Furnace Repair in Reunion, CO

Reunion sits at 5,157 feet, the lowest elevation in this group of Adams County communities, and its 12.6% derate is the smallest correction we apply anywhere out here. That is exactly why the pressure switch catches people out. Homeowners assume altitude only bites in the foothills, then spend a January weekend watching a two-year-old condensing furnace lock out on a draft fault it was never quite built to prove.

What does a furnace pressure switch actually prove?

Not that the inducer motor is spinning. It proves that the inducer is developing a specific negative pressure, measured in hundredths of an inch of water column, across the vent and the heat exchanger. The switch is a safety interlock: no proven draft, no gas valve, no ignition. That is the correct behaviour, and it is why a jumped switch is not a repair but a decision to run a combustion appliance with its flue-blockage protection disabled.

Why does 12.6% still move the switch at 5,157 feet?

Because a fan produces pressure in proportion to the density of the air it is moving. The inducer in a Reunion furnace turns at the same speed as it would at sea level and shifts the same volume, but the air it is shifting is thinner, so the negative pressure it develops at the switch port is measurably lower. The switch setpoint, meanwhile, is a fixed number stamped on the housing. Manufacturers publish altitude-specific switches for this reason, and the 12.6% figure is enough to matter even though Reunion is the lowest ground in this set. Add any real restriction on top of a switch left at its sea-level setpoint and the appliance sits in lockout.

How should the switch be tested instead of jumped?

Put a manometer on the switch port with the inducer running and read the actual negative pressure the furnace develops. Compare it against the setpoint printed on the switch body. If the developed pressure clears the setpoint but the switch contacts never close, the switch has failed. If the developed pressure falls short, the switch is doing its job and the fault is upstream: a blocked vent or intake, a cracked or disconnected hose, a plugged pressure tap, a condensate trap holding water, or an inducer wheel loaded with debris. Two readings and the argument is over.

Does a master-planned community change the failure list?

It narrows it usefully. Reunion is a master-planned community in north Commerce City, which means the housing is comparatively recent and the furnace population skews heavily toward sealed-combustion condensing units with plastic intake and exhaust piping and a condensate trap in the draft path. That combination puts three of the most common Reunion lockout causes on the same subsystem: a frozen or blocked termination, a trap full of standing water, and a hose that has hardened and split. On an older atmospheric furnace those failures do not exist in the same form.

What should a homeowner check before calling?

Look at the two plastic pipes outside and make sure neither is drifted over, screened by ice or blocked by a nest. Check that the furnace filter is not collapsed against the return. Note the flash code on the control board through the sight glass and count it, because a draft-proving fault and an ignition fault are different repairs and the board already knows which one it saw. Beyond that, stop. The gas side is not homeowner territory.

How does Reunion compare with the highest ground MoJo covers?

It is the shallow end of a range that gets steep quickly. Reunion at 5,157 feet carries a 12.6% correction; the highest community we service in this set sits 1,106 feet higher and carries 17.1%. That is a 4.5 percentage point spread on the same appliance, which on a 100,000 BTU/hr furnace is 4,500 BTU/hr of input. It is worth knowing when equipment gets moved between properties, or when a contractor quotes from experience gained in the foothills and applies it to a Reunion address, or the other way round.

Who permits furnace work at a Reunion address?

Reunion addresses fall inside Commerce City rather than being unincorporated, so furnace replacements and vent alterations are permitted through the city rather than directly through Adams County. We confirm the authority having jurisdiction for the specific address before pulling anything, because the boundary in this part of the county is not always where people assume.

Where else near Reunion does MoJo work?

We cover Commerce City, which shares Reunion's 5,157-foot elevation and identical 12.6% derate, along with Central Park and Park Hill to the south. MoJo Home Services has been on these roads since 2009. Call 720-807-4050.

Other Reunion-area pages

If you are comparing notes with someone a town over, we cover furnace repair in Commerce City, furnace repair in Park Hill, furnace repair in Central Park, furnace repair in Saddle Rock Ridge, furnace repair in Tallyn's Reach, furnace repair in Thornton, furnace repair in West Pleasant View, furnace repair in Westminster too.

If it is the other system acting up instead, start at AC repair in Reunion.

More on the service itself: furnace repair.