turbo air model mur-60

[ectofix]

Billy,

That cooler uses a coil-sensing thermostat.  By that, I mean that the thermostat sensing bulb is actually mounted within the evaporator (cooling) coil instead of being suspended out in the air steam (such as in a walk-in) .

 

A coil-sensing thermostat is designed for cut-out temperatures (to turn the compressor OFF) well below freezing – ranging from 21°F to 18°F (depending on your dial setting).  The designed cut-in temperature (to turn the compressor ON) is around 40°F± 3°.

This is a common thermostat configuration for counter-top and prep coolers.  Bear in mind that when temperature within the evaporator coil reaches…say…20°F, the actual air temperature to chill the box would be a much higher – probably around 35°F.

 

Obviously yours isn’t working properly.  Here are several possibilities:

The thermostat is faulty, or… The system’s refrigerant flow is inadequate, either due to a RESTRICTION or a LOW system charge.

 

That latter possibility may not make sense to you, so consider this:

 

If the system is low on charge or if the refrigerant isn’t feeding the evaporator coil as it should, then the coil isn’t getting fed enough refrigerant to supply it in its entirety.  As such, it’s likely that the coil section which envelopes the thermostat bulb is no longer performing in the cooling process.

Yet, the section of evaporator coil that IS getting adequate refrigerant – IS cooling.  Consequently, THAT section is doing all the work, chilling the air to sub-freezing temperatures, freezing your product…with that same frigid air passing back through the relatively dormant section of the evaporator coil…to THEN cool the thermostat bulb.  So at this point, the coil-sensing thermostat has been relegated to only sense the 18° AIR temperature.

 

There are more dynamics of physics at play here, but it gets too complicated and confusing if you’re not familiar with the inner-workings of a refrigeration cycle.

 

Anyway, the low refrigerant flow conditions that I’ve described will result in a thermostat satisfying ONLY at a box temperature WELL below what your desired range is, or in some instances, may not satisfy AT ALL.  So the compressor will just keep running…and running…and your lettuce freezes.

 

Whichever the problem yours may be, you will need to call a technician to troubleshoot and repair it.

[billyli947]

Does turbo air have a tech department that can help me with the unit? If

they don’t  have what type of technician could help me?

[ectofix]

Have your model and serial number handy and then Call Turbo Air.  If it’s less than three years old, it may still be under warranty.  Whether it is or isn’t, they might recommend a company in your area.

 

Their phone number and warranty policy is delineated in the operator’s manual.  Here’s a copy:

 

http://www.turboairinc.com/index.php/lanotattachments/download/file/id/145/store/1/mur_muf.pdf

 

Otherwise, Let your fingers do the walking in the phone book for a refrigeration repair company.

[alnelson]

It’s a turbo air, so if the warranty is up, you probably want to decide whether you want to sink any money into fixing it or not.

[billyli947]

In the meantime, ill have to buy a replacement for the thermostat. On the manual, it says the thermostat model that works with it is turbo air 30283L00. thats all I need to buy before I hire the technician?

[alnelson]

This should be the thermostat you need http://www.partstown.com/turbo_air/trba30283l0100

 

If you put the new thermostat in and it still gets too cold, you know you’ve most likely got a refrigeration problem which will be expensive to fix.

[billyli947]

Alright, thanks for the help. Here’s hoping it’ll fix the issue. If not, What type of unit do you recommend that fits the dimension and style of the MUR-60?

[alnelson]

Most 60″ undercounter refrigerators are similar in size. The only real thing to watch out for is height, there are a few different options as far as the height of the casters.

 

I’ve had good luck with True and Beverage Air, they are both good units and have a good warranty. A True TUC-60 or Beverage Air UCR-60 would both be similar units.

 

Hopefully its just a thermostat and it will be a cheap fix. Good luck.