Inside Your Oven: Key Parts and Their Functions

Something is wrong with your oven. Maybe it runs too hot, won’t heat at all, or the door isn’t sealing properly. Before you call a technician or start guessing, it helps to know what’s inside and which part is likely causing the problem. At Steve’s Appliance Spares, we’ve helped over 150,000 kiwis find the right part. Knowing which part has failed is half the repair.

This guide walks you through the seven main parts inside your oven, what each one does, how to spot when it's failing, and where to find a replacement. Every part linked here is one Steve's Appliance Spares stocks and dispatches nationwide from our Palmerston North warehouse. Browse the full oven parts range for your model.

1. Oven shelves and racks

Oven shelves (also called racks) are the platforms your trays, dishes and tins sit on. Simple part, but they affect cooking results more than people realise. The right shelf in the right slot is half of even cooking.

Types you'll find

Wire racks. The standard option in most ovens. Good airflow around food. Browse wire racks like the Westinghouse Oven Main Side Wire Rack 0327001322.

Telescoping racks. Slide out fully for safe access without reaching into a hot oven. The Electrolux Rack Side Oven Right Hand 0327001206 is one example.

• Flat baking racks. Solid, smooth surface, ideal for cookies, scones, and other baked goods that need an even base.

Placement and use

• Adjust shelf positions for what you're cooking. Lower shelves for things that need direct heat from the bottom element, middle for most general baking, upper for browning under the grill.

• Clean shelves regularly. Remove them, soak in warm soapy water, and scrub off stubborn residue. Spills baked onto the rack reduce airflow and can transfer flavours.

• Replace if damaged. A bent, broken or seriously rusted rack is unsafe and won't hold dishes properly.

2. Oven lamps

An oven lamp lets you check on food without opening the door and losing heat. A simple part with a big impact on cooking results, because every time you open the door, the oven loses around 25 to 50 degrees.

Types

Most ovens use small incandescent or halogen bulbs designed to withstand high temperatures. Standard kitchen bulbs won't work, they'll crack or burn out fast.

When they fail

Oven bulbs burn out eventually, like any bulb. If the light has gone, replacement is usually a simple swap.

How to replace

1. Make sure the oven is cool and disconnected from power.

2. Locate the lamp cover inside the oven, usually a small glass dome.

3. Unscrew or twist off the cover (oven manuals show this for your model).

4. Unscrew the old bulb and fit the replacement of the same type and wattage.

5. Refit the cover, restore power, and test.

3. Knobs and controls

Oven knobs are your interface with the appliance. They set temperature, choose cooking modes, and run timers. Knobs see daily use, and they wear.

Signs of wear

• The knob spins freely without changing the setting

• The marker no longer lines up with the temperature scale

• The knob feels sticky, stiff, or won't return to off

• It's cracked, chipped, or has come off its spindle

Replacement

Sometimes a good clean fixes a sticky knob. If it's worn out, replacement is usually a pull-off, push-on job. Match the new knob to your oven's brand and model. Some knobs sit on a D-shaped spindle, some on a round one, some clip in. Browse replacement knobs for your model.

4. Electrical components

Ovens run on complex electrical systems. Most DIY repairs in this area are not a good idea, and many are not legal in NZ for an unlicensed person. Knowing what’s in there still helps you describe a fault to a technician.

Control board

The oven's brain. Manages temperatures, cooking modes and timers. If the display is dead, the oven won't turn on, or it ignores the controls, the control board may have failed. This is a technician's job.

Wiring

Wires carry power to elements, lamps, fans and sensors. Burnt or damaged wires are a safety hazard. If you smell burning, see scorch marks, or the oven trips your circuit breaker, stop using it and call a professional.

Fuses and breakers

Ovens draw a fair amount of power. If yours won't turn on at all, check the circuit breaker first, sometimes it's just tripped. If it trips again as soon as you reset it, there's an underlying fault that needs a technician.

