One of the most common and simple causes of an overheating furnace is poor air circulation. The internal components of your furnace can get too hot when there isn’t good airflow. This usually happens when you forget to change your air filter regularly.

How do you fix a furnace that overheats?

How to Reset Your Furnace

  1. Turn down the thermostat to its lowest setting.
  2. At the circuit breaker, turn off the power to the furnace.
  3. If this is a gas furnace, turn off the gas supply at the valve for the main gas pipe, but leave the pilot’s gas supply on.
  4. If the pilot light was out, light a match to relight it.

What happens if furnace filter is in backwards?





When a furnace filter is placed backwards, the fibers can’t do their job properly. This means your furnace has to work harder to generate the same air flow, resulting in increased energy costs. Particles are also allowed to build up irregularly, making the furnace working even harder to draw air.

Can my furnace handle a MERV 13 filter?

MERV 13 is the highest MERV value safe for residential furnaces; the higher ratings are used primarily in commercial units. If you are wondering what MERV to try, keep these recommendations in mind; ASHRAE recommends MERV 6 or higher. US Department of Energy recommends MERV 13.

Can I use a thicker filter in my furnace?

Most air filters are 1 inch thick, but some systems can accommodate filters 2 to 5 inches thick. In our tests, we found that the thicker the filter, the better it works and the longer the replacement intervals. That means it’s better for you and for your heating, ventilating, and air conditioning (HVAC) system.

What would cause a high temp rise on furnace?

If the temp rise is too high, it could be caused by an oversized furnace, undersized ductwork, a combustion problem, or an airflow obstruction. Airflow obstructions can be caused by a dirty furnace filter, a dirty air conditioner coil, a dirty secondary heat exchanger, or blocked supply or return registers.

What causes a furnace blower motor to overheat?





If your furnace blower motor is overheating, the best thing to do is turn off the unit and check the air filter and vent ducts. A clogged air filter or vent could be causing the blower motor to overheat due to airflow restriction. Try to replace the air filter to see if this fixes the issue.

What happens if your furnace filter is too big?

If the filter is too big, then it won’t fit into the filter slot and you won’t be able to put the cover back on. This can cause dirty air to infiltrate the inside of your furnace (and home).

Can a furnace filter be too tight?

A furnace filter should fit snug inside of your unit. If it is too loose, then air will still come in even while your furnace is running. On the other hand, if it is too tight, you may not be able to remove the filter when it is time to change (if that’s what you decide).

Do higher MERV filters restrict airflow?

Wrong. While the highest MERV ratings are the most effective for air quality, they can harm your HVAC system. A higher MERV rating means a higher resistance, which means less airflow.

What is the typical temperature rise for a standard efficiency gas furnace?



The answer is 35°F TO 70°F. The temperature rise for a high-efficiency furnace is quite low. Even for conventional furnaces, 70°F to 100°F is the range.

What is the normal temperature rise of a furnace supposed to be?

With a conventional gas furnace, you should be at about 140°F-170°F at the supply plenum. A high efficiency furnace will be lower, around 110°F-140°F. However, the temperature at the outlet of the furnace, is dependent on the temperature of the incoming air.

Is it normal for furnace to be hot to the touch?

Most single stage furnaces should be just uncomfortable to touch on the main trunk just above the main unit. As Heat rise levels can range from 50-70 higher than ambient air temp. Yes, it’s normal.

Can my furnace explode?



The short answer is yes, it is possible for your furnace to explode. But it is highly unlikely especially with the build of modern furnaces, which include high safety standards to decrease the risk of an explosion.

Why does it smell like burning from my furnace?

As your furnace heats back up it is burning this dust off, hence the burning smell. This is normal and is not considered to be a safety hazard. The smell should go away after a few hours once the furnace burns all the dust away.

What does a cracked heat exchange look like?

In most furnaces, you can see the flame that heats your air. Remember: blue is normal, orange or yellow is not. Audible Sounds. If you have a crack in the heat exchanger, you are likely to hear a rattling noise as your thermostat turns on the heat.

Why would a heat exchanger overheat?

Cracked Heat Exchanger Causes
The filter, coils, and blower get clogged, and the air cannot flow as it should. Air is needed to maintain the internal system temperature and absorb excess heat. With the airflow blocked, the internal temperature increases. This overheating can, in turn, cause the heat exchanger to crack.

How do I know if my heat exchanger is clogged?



A Pungent Odor
This smell will most likely be a sulfur-like smell or burning rubber smell due to soot or corroded polypropylene in the tubes of the blocked secondary heat exchanger. You might notice this odor leaking inside your home near the furnace – if the heat exchanger is significantly blocked.