Published by bbbplumbing on

Why does my high efficiency furnace frequently stop working in cold weather?

There are many reasons explaining why your furnace frequently stops working, particularly in extremely cold air due to the venting of the furnace. There are two common reasons for this issue, they include:

  1. The most common cause of a furnace not functioning properly, is due to a need in a new air filter; which usually needs to be changed every 2-4 months, and a cleaning of the flame sensor.
  2. Another common cause, and a more complex problem is having an incorrect Venting system termination.
How should a venting system be done, to avoid failure in cold winter weather such as the freezing Calgary winters?

It is very important that your venting system is terminated to code. The exhaust pipe has to have a slope or grade at least 2% towards the furnace. The reason is to let the condensation water to be flushing toward the floor drain or to a condensation pump. It is fine if you don’t understand this information as your technician will always help you understand.

You may also read more here:

How should the venting system be terminated?

The combustion air intake (Intake for only the furnace) must be a minimum of 12’’ above the ground by a 90 fitting facing the ground. The exhaust must be at least 12’’ vertically from the combustion intake, and should be fitted with a 90. With this system, there will be no chance that the combustion intake will take in the exhaust output. Otherwise the exhaust will get back into the furnace, and turn it off.

Another small point for venting termination is to avoid pipe freezing. If the exhaust pipe is terminating more than 2’ outside for Alberta and 3’ outside for BC in outside, it must have proper pipe insulation to avoid freezing.

Categories: Heating

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