Here I've got an OEM evaporator coil that has not been installed yet using a constant cut in style control, so remember the operation of the constant cutting control, no matter how cold I turn this and it gives you numbers from 1 to 7. So if I turn it to 7, 7 being represents the temperature of how cold the evaporator coil gets before it turns off the compressor, but no matter what you set this number at. It always turns back on at 40 degrees. That in itself is self defrosting, because, no matter how cold I set the cut out temperature, which is when the compressor cuts out or turns off the cut in temperature or when the compressor turns back on, will always be at 40 degrees.

They do this because this is an electromechanical control. It uses the gas charge in the sensing bulb. That's set up to always turn that control back on when this coil temperature inside, where this sensing bulb, is located notice. The sensing over here.

Ok, it's embedded in that coil when that sensing bulb gets back up to 40 degrees, coil temperature. It's going to turn that control back on, so that in itself is self defrosting, because 40 degrees, coil temperature, is above 32 degrees. 32 degrees is obviously when we form ice so constant, cutting control example. Here's another example of an evaporator coil that also uses a constant cut in temperature controller.

You notice the style of the evaporator is different. This is a MOLLE unmounted, coil or moly on style mounts. You know, basically, in between two doors on the doorframe. The temperature controller is right there.

So here's a look at the inside same thing. This is a constant cut in control, maintains a 40 degree coil temperature. Just a little bit different arrangement than the last coil, but still does the same thing, no matter how tall how cold we turn the dial, it always cuts back in at 40 degrees. Here's an up close of a constant cutting temperature controller.

This is a bad one that I pulled out and I happen to save it, but sensing bulb embeds in your coil. The numbers just with the inside single pole, single, throw this right here, is an example of an electronic constant cut in control. This one has some options, though this one is programmable by the manufacturer. This is made by Danfoss, but it can be programmed to do all kinds of stuff, so you've got two probes: one gets embedded in the evaporator coil one senses the air temperature.

So again, there's no specific function that these things absolutely do. It's all based off of the programming when they get brought from the factory at what they have, but some of your options are constant cutting always turning on at 40 degrees, and on top of that it can actually have a normal timed defrost function, built into it Too for extra defrost, but it can also be temperature terminated. So if you've got a coil temperature and an air temperature, they can look at the coil temperature and they can also look at the air temperature to get a more accurate, defrost termination temperature to make sure your box isn't getting above 40. This particular control eye.

You see the terminal designations there, there's C for compressor, l and l is line. H, is your heater circuit and is your neutral circuit and F? Is your fan circuit? So this is actually for refrigerator. So this one doesn't use the heater circuit, but it does use the fan circuit, so they've actually got an algorithm built into this control to stage the evaporator fan motors and turn them off based off of their funky algorithm, but they do it to save energy. So this is typically an aftermarket control.

I have seen them from some OEMs but they're typically aftermarket. This is a very versatile controller. This particular one does not have built-in defrost, but they actually, the manufacturer, pin, which is made by Johnson Controls, has actually come out recently with a new control. I can't remember the designation or part number, but it's the same look right here, but it actually has built-in defrost also, but you can do all kinds of stuff with this.

This would be. I would consider an aftermarket electronic digital controller. This can be used for soup wells to keep them hot. You can use this as a heating or cooling control, because we have a normally open and a normally closed contact, so we can close when it gets to a certain temperature or we can open when it gets to a certain temperature.

You if you've got some ingenuity and you you can actually use this control as a constant cut in temperature control or two, because it's digital you can set it to turn on and off at any temperature. So if you know the temperature that the inside of your evaporator coil is going to be at a certain box temperature, you could theoretically set you can embed this into the coil and set that to adjust that this guy here is one of the more commonly seen Johnson, we call them a pen temperature controller. This one is a control that also can do heating or cooling, because it has a normally open and normally closed contact. The range is pretty broad on this.

One right here can go from a hundred degrees down to negative 30 degrees. The interesting thing about this one is: it has a coiled sensing bulb on the top. That is not remote. So when you're using this particular control, you have to be cautious about where you put it depending on the application you're using it for so, if I'm using this in a walk-in cooler, I would not want this to be mounted usually on the front of the coil, Where the air blows out, because you wouldn't want it to get hit by that air temperature, you could do it, but you just have to pay attention wherever you mount it.

You have to know what your temperatures are actually going to get to. This is typically mounted in the return Airstream up on the back wall of a walk-in cooler, evaporator coil. This guy have to say is the number one most common temperature controller that we use for walk-in, freezers and coolers. It is a Johnson or a pin.

Temperature controller made by Johnson this particular model does have a normally open and normally closed contact. I shouldn't say this particular model. This one is just the single pole single throw model, but you can get it in a single pole. Double throw this one right here again very versatile: the sensing bulbs a little bit bigger, but you theoretically could embed this in evaporator coil and use this as a constant cut in control.

I wouldn't suggest it because you'd have to bend the fins pretty big to be able to shove this into those, but I've seen it done, but anyways. This is a very broad range. Control goes from 100 degrees down to negative 30. Very, very common truck stock item.

Usually keep one or two of these if you're doing a lot of walk in.