Pilot Light and Ignition Repair in Fort Collins

Pilot light and ignition repair in Fort Collins runs $200 to $400 installed for a thermocouple or thermopile, $300 to $600 for a full pilot assembly, and $350 to $700 for an electronic ignition module. These are the most common gas fireplace repairs in Larimer County, they are measured with a millivolt meter rather than guessed, and on a standing-pilot unit the part is usually on the truck.

If you smell gas at any point while trying to light the pilot, stop, leave the house, and call Xcel Energy or 911 from outside.

Why pilots fail in October

Fort Collins fireplaces sit cold from April to October and then run hard. The Colorado Climate Center’s station on the CSU campus puts the 1991-2020 January normal at a 45.0 degree high and an 18.3 degree low, and the normal snowfall for October through January alone is 26.1 inches. Six months of dust settles into the pilot hood. Spiders build in the pilot tube and the venturi. The thermocouple tip oxidizes. Then the first cold night, you turn the knob and hold, the pilot lights, you let go, and it dies. Or it holds, but the wall switch does nothing. The week after the first hard freeze is the busiest week of our year for exactly this reason, and a September annual service is how you skip that line.

Two ignition systems, two repairs

Every gas fireplace in the county uses one of these, and knowing which one you have (a pilot that burns all the time, or one that sparks when you turn it on) is the first triage question.

Standing pilot, millivolt system

The pilot burns continuously. In its flame sit two sensors:

• The thermocouple generates a few millivolts, just enough to hold the electromagnet in the gas valve that keeps the pilot gas flowing. When it weakens, or the flame is too weak to heat it, the magnet lets go and the pilot dies the moment you release the knob.
• The thermopile is a stack of thermocouples that generates roughly 300 to 750 millivolts open circuit. That is what the wall switch, thermostat, or remote uses to open the main burner valve. Below about 300 millivolts under load, the valve will not open no matter how many times you flip the switch.

The diagnosis is a meter reading. We measure the thermopile open circuit and under load, check the pilot flame envelope on both sensors, and test the switch and wiring by jumping the valve terminals. A thermopile reading 200 millivolts with a good pilot flame gets replaced. A thermopile reading 600 with a dead switch gets a new switch, at $150 to $400 instead of a thermopile you did not need. A pilot that cannot be cleaned back to a sharp blue flame that wraps both sensors gets a new pilot assembly, which on most units includes the hood, the tube, the thermocouple, and the thermopile as one part.

Common valves on these systems are Honeywell, SIT, Dexen, and Robertshaw. Some have a built-in piezo igniter for the pilot; on others you light it with a long lighter through the access hole.

Intermittent pilot ignition (IPI), electronic

No standing pilot. When you turn the unit on, a control module sends high-voltage spark to an electrode at the pilot hood, opens the pilot valve, and waits for a flame sensing rod to prove the pilot exists by rectifying a tiny current through the flame. Once proved, the module opens the main valve. Between fires, the pilot is off. Power comes from a wall transformer, with a battery backup pack for outages.

Failures, in order of how often we see them:

1. Dead batteries. In the backup pack or the remote. Free to fix, and worth checking before any call.
2. Clicks but no flame. Gas valve closed at the wall, a fouled or cracked spark electrode, a blocked pilot orifice, or a module not opening the pilot valve.
3. Lights, then drops out after a few seconds. The flame sensing rod is dirty, mispositioned out of the flame, or the ground path is bad. The module thinks the pilot failed and shuts down for safety.
4. Lockout. After a few failed tries most modules lock out and need power cycled. That is a symptom, not the fault.
5. Module failure. Diagnosed by elimination, after the electrode, rod, and gas supply are verified. Brand sets the part price; this is the $350 to $700 range.

Newer homes in Timnath, Wellington, and Windsor’s post-2010 phases are almost all IPI. The 1990s and 2000s direct-vent units in south Fort Collins and Loveland are mostly millivolt.

Altitude and the pilot

At 4,997 feet, a pilot flame is smaller and softer than the same pilot at sea level. On a unit that was never derated, the main burner runs rich and the pilot can still be marginal on its own, especially on the propane cabins around Estes Park at 7,743 feet where the derate is well over 20 percent. A pilot flame that only just licks the thermocouple tip will hold in September and quit in January when the cold draft through the vent pulls it sideways. Part of every pilot repair is setting the pilot flame envelope and checking the manifold pressure against the manufacturer’s figure for the elevation.

How the visit goes

1. Model number and symptom by message, so the right pilot assembly or module rides out.
2. Leak check with a combustible gas detector at the valve, the pilot tube, and the flare fittings. CO check.
3. Millivolt readings, flame inspection, switch and remote test. On IPI, spark and flame-sense checks.
4. Clean the pilot assembly and burner ports. Vacuum the logs. Half of “pilot will not hold” calls end here.
5. Replace the thermocouple, thermopile, pilot assembly, electrode, sensing rod, or module.
6. Set the pilot flame, test-fire, verify shutdown, and write down the readings for you.

What it costs

The pricing page has the rest of the table, including the gas valve that a good tech only condemns after the pilot and thermopile pass. If a bidder quotes a valve without showing you a millivolt reading, ask for the reading.

We relight and repair pilots across Fort Collins and out to Loveland, Windsor, Timnath, Wellington, Greeley, and Estes Park. Send the rating plate and tell us whether the pilot burns all the time or sparks on demand.