Johnson control thermostats--Awsome

I just received 2 johnsons from Dennis Thomas today and they are great little thermos...Their probes a very small in diameter and the unit itself is small compaired t the ranco giants..lol..Thanks,
-Matt

Don't these come with a digital readout that can be mounted something like 800 ft. away? That will be very handy for me this winter.

They can handle a max 1500 watts, correct?

Chris,

Now that you asked, I see that I had a mistake on my website. The 800ft number I gleaned off of another website when I had been researching these. The actual manufacturer's recommended distance using 16 AWG wire is 500 ft. I apologize for this mistake, I should have checked my facts a bit better.

Now, keep in mind that yes, you can mount the unit 500 ft away but this would create a couple of problems. (There is no seperate, stand alone digital display only. It is all one single unit.) The most obvious is running the power supply from the unit to the heat source. Obviously, you would need 500 ft of that cable. The second being at 500 ft the resistance created would cause a discrepency between the actual temperature at the probe and the displayed temperature. The manufacturer also recommends using a twisted pair, shielded wire for any lengths over 50ft due to electrical interference that may be encountered at those distances.

Technically, the unit itself can handle 1875 watts but this of course is limited to the rating of the power supply cord and the supply cord to the heat source. I advise 1500 watts so no one pushes the unit to the max and possibly starts a fire due to over loading those supply cords.

Any other questions, I am happy to answer.

That makes sense.

What are the basic advantages of this thermostat over the Ranco? Can they handle heating a cooling duties?

Dennis would be better to answer but my opinion that are smaller than the ranco and from what I get from the directions they can we used as heat/cool. There is also a lot of extras you can get...Like mounting hardware and things like that

Originally posted by Chris_Harper2
That makes sense.

What are the basic advantages of this thermostat over the Ranco? Can they handle heating a cooling duties?

There are a couple of basic advantages.

1. It is quite a bit smaller than the Ranco.
2. The temp probe is not soldered on but attached to a screw terminal. This makes it a snap to replace defective probes or lengthen the lead.
3. It has built in LED light to indicate when the unit is heating/cooling.
4. It can be programmed to shut off if the temp probe fails. The temp probe stops sensing, the unit shuts off. No cooked animals.

For mounting it has the standard screw holes like the Ranco. In addition, it can also be mounted to standard DIN rail.

The unit can be operated in either heating or cooling mode. All that is needed is to open the unit and move a jumper.

Hey Dennis do they come programmed to shut off if the probe fails or is that somehting I have to do..I have found that they are easy as heck to program....

I send them all out pre-programmed to shut off and a temp differential of 1f. All you would need to do is set the set point temperature.

Great, I havent gotten past the setpoint and the diff on the menu yet..lol..BTW Ill be getting some more here shortly and feel free to throw one of those boas in the box...Thanks man,
-Matt

I tell you what, I'll send you two of my boas for that Het anery you got. I need that little girl for my Ghost project.