Help - Reefer Won’t Quite Reach Set Point

My reefer has always done the same thing at a setpoint of 34* continuous. It won't do it on lower settings somewhere around 20* or lower. I thought it was a problem until I talked to a thermoking mechanic and he explained how it was just modulation and the unit is working like it's supposed to with the temp varying from the setpoint like that. Another way you can tell it's just modulation is to set it on cycle 34* and watch to see if it does what it's supposed to - pull down to 34* and shut off - if it does then it's fine.

 

This place is amazing! So many people happy to jump in and help.
Thanks kids! ( Flatbedder doing medical leave here so I read all the threads)


















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A couple of things you could try although at 36 ° f you should be ok for chilled produce, my question is if its not able to go down to 34 °f how were you able to get to - 10 °F? Was it during the summer heat in Phoenix? That hot sun on the reefer will make the difference, specially if the trailer is not that well insulated how old is the reefer? What is unusual about this is most reefers are good for chilled down to about 32 °F its when you've got to go down to -10 °F that the issues start as most reefers are only built for chilled and therefor don't have the insulation for frozen, the transport company dispatchers when they allocate a load to you, mostly are unaware of this very fact hence why they may assign you a frozen load. Personally I would not worry to much if its sitting at 36 °f as it still keeping the load chilled, what is more important is what temp was the product at when it came out of the warehouse? A reefer will not bring the product temp down to what ever level the shipper require, all it will do is maintain the temp it was loaded at. Sure it may cool the boxes the product is in, but if you were to stick a thermometer in the actual product it will still be at what ever it was loaded at or a bit higher this is fine provided it does not get to high when you reach the delivery point ( receiver) each company will have what they call "acceptable temps" for each type of product, for e.g meat can be a lot higher then say cheese, milk or yogurt. So meat would be fine at about 45 °f.

If your trying to get the temps down try unhooking the trailer, if this works problem solved hook it back up and see it maintains the new temp, another option I'd try is check the grill on the fridge motor sometimes if you get a high pressure water hose and shoot some water through that if there's a build up of dirt in there can help fix things too, my thought is if is summer time this is whats making the trailer not cool to well specially if its an older trailer that is not that well insulated. Although if its still getting down to 36 ° that's still pretty good. Its only if it was not cooling at all that I'd be really concerned. Failing that if your still concerned then its best to call out a fridge mechanic.