Reefer has difficulty to reach -10 temp

Was the reefer on during loading? Was it hot?

 

Ya, not so unusual. If when loaded the load was warmer than the set temp, it may take a day or two to pull it down. Like they always say, a reefer is not meant to pull down the load's temp, mainly it will maintain the load's temp when it was loaded. When I haul frozen food (rarely) say like -10, and the outside temp is high 90's to 100+, my reefer unit might rise like to low 0 to 5 degrees during daytime, and go down again as night temps go down. Ice cream reefers are extra insulated just for that purpose. Btw I have a TK sb190 unit, newer eng. but '03 trailer.

 

Could be any number of things...dirty condensor, low freon, leaky compressor...

If you load fresh picked watermelons in Geogia in August on a hot sunny day, and set the temp to 57, even a brand new unit with everything working top notch won't reach the setpoint for probably two days or more.

We used to lease some 387 Peterbilts with dual stacks. The pipes were short enough and not turned, so that they shot exhaust right back at the unit. The leasing company refused to turn or modify the stacks so we turned the trucks back in.

 

For a unit to pull an MT box to 4 degrees in the middle of summer ain't bad. Utility trailers do not normally have real thick insulation, or at least mine did not.If TK checked it out, I would load the wagon and go.

 

Tell him to look in the guages section to see what the high side and low side pressure is and then call TK and tell them the situation . Then ask if those pressures are in line where they should be ..

I have never had a problem at -10 , now I have had issues when its set at say -20 for icecream...

 

Also, it is much harder to pull an empty box down to -10 than it is a loaded one, especially in the summer and humidity makes it worse. Even on a cool fall day it can take close to an hour to get to minus 10. An empty box in 100 degree heat I n the hot sun you are pretty much wishing on a star.

 

Older equipment with a few issues, this sounds typical and within "norm". If the chute is dumping too much air near the front of the trailer this will exacerbate cooling issues in the summer but it doesn't sound like this is an issues if you can get it down to -4 empty and door closed.

We have some new thermo-kings and these things are awesome. With the door open to a hot warehouse (to cool the floor loaders at Sterelite who asked for the favor) and outside temp near 100 F, I set the unit to 55 and it easily ran internal temp down to 55 and held it there. Closed up, they can run down to -10 really quick at 95 degrees outside and empty. These new units seem to have an impressive temperature in/out differential capacity

 

As reefers age, their insulation loses its value

http://www.thermoking.com/news-article.aspx?id=245

 

1st, you cant run the unit with the doors open, then the curtain must be in good shape to work corectly.