Uni-Stat IIIa Cooling or Heating Control

  • Item #P90
  • Price: $59.99
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In stock, will ship on Saturday, March 25

The Uni-Stat IIIa Heating or Cooling Control does not require programming, and is the only control that features an adjustable duty cycle, for increased accuracy and energy savings. It is also the only control we sell that can handle up to 15 amps when used for heating - other models typically have a 10 amp limit for heating.

No programming - To set the temperature, just hold the stainless toggle switch until the desired temperature displays and release. To change from cooling to heating mode, flip the slide switch on the side of the case. To change the duty cycle (which controls whether the control powers your heating or cooling unit fully or in a 50% on, 50% off mode), flip another switch on the side of the case.  All setting are retained in the event of power outage.

   Why a selectable duty cycle? Many refrigerators, freezers, and electric heaters will overshoot the desired temperature if they are running on full power right up until shut off. If they are running 50% of the time (in the 50% duty cycle mode), they gradually approach the desired temperature in 10 minute on and off cycles and then turn off without overshooting the setting, saving energy and increasing accuracy.  

Feature List:

  1. This controller provides flexibility; such as wall mounting, choice of °F or °C, adjustable differential and more.
  2. Wall-mounted installation provides excellent user visibility selection.
  3. Convenient switch-selectable COOL or HEAT operating mode. No programming required.
  4. Unique energy saving switch-selectable 50% duty cycle for excellent temperature stability, without unwanted “overshoot” cooling or heating operation. The 50% cycle is 10 minutes ON, then 10 minutes OFF in COOL mode (5 minutes ON, then 5 minutes OFF  in HEAT mode), then repeat, until the desired temperature is achieved and your unit shuts off.  This feature will automatically switch to 100% duty cycle if the 50% choice is not providing sufficient temperature set-point achievement.
  5. Flashing Alarm feature “AL-“ alerts user if sensor temperature is more than 5°F above (COOL mode) or below (HEAT mode) set-point.
  6. Flashing alarm feature “Er-“ will indicate a sensor fault, such as ‘open’ or ‘shorted’, and will automatically shut off system until repair is effected. This is easily accomplished with simple plug-in sensor replacement, or possibly on-site repair of the sensor cable.
  7. Sensor cable length of 8’ enables flexible system set-up for operation monitoring and control.
  8. Sensor fits a standard 1/4″ thermowell.
  9. Microprocessor accuracy provides +/- 1°F control throughout full range of 10° –  220°F (-12° – 104°C).
  10. Simple set-point check or adjustment with one finger toggle, after which all system settings will be briefly displayed for confirmation to the user.
  11. Automatic compressor protection is provided in the COOL mode, to prevent possible short-cycling damage.
  12. Operating differential (bandwidth) may be adjusted up to +/- 3°F (up to 6° bandwidth). Factory setting is +/- 1°F.
  13. Load capacity at 120 VAC is up to 15 Amps (1600W for heating).
  14. Designed and assembled in the USA.
  15. 3 Year Warranty

Average rating 10 out of 10 ( based on 3 reviews )

Uni-Stat III

Review by Gary on 1/17/2023

As all products, parts that I have purchased from Williams, this product is outstanding.

Sweet and Simple

Review by Craig on 11/29/2016

Virtually non-existent foot print and no need to go through multiple menus just to make a basic temperature adjustment. Easy to see and adjust in my dimly lit bar without the need for a flashlight. Much less hassle than my fancy dual stage LCD temperature controller. Another great way to simplify brewing!

It's about time.

Review by Andy on 8/5/2016

This is a great temperature control. It's about time that some one came up with a control that's easy to use. To be able to switch between heat and cool with out taking it apart to change jumpers is a God sent. No insane programing to make it work! I love it. I a brewer not a programmer!!!

Oct 09, 2020 by Bob

Q: Will it work like the kegland one as a distillation controller?

A: No, it will not shut off at a preset temperature, and the probe is too wide to fit into a still head.

Jul 12, 2018 by Gil

Q: Will this temperature probe fit inside the Weldless Pot Thermowell (P79)?

A: Yes

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