wax thermostat

 What is a wax thermostat? 

What does it look like? 

How does it work?

And how do I wire one in if I want to?

A wax thermostat (also called an "oil" thermostat) is really nothing more than a bimetallic disk, with a hole in the center. They always have a small rod protruding from the disk, that extends well beyond the side of the disk. This rod is coated with wax, or filled with it; this keeps the device from sticking together or moving too freely during assembly.

They are used as temperature limiters and controllers in furnaces and heaters, and are usually fast acting devices; they will switch on or off within about 50 milliseconds if based on a 90-degree rise across their active elements (the space between the nut and washer). They can also switch at less drastic temperatures if used as switching elements; just make sure you don't exceed their design limits. All of my heaters use them for switching -- not for controlling the temperature.

As controllers, they are quite dependable when properly installed. However they do take some practice to install properly; they must be assembled exactly right to work well in most applications. If you want something to learn on, then I would suggest buying one at your local electrical supply house (they usually carry them) and figuring out how it actually works before you start wiring up anything. Practice by assembling one correctly, then pulling it apart and reassembling it wrong so you understand how each part relates to the whole operation. Then put it back together correctly! After you learn this procedure this will be your best guarantee of success in installing them!

A wax thermostat is simply a bimetalic disk with two wires attached to opposite sides of its center-hole. The rod that sticks through its center has a ferrule attached at each end for attaching wires, using special locking nuts (see below). A special nut holds both these nuts down into holes drilled through the side of the disk so both wires can be easily attached without disassembling any part of it . . . unless you have more complex wiring requirements than are shown here. For simple applications you might want to just glue their wires directly into holes drilled through the side of their disks -- making sure all connections remain insulated from each other at all times! Another method involves bending their wires into loops before attaching them directly into these holes as shown here -- allowing them to flex outward when hot without shorting anything out! However there are always a few cases where soldering or gluing is necessary: see below where I show how I tinned my wires after bending them over slightly: GLUING THE WIRES FOR SOLDERING This shows what activated soldering looks like after assembly: The amount of solder would vary depending on design but this should give you some idea of what solder looks like when melted onto copper wire! Here's another more complex example showing how several individual parts relate together When installing any thermostats keep these things in mind: Always coat all joints with suitable amounts of insulating paste first! Make absolutely certain that no joint conducts any current both inside your control box as well as between your control box and your heating wire(s)! There must be no conductive paths available for any current used by your system -- use insulating paste between adjacent surfaces for best results! Glue all parts properly together before connecting any wires . . . then test AFTER ALL CONNECTIONS ARE MADE TO THE SYSTEM! Make certain that power can NOT reach your heating system under ANY conditions except those required by user-installed sensing switches such as manual pushbuttons connected properly between live power lines and ground via safety switches or fuses as required by applicable codes & local laws!!! Never connect power directly between two parts that move relative to each other either inside or outside such conductive housings!!! To do so will usually create short circuits inside such metal structures that may exist within some components - thus creating unsafe conditions capable of causing fires!!! If possible make all connections inside fiberglass or plastic housings designed specifically for continuous use while hot -- preferably enclosing ALL electrical parts inside weatherproof metal boxes BEFORE applying power!!! NONE OF MY DEVICES HAVE ANY OIL INSIDE THEM NOR DO THEY REQUIRE OIL TO OPERATE SUCCESSFULLY DESPITE WHAT SOME ELECTRICIANS MAY TELL YOU!! This includes oil filled bulbs containing electric heating elements which may require oil filled tubes passing through external covers made from aluminum alloy material - thus creating dangerous electrical connections subjecting users to fire hazards due to failure rates associated with aluminum alloy constructions especially when subjected to continuous high voltage risks.. Instead I now use fiberglass reinforced plastic housings containing high voltage lamps enclosed within totally sealed high voltage lamp pulsing circuits which are totally self contained & DOT approved - allowing me free use within other types such as paint ball guns & nail guns since no hazardous fluids pass through these units during normal operation! No oil needs ever be added since this eliminates ALL potential problems associated with oil being spilled onto hot surfaces during operation thereby creating potentially dangerous electrical hazards whenever power is applied!! Do NOT attempt ANYTHING shown on this page unless you fully understand what you're doing - doing