Pioneers Heating & Air

Heating Repair in Pasadena, CA

Heating Repair

Project Description

We were called to a home in Pasadena, CA, that had problems with their furnace. The homeowner noticed cold air coming out of the vents instead of releasing heat. Our technicians arrived on time to diagnose the problem and found that it was caused by a faulty pressure switch. Within a few minutes, we replaced it inexpensively and at no extra labor cost. During this heating repair, we took great care to save the homeowner’s preferred temperature settings on their thermostat. And in no time, it was fully operational again. Before leaving, we tested and ensured it worked well. Another satisfied client served by Pioneers Heating and Air!

Complex machines, like furnaces, have many components that work together to ensure optimal performance and safety. One such component in a furnace is the pressure switch. It works with the control board to keep your furnace operating safely. However, when the pressure switch fails, your furnace will not work. That is why knowing how to troubleshoot pressure switches when they fail is important.

What is a Furnace Pressure Switch?

Close to the furnace motor is an automatic safety feature called the pressure switch. Its purpose is to shut the furnace down when it senses negative pressure. That happens when the draft inducer motor is running and creates negative pressure. Backdrafting can be dangerous because it reintroduces exhaust fumes into the system. Additionally, the pressure switch protects against gas leaks and disables furnace cycling in the event of a mechanical malfunction.

Types of Pressure Switches

When it comes to pressure switches, you have a few different options. For example, single-stage furnaces need one pressure switch, while two-stage units need a high and low-pressure switch to handle the first and second heating stages. In regular furnaces, there are typically four or five different pressure switches. These are placed at different points in the furnace. For condensing furnaces, a typical setup is three pressure switches — but there can be as many as six.

The Causes of Pressure Switch Failures

False tripped pressure switches are a leading cause of furnace malfunctions. Although pressure switches do not typically break down, they may act up because of one of these reasons:

  • Age of the pressure switch
  • An outdated pressure switch can cause inaccurate readings and faulty furnace cycling
  • Coated or stiffened pressure switch diaphragm


If the diaphragm is coated or stiffened, this can also be a problem. You can fix this issue by tapping on the casing, but a repair may be necessary sooner rather than later. If you notice a “flapping” noise, similar to a flat tire, the diaphragm is likely busted and must be replaced with a new one.

Blockage in flue/chimney

Blockages are one of the most frequent causes of furnace pressure switch problems. That includes a blocked flue pipe, which may not occur during the winter when your system is operational. Check the flue every year before turning on the heater and remove any obstructions that may interfere with the switch. The port leading to the collection chamber can also become clogged over time. It will cause problems with the switch if it becomes clogged.

Brittle pressure switch hose

The pressure switch hose can also cause two other problems. One example is a damaged hose. It could be brittle due to age or have a hole, but it is easily replaceable. The hose may also fill with water due to moisture caused by heat that travels down the flue and into the pipe. You take the hose out of the port to drain or inspect it for possible problems.

Testing and Replacing Pressure Switch

When troubleshooting your pressure switch, turn the power off before testing it. That will prevent any risk of electrical shock or damage to the system. Replacing a pressure switch is a simple HVAC service that can be completed in less than 10 minutes, provided you can access the furnace and a few basic tools. 

When you are unsure about handling electricity or lack the necessary skills for a repair, it is time to call a technician. An HVAC technician has the skills and knowledge to test switches and catch any potential problems safely. So, rather than attempting a repair, it is best to call for professional heating maintenance  services.

HVAC Repair Near Me

What else can you do when your furnace is blowing cold air? Our Pioneers Heating and Air experts can help you with your heating and air needs. From pressure switch replacement to furnace repair, we have you covered. Whether you need a quick fix or a long-term solution, we are here to help. Our expert technicians can service all makes and models of heating and air conditioning units. In addition, we are BBB-rated, so you can be sure that your repairs are done right. Contact us today at (626) 217-0559 to get started!

Project Gallery


E Del Mar Blvd Pasadena, CA, US, 91107

Powered by