What happens on furnace install day

A straight furnace swap takes a day. Ask for the numbers the crew records at startup.

Before the crew arrives

• Clear a path from the door to the furnace and about 3 feet around it, so the old cabinet comes out without scraping walls.
• Know where the floor drain is.
• Plan on the heat being off from morning until startup.

Swapping the furnace

1. Gas and power go off. The old furnace and its vent pipe come out.
2. The new furnace is set level on the return, with a new transition up to the coil and supply duct.
3. The vent goes in: PVC through the wall or roof for a 96% furnace, or the metal vent reconnected and the chimney checked for an 80%.
4. The gas line gets a shutoff and a sediment trap, then a leak test.
5. The condensate trap is filled and piped to the drain or a pump.
6. The thermostat is wired, along with the AC controls if there is a coil.

Startup numbers to ask for

• Gas pressure and burner orifices, set for Denver's altitude, with the input checked.
• Temperature rise across the furnace, inside the range on its label.
• Combustion readings in the flue, including carbon monoxide.
• Static pressure in the ducts.

Keep these with the manual, the model and serial numbers, and the filter size. They tell the next technician how the furnace ran on day one.

Permit and inspection

Every furnace replacement needs a mechanical permit. A city inspector checks the gas, the venting and the combustion air after the install.

Send photos of your furnace or schedule an estimate.