China Custom Limit Disc Thermostat Control Switches Therm o-Disc

Snap Disc, or 3/4″ Limit switch thermostats are bimetal mechanical thermostats that function via the thermal expansion and contraction of a bimetal disc that “snaps” from a convex to a concave shape at a set temperature. carrying up to AC 110V/400V, 10A-60A amps-240 Volts.

L150-20 Heater Limit Thermostat Thermodisc Open On Rise

KSD302 SHL120 Heating Limit Thermostat Thermodisc with Flange Plate Adapter

KSD302R-453 Normally Open/Manual Reset 3/4″ Snap Disc Limit Control Switches

Limit Disc Thermostat Control switches are the same for different stoves, Electric ovens, electric water heaters, 電加熱器, household appliances, 電機, refrigeration or heating equipment. so to replace it cheap you just have to understand their function.

Why are they called Snap Discs Limit Thermostat is because they are round like a disc and have a Bi-Metal Strip that Snaps when heated to a certain temperature!

Most Limit Disc switches are SPST Thermostat single pole single throw. This means one wire in and one wire out. So when the temp rises the wires are connected which means the switch is closed ( Equipment power outage ).

It will also keep the fans running after the Electric oven / electric heater has been manually or automatically turned off until the exhaust temperature cools down. Unless it is like the Disc Thermostat which has another identical switch just like it to keep the fans running. Sometimes they have a part number with a designation F for Fan or L for Low Limit but don’t be fooled they are the same type of switch! After all you can test it with a continuity checker or ohm meter. When the switch is cold the meter should read open or infinity on the ohms scale and when heated above 140 Degrees F the switch will close and read a short or no ohms Usually a bad low limit switch means the Electric oven, electric heater stops running after the 15-20 min Electric oven, electric heater start-up cycle.

Also the part numbers for each Electric oven, electric heater manufacturer may differ.
Since most open when the exhaust temp drops below 140 degrees f the part number may be called L140 Also they close when the exhaust temp rises above 140 degrees f or 150 degrees f so they may be called F130 or F160 Let’s get real here folks these Limit Disc switches are not fully digital with precise accuracy!! So 130 或 160 may be within the specs of the bi-metal strip inside meaning there are the same switch!!

So in the pic here below is one that I found cheap. Note the physical mounting is usually the same with the mounting holes 2 inches apart. Most Electric oven, electric heater have a male quick disconnect terminal but some Electric oven, electric heater like YAXUN who make their own switch have screw terminals. However the screws can be removed and a clip can go on it but they do charge more for the extra unnecessary hardware!!

Application: Applicable to electrical equipment and household appliances with large power loads such as welding machines, 熱水器, heaters, electric vehicle batteries, 洗衣機, 雪櫃, sanitary ware thermostats, 等.

1. 電氣參數: 1) CQC質素控制, VDE, UL認證, CUL系列. AC250V 50~60Hz 5A / 10一個 / 15A~60A (電阻負載).
2. UL交流125V 50Hz 15A (電阻負載).
2. 工作溫度範圍: 0~240℃ (自選).
3. 恢復和操作溫差: 8~100°C (自選).
4. 接線方法: 插頭端子 250# (彎曲0~90°可選); 插頭端子 187# (彎曲0~90°可選, 厚度 0.5, 0.8mm可選).
5. 電氣強度: 交流50Hz 1800V持續1分鐘, 無閃爍, 冇故障.
6. 聯繫表格: 常閉型: 溫度升高, contact disconnects, 溫度下降, contact connects; 常開型: 溫度升高, contact connects, 溫度下降, contact disconnects.
7. 外殼保護級別: IP00防護等級.
8. 接地方式: 透過恒溫器嘅金屬外殼連接到設備嘅接地金屬部件.
9. 安裝方法: KSD302 series with movable ring, fixed ring, mounting plate movable ring, ordinary stainless steel cover with mounting holes.
10. 工作溫度範圍: -32℃∽+320℃.