then call us for heating services in Glenn Heights, TX.
Understanding Your Furnace Pressure Switch
What is a furnace pressure switch, anyway? It’s a safety feature that constantly scans for exhaust and gas fumes from combustion. If this exhaust re-enters the system, it can cause the unit to shut down. And if gas fumes enter your home’s air, it’s a serious fire hazard. On top of that, your family is at risk of carbon monoxide poisoning.
What Is Back Drafting?
Your furnace burns fuel to create heat energy, but this process isn’t 100% efficient. Some of the fuel burnt turns into exhaust gas, which is why the process is called incomplete combustion.
Normally, your furnace routes dangerous gas through the vent and out of your Glenn Heights home. But if there’s negative air pressure, exhaust gasses get sucked back inside the system. This is called back drafting. If you suspect back drafting, it’s unsafe to turn the furnace on. Call an expert for help right away.
What Happens When a Furnace Pressure Switch Goes Bad in Glenn Heights?
Furnace pressure switches work by sensing negative air pressure. If all is well with your switch, it will close automatically when it detects a change in air pressure.
But what happens when a furnace pressure switch goes bad? In this case, the switch remains open, and the furnace will quit the startup process, causing heating disruption for a few minutes. The furnace will then try to restart three to five times, depending on the model. If the switch still won’t engage, your furnace will go into safety lockout mode. You won’t be able to use the unit until you fix the problem.
In some furnaces, it’s easy to tell whether the pressure switch has gone bad. Many modern furnaces have an LED panel that displays error codes. Cross-check the error code you’re seeing with the user manual.
If your furnace lacks an LED panel, you’ll have to rely on your ears instead. Stand close to the furnace and wait for it to try to start. You should hear a clicking noise right after the fan kicks on. If you don’t hear it, the pressure switch has probably failed.
Top Causes of a Furnace Pressure Switch Malfunction
Now that you know what happens when a furnace pressure switch goes bad, what causes the switch to fail?
One of the main reasons why furnace pressure switches fail is a blockage somewhere in the system that affects air pressure. For instance, you may have a soot blockage in the collection chamber port. Blockages in the chimney and flue are common as well. Birds and other critters love to build their nests in chimneys. The hose connected to the pressure switch may also have become clogged with water.
There could also be something wrong with the inducer fan, such as a motor blockage. Repairing the fan may get your furnace back up and running again. However, inducer fans often fail when other components in the furnace stop working. For example, the fan gets signals from the furnace’s control board, so if the board quits, so will the fan. Replacing the control board can be expensive, so you may opt to retire the furnace instead.
The problem may be something as simple as dirt buildup on the pressure switch. If there’s a lot of dirt and dust on the switch, it can’t sense the pressure accurately. Cleaning the switch may do the trick.
Lastly, many pressure switches fail simply because of old age. If this is your problem, it’s a safe bet that your furnace is on the older side, too. You may want to think about replacing the unit with a more efficient one. Modern furnaces cost less money to run and heat your home much more evenly than outdated models.
Wondering What Happens When a Furnace Pressure Switch Goes Bad? Call Our Experts in Glenn Heights, TX
What happens when a furnace pressure switch goes bad? You’ll have a furnace failure, leaving you out in the cold. When this happens, count on Dial One Johnson Plumbing, Cooling & Heating for all your repair needs. Call us to schedule furnace troubleshooting or keep reading to learn about the importance of scheduling furnace maintenance.
