115 volt Cooler Control & Thermostat Retrofit Kit For Mastercool Plus or Contractors Series

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4.00 LBS
  • 115 volt Cooler Control & Thermostat Retrofit Kit For Mastercool Plus or Contractors Series
  • 115 volt Cooler Control & Thermostat Retrofit Kit For Mastercool Plus or Contractors Series
  • 115 volt Cooler Control & Thermostat Retrofit Kit For Mastercool Plus or Contractors Series


For 115 volt application.

This kit can be used to replace the interior control box and thermostat combination on the Mastercool Plus or Mastercool Contractor's Series Cooler, some of which are now obsolete, including #P225101A, P225102A, P218301A, P218601A.
This kit consists of a new control box to be mounted on the outside of the cooler, a new plug receptacle box with wire leads for the inside of the cooler, a new 115 volt motor cord, and a new digital thermostat for inside the house. Requires rewiring of new plug receptacle box to new control box. Disconnect all power before attempting. Read all directions. Level of difficulty:medium.

You can read the control box and thermostat owner's/installation manual here.

Wiring schematic for 115 volt

To maintain use of purge pump feature with standard pump, we recommend purchasing also an additional pump receptacle to tie in to the new control box.
115 volt pump receptacle.

New cooler control is Dial part #7624. Features include:
Digital Evaporative Cooler Control with Thermostat
2 Speed 1/3 to 1 HP 115V/230V
Automatic start and stop for temperature comfort.
Automatically pad pre-wet.
Automatically adjusts from High to Low speed
Digital display with separate controller in water proof box.
Optional 2 / 4 / 8 hour timer.
Optional dump feature. (Use an extra standard cooler pump for timed water purge, like a Clean Machine.)
Motor rated 1HP @ 115V, 2HP @ 230V
Pump rated 2A @ 115VAC and 1A @ 230VAC
UL listed.

Replaces P225101A, RK301A

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18 Reviews

  • 5
    This product was exactly what I needed to retrofit my twenty year old Mastercool. It included all parts needed for easy installation. Thermostat was simple to program. A great product from Dial.

    Posted by Lawrence Geusz on Jul 30th 2023

    Quick service and delivery as well from knowledgeable people .

  • 4
    Compact replacement and upgrade, easy to install

    Posted by Dave on Jul 21st 2023

    Provision for mounting a drain plug-in connection would be helpful.

  • 4
    Likes & Dislikes

    Posted by Dial 115 Volt Retrofit Cooler Control Kit on Jul 12th 2023

    The controller on my Master Cool CMC431A cooler recently failed & found that replacement parts are obsolete. I like that Dial makes a retrofit kit that works & allows continued use of the unit. That being said, there are improvements that could be made. The power recepticle box doesn't have a provision for the drain pump plug. I had to modify the box to accommodate the plug. The control unit is designed to be mounted on the outside of the cooler. We live in a mountain area with dry arid summers but cold snowy winters, requiring the unit to be covered. A box mounted on the outside of the unit is not practical. I wound up mounting the power receptical box near the front of the unit where the original control unit had been. I then had to splice all of the wiring & run it to the rear of the unit where I mounted the control box. Even if I would have mounted the control unit outside as shown in the instructions, I would still have had to splice in the wiring as what is provided wouldn't reach from the socket box to the control unit. Lastly, I don't like the fact that the thermostat does not have a button that allows manual draining of the unit like the original did. I have sent the original unit to a repair facility for refurbishing & plan to reinstall it upon its return.

  • 5
    Control Retrofit Kit

    Posted by David on Sep 7th 2022

    My 20? year old Mastercool control board was getting erratic. This kit was just the ticket to restore full function and get set for another 20 years. It operates just as described and was straightforward to install. I used a 3/4" box extender to mount the enclosure to the outside of the cooler and pass the wiring to the interior plus one spacer and sheet metal screw thru tab for stability. Very pleased so far.

  • 5
    Cooler control and thermostate

    Posted by C on Jul 31st 2022

    Perfect, just what I needed to get our evap cooler up and working again. There was a mix up in shipping and wrong item was originally shipped but a phone call solved it quickly and painlessly. Received the item shortly after the phone call. Easy to install. Highly recommend Indoor Comfort Supply.

  • 5

    Posted by Cameron Troop on May 30th 2022

    Exactly what I needed and with online instructions that were great

  • 2
    115 volt cooler control & T-stat

    Posted by Adrian Jewell on Jul 20th 2021

    Worked fine for two days, then would not start cooler, showed a E03 error, which is jumper wire, wired incorrectly. Jumper wire is wired for 115 volt, now have to run control through diagnostic test, then hope it will start cooler without E03 error.

  • 5
    Life Saver

    Posted by Josue Caban on Jul 13th 2021

    On eBay the original part can range from $259-689. Your price was so reasonable. There is an orange wire hanging and the manual did not explain what it was for. That is my only suggestion for correction. It works fine without it. Thanks for the retrofit solution.

  • 4
    Fixed my aging MasterCool unit

    Posted by JB on May 29th 2021

    Easy to install and allowed me to fix my aging AdobeAir cooler that the electronics went bad on. Otherwise, the cooler is still in decent shape so this saved me from having to replace the whole cooler.

  • 4
    New controller

    Posted by Neal R on Jun 19th 2020

    I just mounted it directly to the new cooler since it’s exterior now. My plugs didn’t have an extra drain outlet either but I only need that once a year. Thermostat is a little sensitive with it going between low and high a lot sometimes. Other than that works great. New thermostat is way nicer than old one.

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