My furnace turns on then shuts off after a minute. What causes that?
That pattern is called short cycling and the most common cause is a dirty flame sensor, which stops proving the flame and shuts the burners down as a safety response. Other causes are a clogged filter restricting airflow, a failing limit switch, or a blocked flue. A flame sensor clean or replacement is usually an inexpensive same-visit repair.
Why does my furnace blow cold air?
If the blower runs but the air is cold, the burners are not staying lit or are not igniting at all. Common causes are a cracked igniter, a dirty flame sensor, a gas valve issue, or a tripped high limit. If the thermostat fan setting is on ON rather than AUTO, the blower simply runs between heating cycles, which also feels cold at the vent.
Is a cracked heat exchanger really dangerous, or is that a sales tactic?
It is genuinely dangerous, because a cracked heat exchanger can put combustion gases including carbon monoxide into the air you breathe. It is also one of the most abused claims in this trade. We show you what we found and why we reached that conclusion, and we would rather you get a second opinion than take our word for a replacement that size.
Should I repair or replace my furnace?
If the unit is under roughly 15 years old and the failure is an igniter, flame sensor, blower motor, inducer or control board, repair almost always makes sense. Past 15 to 20 years, or with a failed heat exchanger, replacement usually costs less over the remaining life than a series of repairs. You get both numbers and you decide, not us.
Do furnaces need to be set up differently at Colorado altitude?
Yes. Gas appliances have to be derated for altitude, which means the burner orifices and gas pressure are set for the thinner air at Front Range elevation. A furnace left at factory sea-level settings runs inefficiently and can soot up. We check and set this on every install and on repairs where it looks wrong.
How fast can you get out when the heat is off?
Often the same day when the schedule allows. Call or text (303) 601-1444 early in the day for the best chance at a same-day slot. We answer until 9 PM, seven days a week.