Parts under review / Mechanical Capillary Thermostat
Mechanical Capillary Thermostat
- A
- Capillary length, body to the tip of the bulb
- B
- Bulb length — measure bulb diameter too
- C
- Panel cutout, not the bezel
Excess capillary can be coiled, so err long. The temperature range is printed on the dial face — photograph it.
Reference illustration, not to scale and not a product photograph. We will add actual sample photos and measurements after verification. Need the figures now? Ask on WhatsApp.
Reference photo
Mechanical temperature controller with capillary probe, for ovens without a digital display.
Useful first checks. If your oven has a digital temperature display, this is not your part — see the PID controller instead.
What this part is
A mechanical temperature controller. A gas-filled bulb on the end of a fine capillary tube sits in the chamber; as it heats, the gas expands and trips a snap-action contact. No electronics, no display — the temperature is set by a dial.
How it fails
The capillary tube gets kinked or crushed during a previous repair and loses its charge, at which point the contact either never closes or never opens. A thermostat that has lost its charge usually fails to the off state, so the symptom is an oven that will not heat at all despite good elements.
What decides whether a replacement fits
These are category-level selection factors, not specifications for a specific product. Confirm each value from the machine and the physical part.
| Parameter | Typical | Why it matters |
|---|---|---|
| Temperature range | Commonly 50–300 °C or 0–300 °C for deck ovens | Printed on the dial face. A range that stops short of your bake temperature is useless; one that runs far beyond it costs you dial resolution where you actually work. |
| Capillary length | Measured from the body to the tip of the bulb | Too short will not reach the sensing position. Excess can be coiled, so err long. |
| Bulb diameter and length | Must pass through the existing sensing pocket | A bulb that will not enter the pocket cannot sense chamber temperature. |
| Panel cutout and shaft | Standard cutouts with a D-shaft or flatted shaft for the knob | Decides whether it mounts in the existing hole and whether your knob fits. |
| Contact rating | Rated in amps at 250V | Must exceed the load it switches. Many installations switch a contactor coil rather than the elements — check which before sizing. |
The mistake people actually make. Measuring the bezel rather than the panel cutout, and discovering on site that the hole is wrong.
Product specifications to verify
| Capillary length | Not verified |
|---|---|
| Temperature range | Not verified |
| Panel cutout | Not verified |
| Shaft diameter | Not verified |
Electrical details to verify
| Voltage | Not verified |
|---|---|
| Contact rating | Not verified |
Fits these models
We have not published a verified model list for this part yet. We only list a machine once we have measured the part against it or a customer has confirmed the install — a list padded with guesses is worth less than no list.
Send us your nameplate and a photo of the old part and we will review what the evidence supports.
What to photograph and measure
Photograph the dial face, body markings, terminals and sensing bulb. Measure the capillary and bulb, and record the voltage and contact rating from the part label.
Help us understand your requirement
Product-specific fit, availability and sales information are being verified. Share your equipment and part details to support the research.
Brand and model names are used for identification only. Product-specific compatibility requires supporting evidence.
This page is a category guide. Product-specific specifications remain unpublished until checked against a physical sample.
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