5. The inner door

The inner oven door seals heat inside the cavity and usually has a glass window so you can see your food. Two parts wear out here: the glass and the seal.

Glass

Oven door glass is heat-resistant, but it can still crack from impact (a heavy roasting tin slamming against it), or from a sudden temperature change (splashing cold water on a hot oven). Cracked glass needs replacing, both for safety and because the broken seal lets heat escape and changes how everything cooks.

Seal (door gasket)

The oven door seal around the door keeps heat inside. When it goes hard, splits or comes loose, heat escapes around the door. The oven runs longer, uses more power, and the temperature inside the cavity isn't even.

Hinges

The door also relies on hinges to open and close properly. Worn hinges let the door sag or stop it closing flush, which kills the seal even when the gasket itself is fine.

6. Heating elements

The heating elements are the heat source. Fisher & Paykel ovens are among the most common we see in NZ kitchens, and their elements follow this same layout. Gas ovens use a burner instead. When the oven won't heat, the element is usually where to look first.

Types

• Bake element. Sits at the bottom of the cavity. Provides the main heat for baking.

• Grill element. Sits at the top. Used for grilling and browning.

Electric element failure

Signs of failure: the oven won't heat at all, or won't reach the temperature you set. Sometimes you can see the damage, a visible break, blister, or bright glowing spot on the element. Sometimes the failure is hidden inside the element. Either way, replacement is the fix.

Gas burner issues

Clogged burner holes or igniter problems can prevent proper flames. Gas work should always be done by a qualified gas technician under NZ rules.

7.Oven thermostat 

 

The thermostat is the part that tells the control board how hot the oven is, so it knows when to cut power to the elements. A faulty thermostat means the oven misreports its own temperature. Food burns, undercooks, or the oven simply won't reach the temperature on the dial.

Signs of failure

• The oven runs too hot or too cold compared to what you set

• Food burns even on low settings, or undercooks on high

• The oven never seems to reach temperature

• The oven cycles on and off too often, or not enough

Diagnosing a thermostat fault usually means using an oven thermometer to compare actual temperature against the setting. If they’re consistently far apart, the thermostat needs replacing, and this is typically a technician job. This is one of the most common calls we get from customers across NZ. If you’re not sure, email steve@appliancespares.nz with your model number and we’ll point you to the right part.

Troubleshooting common oven problems

Uneven baking

Check three things in order:

1. Temperature accuracy. Use an oven thermometer to compare actual temperature against the dial. If they're far apart, the thermostat may need calibration or replacement.

2. Shelf placement. Make sure the dish is centred for even airflow, not pushed against one side.

3. Hot spots. Most ovens have one. Rotate your dish halfway through the bake to even things out.

Oven won't reach temperature

Check for element failure in electric ovens or burner ignition issues in gas models. If the elements look fine and the oven still won't heat, suspect the thermostat, a fault here can stop the elements turning on at all.

Food burning or undercooking

Check temperature accuracy with an oven thermometer first. Then check baking times, every oven is slightly different, and times that worked on your last oven may need adjusting for this one.

Oven won't turn on at all

Start with the circuit breaker, sometimes that's all it is. If the breaker is fine and the oven still won't turn on, suspect the control board, internal fuse, or wiring. Call a technician.

DIY repair or call a professional?

Some oven parts are within reach for a confident home user. Others need a licensed technician under NZ rules. Here's a clear guide:

Fitting oven parts safely

 Important: Only fit these parts yourself if you have experience installing this kind of part. If you do not have that experience, hire a professional to do it.

Oven shelves, knobs and lamp bulbs are user-replaceable, no special skills required beyond turning the oven off and letting it cool.

Anything electrical, including heating elements, thermostats, control boards and wiring, and anything to do with gas, must be done by a qualified, licensed technician under New Zealand rules. This is a legal point as well as a safety one. If you're not sure which kind of repair yours is, email Steve's Appliance Spares before you start.

