Every heating appliance has the same three-part chain: a power supply, a heat source, and a safety device that cuts the heat when something is wrong. When heat disappears but the machine still runs, the safety device has almost always done its job. On a dryer that is a thermal fuse tripped by a blocked vent; on an oven it is a bake element or igniter; on a microwave it is the high-voltage section, which is the one case on this page where the honest answer is to stop and call someone.
Read this first
- A microwave's high-voltage capacitor can hold a lethal charge long after the appliance is unplugged. Do not remove the cabinet, do not 'just look', and do not trust a video that says to discharge it with a screwdriver.
- If you smell gas at any point near a range, dryer or oven: leave the building, do not touch switches, phones or the appliance, and call your gas utility or 911 from outside. Do not troubleshoot a gas smell.
- Lint in a dryer duct is a fire load, not a performance issue. A dryer that has started running hot and slow is telling you the vent needs clearing now.
- Unplug an electric appliance, or pull the double-pole breaker on a hardwired one, before opening any panel.
What it usually means
A tripped safety device is a symptom, not a cause. Fitting a new dryer thermal fuse without clearing the vent that overheated it gets you a few loads before the new fuse blows too. The same logic applies to an oven that keeps failing an element and to a dishwasher that never dries — before you buy the part, work out what asked the part to fail.
Electric appliances add a specific trap: a 240-volt dryer or range on a double-pole breaker can lose one leg and keep running. The drum turns, the lights work, the panel lights up, and there is simply no heat, because heat is the only function that uses both legs. That is a breaker or a supply fault, not an appliance fault, and it is worth ruling out before you order anything.
What to check first
Rule out half-power on 240-volt appliances
If a dryer tumbles or a range's clock and burners work but nothing heats, reset the double-pole breaker firmly off and back on. A dryer that runs on one leg is the classic no-heat call that is not the dryer at all.
Check the dryer vent before anything else
Disconnect the duct at the back and run the dryer for a minute — strong warm airflow at the wall means the machine is fine and the duct is blocked. Restricted venting is what trips thermal fuses and cycling thermostats, and it is also a genuine house-fire risk.
Watch an electric oven element come on
Set the oven to bake and look. A working element glows evenly orange within a couple of minutes. Blisters, a break, or a section that stays dark means replace it. A bake element that never glows while the broil element does points at the control or the element circuit rather than the oven overall.
Listen to a gas oven try to light
A glow-bar igniter that lights orange but never opens the gas valve is the most common gas oven fault — the igniter has weakened and no longer draws enough current to trip the safety valve. It looks like it is working, which is exactly why it fools people.
Test a microwave with a cup of water, then stop
One minute on a measured cup of water: if it is not noticeably hot, the high-voltage section has failed. That is where the checks end. Do not remove the cabinet.
Check the dishwasher is being fed hot water
Run the kitchen tap hot before starting a cycle. A dishwasher that never gets above about 120°F at the inlet will not dry and will not clean properly, and no part inside the machine will fix a cold supply.
DIY, technician, or licensed trade?
This is about who is allowed to do the work, not how hard it is. The bottom row is not a difficulty rating — it is the legal and safety line, and it does not move for confidence or experience.
- Clearing a dryer vent run and replacing flexible foil duct with rigid or semi-rigid metal
- Replacing a dryer thermal fuse or cycling thermostat once the vent is confirmed clear
- Swapping a plug-in oven bake or broil element
- Calibrating an oven's temperature offset from the control panel
- Replacing an oven temperature sensor, a control board, or a dryer heating element with hardwired terminals
- Diagnosing a dishwasher heating element or high-limit thermostat
- Anything requiring a meter reading on a live 240-volt circuit
- Gas oven igniters and safety valves, and any work on gas piping or connectors
- Microwave high-voltage components — magnetron, diode, capacitor and transformer
- Repairing or replacing the branch circuit feeding a 240-volt appliance
Likely parts and what they cost
Our estimates for a typical US job, not quotes. “Part only” is what the component costs bought online against a model number; “installed” adds a technician’s diagnostic and labor.
| Part | Part only | Installed | Notes |
|---|---|---|---|
| Dryer thermal fuse | $5–$20 | $130–$250 | Cheap part, but replacing it without clearing the vent just buys a few loads. |
| Dryer heating element | $30–$90 | $150–$350 | Electric dryers only. Often sold as a kit with the thermostats. |
| Oven bake or broil element | $25–$90 | $150–$400 | Plug-in versions are a genuine DIY job; hardwired ones are not. |
| Gas oven igniter | $40–$110 | $180–$450 | Weakens gradually — a glowing igniter can still be a failed one. |
| Microwave magnetron or HV diode | n/a — licensed labor | $150–$400 | Compare against a new microwave before authorising on an older unit. |
Prices are general estimates for typical US jobs, not quotes. What you actually pay depends on your appliance's brand and age, the part required, your region, and each shop's labour rate. Get the model number off the appliance before ordering — the same part varies in price across models.
Step-by-step guides for this symptom
7 guides cover this fault across 4 appliance types. Each one works through it in diagnostic order, with tools, parts and the point at which it stops being a DIY job.
- 45–120 minutesDryer
Dryer Not Heating — Electric and Gas, Diagnosed in Order
Dryer tumbles but clothes stay wet? Check the cycle setting, a lost 240-volt leg, the vent, thermal fuse, cut-off, element, and the gas ignition sequence step by step.
- 45–120 minutesDryer
Dryer Takes Too Long — Restore Full Drying Speed
A dryer that needs two or three cycles is almost always an airflow problem. Clean the vent, test the lint screen, check the blower and moisture sensor bars.
- 30–75 minutesOven & Range
Oven Not Heating At All — Electric and Gas Diagnosis
Oven completely cold while the cooktop works? Diagnose a dead bake element, weak glow-bar igniter, blown thermal fuse or bad sensor with this DIY guide.
- 45–90 minutes plus preheat timeOven & Range
Oven Not Heating Evenly — Map the Problem Before You Fix It
One side burning, the other raw? Separate hot spots from a miscalibrated oven with the toast test, then check preheat, door seal, elements, convection fan and sensor.
- 30–75 minutesOven & Range
Oven Broiler Not Working — Electric and Gas Diagnosis
Broiler dead while baking works fine? Test the broil element, check the gas broil burner and igniter, and rule out the selector switch and control relay.
- 15–30 minutes for safe checksMicrowave
Microwave Runs But Doesn't Heat — What You Can Safely Check
Microwave lights up and turns but food stays cold? Here is what you can safely check yourself, why the high-voltage side is off limits, and when to just replace it.
- 15–45 minutesDishwasher
Dishwasher Not Drying Dishes — Why, and What Actually Helps
Dishes coming out wet? Rinse aid, water temperature, loading and unloading order matter more than most people think. Plus how to test the heating element.