Best temprature control method for walk in freezer? Thermostat or Pressure switch

Hi Guys,

Forum newbie here, decided to quit lurking the shadows and ask a question.

What is the best temperature control method for a small walk in freezer, thermostat or pressure switches? I have delt with bolth and feel that a digital temperature control should be standard but i keep seeing systems setup with only the pressure switches controling the temp. Maybe someone could set me straight.

Thanks, Jon

So much trouble there with using the L.P. switch for temperature control. Low pressure switches should used for just that purpose only. Ambient temperature variations and expansion valve hunting after startup makes it difficult to accurately set L.P. as a thermostat. I still preferre the Penn A19ABC-41 over the digital control as the storm season here messes with our mains power and in turn fries any electronics. BTW, cyclones are no help either. Apart from that, i'd recommend electronic temp controls.. Mike.

carel digit controller, ir33.... lp switch for safety purposes only..... my opinion anyway

Thanks for your feedback!
I feel that the pressure switch only is sort of old school but I keep getting other service techs coming along behind me removing digital controls and going back to the pressure switches only setup.
Jon

Quote:

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Originally Posted by MrAir

Thanks for your feedback!
I feel that the pressure switch only is sort of old school but I keep getting other service techs coming along behind me removing digital controls and going back to the pressure switches only setup.
Jon

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Strange that they would do this?? More call outs when temperature is not right. Ask them why they choose this method.

Quote:

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Originally Posted by mikeref

Strange that they would do this?? More call outs when temperature is not right. Ask them why they choose this method.

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I do a bit of work for a large national restaurant chain and they call a few different service companies out (All depends on who makes the call) sure makes for a lot of fun when your following behind someone with opposite ideas from yours!
I have no way to know for sure why, but i keep on thinking maybe that’s the way grandpa used to do it so that’s the way they do it.

Really doesn't make sense to have a working thermostat removed from service and just go back to using L.P. control. Guess they have been taught that way and no-one will be able to tell them any different, however you can make a difference just by knowing the logical answer..Mike.

I am sure the perfect system control has not been developed yet, despite all the producers claims. There are demand defrost system controllers incorporated with regular cycles . But I still like to have a LP controller/switch to protect the compressor from flood back if some idiot leaves the freezer door open and coil frosts up, which will ignore the stat demand to run, plus have a liquid sv that cycles with compressor.
I am old alright.

It's indeed old school but I'm sure many younger techs born in the digital age don't have a clue how you can regulate temperature with a pressure switch.
I should prefer thermostat..what happens to temperature if coil is partially frosted up?
To use LP as a temperature control, you must have also a relative stable HP which is not always the case.