How often do you defrost?

Bs ....

After loaded and doors closed do ppw b4 start rolling
Start the defrost

 

Had sticker on thermo king models saying 45deg and under manual defrost every six hours but I'd do it after break and never had any problems. Some will say when it's very humid and hot do it more often but look up reefer model manual on "the online" and see what it suggests.

 

Ours are set to defrost every 6 hours, regardless (in continuo), or when it senses it may be freezing over. But I will sometimes initiate a defrost an hour or so after closing doors under certain conditions.

 

Our trailers do it automatically while running

 

Never. I let it do its own thing. It only goes into defrost if it's set to below 32. Then again I have my reefer mechanic take apart and clean the evaporator I think it is a few times a year. Anything in there will clog it and freeze it up much faster.

 

I used to do multiple stops all day in hot humid weather...I would get a code for out of range return air on the Thermo-King...well duh..I had the doors open!

I started to hit the manual defrost after each drop and it solved that problem.

 

Seems to me if you don't wait a while [after opening doors] for the new moisture to freeze on the coil, the immediate defrost is a waste of time. It probably takes 15-20 minutes to cycle most of the moist air through the system.

The systems today are pretty smart and can sense when they have excess ice accumulated and will defrost when the time is right.