Pressure switch open with inducer on professional#
Pressure switch open with inducer on series#

You can tell the system is on some sort of safety lockout when the furnace’s fan (or blower) pushes room temperature air through the ducts and into your rooms. If the pressure switch doesn’t close after 3 to 5 tries, the control board will stop sending voltage to the inducer motor, essentially locking it out from attempting it anymore. If the pressure switch doesn’t activate, the furnace will then shut down, wait a bit, and try again. Within 5 to 7 seconds in most cases – and the rest of the furnace starts up from there. The inducer motor creates this draft quickly.

If the inducer turns on and is working normally, the furnace pressure switch should activate. The pressure switch is a normally open switch that closes upon the manufacturer’s specifications for required negative pressure. Next, a safety device called a pressure switch activates when the diaphragm inside it recognizes the inducer motor’s suction or purging action. Next Up, the Furnace Pressure Switch Activates When we have cleaner air inside the heat exchanger at the time of combustion, the furnace’s efficiency increases. It makes the air inside the hollow tubes of the heat exchanger cleaner when the flame kicks on. It’s a safety feature that creates a negative pressure or draft which purges the heat exchanger of any poisonous gasses, namely the byproducts of combustion. This starts the inducer motor for up to 60 seconds before anything else even happens. 120 volts is applied through the wires coming from the control board. When a furnace begins a new cycle, the inducer motor is the first thing you should see kick on. The blower forces air through the ducts.Flame sensor proves all burners are lit.

Pressure switch proves the inducer operates correctly.

It’s very straightforward, and you should have this memorized before you can even consider being qualified to troubleshoot. The Furnace Sequence of Eventsįirst, as a technician, you must know the sequence of events for a gas furnace to start properly. An actual flame produced by the ignition and start-up of a gas furnace can cause severe burns and damage to a person or property. The furnace also produces hot surfaces within the furnace compartments and around the housing, which can cause severe burns. There are also lots of moving components that can damage body parts-namely, hands and fingers. There are high and low voltages that can shock a person.

Pressure switch open with inducer on professional#

Fox Family Heating & Air does not recommend anyone other than a professional to start opening the furnace up and trying to diagnose the failure going on with your system. This video is for educational purposes only.

That’s coming up here on the Fox Family Heating & Air Blog.įirst, I want to give fair warning to anyone watching this that is not already an experienced technician in the HVAC industry. And to wrap things up, I’ll give you five easy things to check when you’re troubleshooting a furnace pressure switch. I’ll fill you in on what the pressure switch does and why it’s important.

Pressure switch open with inducer on series#

I want to expand on our recent gas furnace troubleshooting series by going into each part of a furnace’s operation sequence. Today we’re going to talk about troubleshooting a furnace pressure switch.