Habits that extend your oven's life

• Wipe spills quickly. Spilled liquid baked onto the cavity surface gets harder to clean every time the oven runs.

• Deep-clean regularly. Follow your oven's manual, some have self-cleaning cycles. Avoid harsh oven cleaners on self-cleaning surfaces, they can damage the coating.

• Don't overload. Overcrowded ovens cook unevenly, because hot air can't move around the food.

• Use a baking stone for bread or pizza. Stones help regulate temperature and produce a more even base.

• Avoid foil on the bottom. Foil on the oven floor interferes with heat distribution and can damage the lower element or cavity.

• Check the door seal regularly. A simple test, put a piece of paper between the door and the seal, close the door, then try to pull the paper out. If it slides out easily, the seal isn't sealing.

Where to buy oven parts in NZ

Steve's Appliance Spares stocks oven parts NZ-wide for all the major brands. Dispatched from our Palmerston North warehouse with New Zealand Post and New Zealand Couriers. Trusted by over 800 service companies, electrical wholesalers, suppliers and servicemen.

Browse by part type:

• Oven Elements, for bake, grill and fan oven elements

• Oven Thermostats, for thermostats and temperature controls

• Oven Knobs, for replacement control knobs

• Oven Door Seals, for oven door seals and gaskets

• All Oven Parts, to browse the full oven parts range

Frequently asked questions

Why is my oven not heating up?

The most common cause is a failed heating element. Electric ovens have a bake element and a grill element, and either can fail independently. Sometimes you can see the break or blister on the element itself. Other times the fault is a thermostat, which stops sending signal to power the element. For both, replacement should be done by a qualified, licensed technician.

How do I know if my oven thermostat is broken?

Use an oven thermometer to compare actual oven temperature against the dial setting. Let the oven preheat for 15-20 minutes, then check the thermometer reading. If the actual temperature is consistently far off the dial, by more than around 20 degrees in either direction, the thermostat is likely faulty. Replacement is a technician job.

Can I replace my oven door seal myself?

Often, yes. Most oven door seals push or clip into a channel around the door frame and can be swapped by hand once you've removed the old one. The job is straightforward as long as you can match the right seal to your oven. Browse oven door seals, and if you're unsure of the right fit, email us your model number.

Why is my oven cooking unevenly?

Three usual causes. First, the actual temperature may not match the dial setting (use an oven thermometer to check). Second, the dish may not be centred on the shelf, leaving uneven airflow around it. Third, your oven may have natural hot spots, very common in older non-fan-forced models. Rotating the dish halfway through the bake usually evens things out.

Should I replace my oven elements myself?

Under New Zealand rules, electrical work on an oven, including replacing heating elements, should be done by a qualified, licensed technician. Elements carry mains voltage and connect into the oven's wiring. It's a safety and legal point, not just a difficulty rating. We supply replacement elements, and your technician can fit them.

How do I find my oven's model number?

Look around the door frame, the underside of the cooktop, or inside the oven door (sometimes on a label that's only visible when the door is open). Write the full model code down, including any letter or number suffix. The model number is the single most important piece of information for ordering the right part.

Need help finding the right oven part?

Not sure which part you need, or which oven model you've got? Email steve@appliancespares.nz with your model number and a description of the fault, and Steve's Appliance Spares will point you to the right oven part before you order. Shipped nationwide from our NZ warehouse.

About Steve's Appliance Spares

Steve's Appliance Spares is a New Zealand owned and operated parts supplier based at 731C&D Tremaine Ave, Palmerston North, 4414. Operated by an appliance industry expert, the business supplies spare parts nationwide to the NZ public and to over 800 service companies, electrical wholesalers, suppliers and servicemen. The range covers ovens, cooking appliances, washing machines, fridges, dishwashers, vacuum cleaners, coffee machines, microwaves and more, dispatched with New Zealand Post and New Zealand Couriers for the fastest affordable options available.