Furnace Not Kicking On When Temp Drops

Having a cozy indoor temperature during the wintertime is bliss: you can get all cozied up on the couch with your family and enjoy a peaceful evening, watching the blizzard outside rage about. But what happens when suddenly that comfort is gone in a snap? If your furnace isn’t kicking on when the temperature outdoors drops, this blog is for you.

No matter what time of the day it is, you can count on Mr. Furnace Heating and Heating for all your repair needs! That’s right–we’re available 24/7/365 days a year including after-hours, weekends, and holidays at no additional cost! Book your appointment with a certified HVAC technician today!

Why Does My Furnace Stop Working When It Gets Really Cold?

If you’ve ever experienced a real cold snap (and we mean a real cold snap) then you know how bad it can potentially be if your home’s internal heating system shorts out. Pipes freezing, ice damming, power outages - the whole deal. It can be really bad for a property if the issue persists, since the frigid temperatures can (with time) cause significant structural damage to your home, which can wind up costing you tens of thousands of dollars.

If your furnace has suddenly ceased working when it gets cold, it may be due to a number of reasons. Many of these are easily fixed by troubleshooting, whereas others require the intervention of an HVAC technician. At the bottom of the page, we’ll provide some of the most common reasons why a furnace might malfunction, what you can do, and when it’s time to call in the “big guys” - aka the techs!

Why Isn't My Heat Kicking on Automatically When The Temperature Drops?

One of the most common reasons for a furnace not kicking on automatically is simply that the thermostat is not turned on, or it’s not active. The switch is easy to knock into an off position. However, if you’ve already checked the thermostat and that doesn’t seem to be the cause of the issue, there might be a larger problem at hand. You’ll want to do the following troubleshooting:

Check to see if the gas is turned on (someone working on the furnace might have closed the valve by accident.)
Check other gas appliances in your home. If they aren’t working, this could be because there is a gas leak, blockage, or break in the line. Call 911 if you suspect a gas leak, as this can be life-threatening.
Check to see if the furnace is switched on. Locate the power switch and check it.
Replace any dirty air filters.
Clean the ignition sensor (shut off the furnace before you do this.) If you don’t want to DIY this, call a technician.
If all else fails, call a technician to diagnose the problem.

Why is my furnace not responding to the thermostat?

While seemingly straightforward, start by checking if your thermostat is indeed switched on. It's a step often overlooked by homeowners who might panic and call immediately for a technician when the solution could have been as simple as addressing the thermostat. This component of your heating system is tasked with gauging room temperature and subsequently initiating the furnace to sustain a comfortable and constant temperature.

For programmable thermostats, ensure that the display is active, the furnace is operational, and the setting is adjusted to "heat." If your thermostat is manually operated, it's easy for the switch to inadvertently turn off during cleaning or other household tasks. Therefore, verify that the thermostat is switched on.

However, in the event that the thermostat remains unresponsive or your furnace fails to react to thermostat adjustments, this could point to a larger underlying issue necessitating professional attention.

5 Top Reasons For a Furnace Malfunction:

Dealing with a malfunctioning furnace during the cold winter is an uncomfortable situation that nobody wants to face. Below are several reasons why your furnace might not be activating automatically. While you can resolve certain issues on your own, others might necessitate the assistance of a technician. It's recommended to begin with the simpler troubleshooting steps before considering a professional's help.

Reason 1: Soiled Ignition Sensor

The ignition sensor serves as a safety mechanism that detects gas combustion in your gas furnace. By gauging temperature increase, it identifies flames and prevents unburned gas leakage. An accumulation of residue can impede the flame sensor's efficacy. While cleaning the ignition sensor is feasible as a DIY task, you can also opt to enlist professional assistance if you find the process challenging.

Reason 2: Gas Supply Interruption

This issue is more intricate and typically necessitates professional intervention. With a gas furnace, the problem could lie with the gas supply, specifically the gas valve. If this is the case, the furnace won't ignite even when the thermostat signals for more heat.

Reason 3: Dirty Air Filters

When your air filters or furnace filters take on a grey and fuzzy appearance, it's a sign that they're due for replacement. If these filters become excessively dirty, they can obstruct airflow, leading to heat accumulation in the heat exchanger. As a result, your furnace might cease functioning altogether. A built-in limit switch triggers when the temperature reaches a certain point, causing the furnace to shut down. To ensure optimal performance, replace furnace air filters every 1-3 months.

Reason 4: Thermostat Malfunction

A dysfunctional thermostat fails to communicate the furnace activation signal. It's important to check if the thermostat responds and accurately displays the current temperature. A simple solution might be turning the thermostat off and then back on.

Reason 5: Blower Motor Complications

A malfunctioning blower motor, responsible for circulating air through your HVAC system, can lead to furnace start-up failure or rapid shutdown. This can stem from a buildup of debris and dust or the motor's deteriorating efficiency due to aging and wear.

Is your furnace on the fritz? If so, book a furnace repair appointment with the certified HVAC team at Mr. Furnace today! We’re available 24/7/365 days a year including after-hours, weekends, and holidays at no additional cost!