The house is getting colder and nothing you try brings the heat back. Call HVAC Sioux City: tell us what you’re seeing and a licensed local heating technician can come out.
No heat? Do these three things first
A furnace or boiler that won’t heat is stressful, especially after dark in January. Take a breath: most no heat calls are one failed part, and you have time to do this in order.
1. Rule out a gas or CO problem
If you smell gas or a carbon monoxide alarm is going off, stop here: get everyone outside and call the gas utility or 911. Everything else can wait. Our emergency page has the full steps.
2. Run the quick checks
- Thermostat on Heat, set five degrees above room temperature, display working.
- Power switch at the furnace or boiler on; breaker not tripped.
- Furnace filter not clogged; front door panel pushed in tight.
- High efficiency furnace vent pipes outside clear of snow.
- Boiler pressure gauge reading in its normal range (often marked on the gauge).
3. Protect the house and call
If the heat isn’t back in a few minutes, call us. While you wait, open cabinet doors under sinks on outside walls, let those faucets drip, close the blinds, and gather everyone in one room with a safely placed space heater.
What no heat repair covers
“No heat” is a symptom, not a diagnosis. The technician works through the whole system until they find the break.
- Thermostat power, wiring, settings and replacement
- Furnace ignition: hot surface igniters, spark ignition, pilots
- Flame sensors and burner adjustment
- Inducer motors and pressure switches
- Blocked intake, exhaust and condensate drains
- Control boards, transformers and fuses
- Gas valves (gas supply problems go to the utility first)
- High limit and rollout switches that keep tripping
- Boiler circulator pumps, zone valves and low water cutoffs
- Heat pump defrost failures and backup heat strips
Why the heat stops: the usual causes
Match what you’re seeing to the most likely cause. It helps you describe the problem when you call.
| What you see | Likely cause | Can you fix it? |
|---|---|---|
| Thermostat screen blank | Dead batteries, tripped breaker, blown fuse on the furnace board | Batteries and breaker, yes; a blown fuse needs a technician to find why it blew |
| Inducer hums, burners never light | Blocked vent, failed pressure switch or igniter | Clear snow from vents; otherwise call |
| Burners light, then shut off | Dirty flame sensor, poor ground, weak flame | Call |
| Burners run, blower never starts | Blower motor or capacitor failure | Turn it off (it can overheat) and call |
| Radiators cold, boiler hot | Circulator pump, zone valve, air in the lines | Bleeding one radiator, maybe; otherwise call |
| Heat pump blowing cool air | Defrost or backup heat problem | Clear snow from the unit; call |
What happens on a no heat visit
Safety first
The technician checks for gas leaks and venting problems before running anything.
Find the break
They follow the startup sequence from thermostat to burner to blower until one step fails, then test that part.
Heat back on
After going over the repair with you, they fix it and watch the system run full cycles so you know it’s holding.
Many no heat repair calls in Sioux City come down to common parts like igniters, flame sensors and capacitors. If a part has to be ordered, ask the technician what can be done in the meantime to keep the house safe and warm.
Making a no heat night less likely
Sioux City winters will find a weak part sooner or later. These habits push that day further out:
- Have the system checked every fall with a furnace tune up.
- Replace the filter regularly: a clogged filter is the most common cause of overheating shutdowns.
- After every storm, clear snow away from vent pipes and the heat pump.
- Don’t ignore a furnace that takes two tries to light. That’s an igniter or flame sensor asking for attention.
- Keep fresh batteries in the thermostat before winter.
- Know where your furnace switch, breaker and main water shutoff are before you need them.
No heat repair in Sioux City, system by system
Gas furnace
The most common no heat call in Sioux City. Listen at the furnace: a humming inducer with no flame points to venting or a pressure switch; a flame that lights and quits points to the flame sensor; total silence points to power, the thermostat or the control board. Each clue helps the technician arrive ready.
Hot water boiler
If the boiler is hot but the radiators are cold, the problem is circulation: a pump, a zone valve or air in the lines. If the boiler is cold, check its switch and the pressure gauge, then call.
Heat pump
A heat pump that blows cool air in winter may be stuck in defrost, or its backup heat may have failed. Clear snow from the outdoor unit, and if your thermostat has an emergency heat setting, use it until the technician arrives.
Mini split
Ductless units show an error code or blinking light when something is wrong. Note it, check the breaker and make sure snow has not buried the outdoor unit. No heat repair in Sioux City covers all four types, so tell us which one you have.
No heat questions
How cold can my house get before pipes freeze?
There is no single number: it depends on where the pipes run. Pipes in outside walls, crawl spaces, garages and under sinks on exterior walls freeze first, and they can freeze even while the middle of the house still feels livable. On a below zero night with no heat, treat it as urgent: open the cabinet doors under sinks, let faucets on outside walls drip, and call.
The furnace fan runs but there is no heat. What is wrong?
Usually the burners are not lighting or are shutting off right after they light: an igniter, flame sensor or pressure switch problem. Check whether the thermostat fan is set to On instead of Auto first. If it is on Auto and the air is still cold, read the blinking code on the control board and call. More detail on the furnace repair page.
Nothing happens at all when I turn up the thermostat. Where do I start?
Check the thermostat display (dead batteries make it go blank), the furnace power switch, the breaker and the furnace door panel. On a boiler, also check the boiler’s own switch and the pressure gauge. If everything has power and still nothing happens, the problem is in the controls and needs a technician.
Is it okay to use the oven to heat the kitchen?
No. A gas oven or range used for space heating can produce carbon monoxide, and it was never designed to run for hours with the door open. Use a properly placed electric space heater, close off unused rooms, and keep everyone in the warmest part of the house until the heat is back.
Why did my heat go out right after a snowstorm?
If you have a high efficiency furnace, drifting snow has probably blocked its plastic intake or exhaust pipe on the side of the house. Clear it gently by hand, then turn the furnace power off for thirty seconds and back on. If it still will not light, call.
Cold house right now? Call (555) 010-0142
Related services
- Furnace RepairGas furnace not lighting, blowing cold, cycling off or locked out with a flashing light.
- Boiler & Hot Water HeatCold radiators, banging pipes, low pressure or a boiler that keeps shutting down.
- Heat Pump RepairIced over outdoor unit, lukewarm air, or backup heat running nonstop.
- Furnace Tune UpA full check and cleaning before the first hard freeze, or midwinter if it is acting up.