What You Should Know About Furnace Boiler Puffbacks

19 Jan by Will Kruse

What You Should Know About Furnace Boiler Puffbacks

A furnace or boiler that works properly is important for your home, especially during the cold months. Unfortunately, there are times when it’s not working as well as it should be.

In these cases, you may experience a puff back or backdraft. You may even have a furnace or boiler that won’t run at all. In this article, we’ll discuss what causes these problems and how you can resolve them.

What is a Puffback?

A puff back is a short-term, temporary flame that occurs in the combustion chamber of a boiler.

The term “puff back” is used to describe the event when the flame becomes visible inside the furnace. The flame burns for a moment and then disappears as quickly as it appears. A puff back may also be referred to as a “flashback,” but this term is typically reserved for cases with more than one ignition source in the same area.

Puff backs, or explosions within a heating system, can cause significant damage. A large puff back may send smoke and soot throughout a house, while even a small one may destroy the furnace’s internal components.

It can also cause damage to the walls and ceilings of the room where the furnace is located. Puff backs can be a safety concern because they can cause fires and other damage if left unchecked.

What Causes a Puffback?

Puff backs result from incomplete fuel combustion or improper operating conditions within the furnace. This can include:

  • An overheated boiler or furnace
  • A ruptured pipe, connection, or tubing (an obstruction could cause this)
  • A leak in the system (like with a cracked expansion tank)
  • A defective pressure switch
  • A malfunctioning blower motor or fan
  • A defective cyclone separator
  • A damaged fuel pump or lines to the furnace
  • A problem with the thermostat (like a worn-out contact)

How Do You Prevent Puffbacks in Your Furnace or Boiler?

Furnace and boiler puff backs are the most common form of boiler failure. They occur when the pressure in the system exceeds normal operating levels and causes a sudden release of steam or gas into the air.

Puff backs can be dangerous and potentially fatal, so it’s important to know how to prevent them in your furnace or boiler. Below are some tips on how you can do just that:

  1. Oil Your Furnace or Boiler Regularly

    Ensure you’re using high-quality oil that meets industry standards when servicing your furnace or boiler. You should also get regular maintenance checks to ensure that all parts work properly and safely.

  1. Have Your System Inspected by an Expert

    If you suspect something is wrong with your system, don’t wait until it’s too late! Get it checked out as soon as possible by an expert who can determine whether any issues with its design or operation need addressing before they become more serious problems down the road.

  1. Clean and Maintain Your System Regularly

    The best way to keep your heating system running is to ensure it’s clean and well-maintained. This means checking the filters regularly and replacing them as needed, keeping the pipes clean of debris or corrosion, and ensuring that all parts function properly.


While furnaces and boiler puff backs can be potentially dangerous, the best defense is a good offense. Paying attention to your system’s operational patterns can catch the tell-tale signs of a developing puff back before it becomes a problem. As always, we encourage people to take an active interest in the comfort and safety of their homes, and with these tips on spotting puff back, you’ll be much more likely to protect yourself against this common issue.

If you ever need a heater repair, contact L.J. Kruse Co. today. We provide service to all makes and models of heating equipment, and we’ll get your system back up and running in no time!

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