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tkman55, Mechanic
Category: Medium and Heavy Trucks
Satisfied Customers: 139
Experience:  Diesel Truck Mechanic for over 34 years. Specialize in Thermo King and Carrier Transicold refrigerated units
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How can I fix the code 21 on a termo king

Customer Question

how can I fix the code 21 on a termo king
Submitted: 2 years ago.
Category: Medium and Heavy Trucks
Expert:  tkman55 replied 2 years ago.
Are you still in need of assistance
Here is my check list for Cooling cycle check unit needs to be in cool preferably hi speed open the doors and check the ball in the site glass in the reciver tank located against the firewall behind and above the battery it should be floating near the top of the site glass. if it is not floating then you may be low on Freon and have a leak somewhere
next check the sensors by either selecting sensor from the menue on an SR2 or pressing the select button and reading the screen what is the DA discharge sensor the TD tempature differential and the Coil numbers read? TD should be a negative number between -8 and -15 the coil and the DA should be within 4 degrees of each other
so if the ball is floating and the TD is -10F and the coil/DA sensors are close then the refer is full of Freon and is cooling properly so the refer may not be your problem a warm load heat loss thru the trailer doors and walls the set point to low are just a few
let me know
Expert:  tkman55 replied 2 years ago.
checking up on you did you get your problem solved
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