Three photos follow. The first shows a truck we had built but then rejected for a number of vendor-related reasons (that I will not go into in this thread). It shows a Thermo King UTS reefer on the driver's side.
I asked why the reefer was not placed on the passenger side, but do not recall the answer. It never became an issue because we did not buy the truck. However, the Thermo King vendor, who was among the most knowledgable reefer vendors I have met, clearly saw no harm in mounting the reefer on the driver's side.
Physically, there is no reason you cannot mount an underbody reefer on the driver's side. On the next truck, Diane and I took a more hands-on approach and specified that the reefer would be on the passenger side. We did so, not for any specific reason, except that several drivers said it is safer from harm there.
Both when moving and parked, more vehicles pass the truck on the left than the right. The reasoning is the right side of the truck is less likely to be hit by another vehicle. Generators are less expensive to replace than reefers. Thus, the generator goes on the passenger side.
The second photo shows our current truck with the reefer mounted on the passenger side. It is somewhat unusual to mount a reefer under the sleeper. We did so to enable a shorter wheelbase on the truck.
The third photo shows me giving a reefer tour (no jokes please) to a number of plant managers and engineers at the Carrier facility in Athens, GA. In December, 2006, Diane and I visited with these folks about the Carrier 850 mounted under body. They were pleased to see one in the flesh.
As others have said, Carrier does not make a reefer designed to mount on the frame or under the truck body of a straight truck. The underbody mounts, known as split installations, that are commonly seen on expedeiting trucks are dealer modifications, done at the dealer level.
I urged the Carrier people several times and in every way I knew how to design a true underbody product. They did not budge, citing engineering costs and market considerations. As a result of experiences Carrier people had with our reefer, a minor factory change has been made to the reefer to make underbody units easier to service in the field but it is of little consequence in a new purchase decison.
(By the way, after working out one bug and replacing one factory-defect item, both under warranty, our reefer has run like a top for nearly a year now and provided reliable service.)
(Also by the way, it is a myth that Carrier does not support underbody installations. To work out the bug, Carrier flew two engineers and a pile of equipment from their Athens, GA office to our dealer in Memphis. They debugged the reefer in one day.)
Regarding reefer split installations, the biggest variable on the reefer's success or failure is the dealer that installs it. Some dealers have it figured out. Others do installations that are a disaster from the moment the reefer is turned on. Still others do it wrong but not in a way that shows up until the reefer has been run a few times.
Our Carrier reefer dealer of choice is Crow's Truck Service in Memphis, TN. Three times it has happened that while we were there, underbody reefer trucks were there for major repairs. These were trucks where the split installation had been poorly done and the installing dealer could not fix it. I know one driver who says, "Nobody touches my reefer but Crow's." Diane and I are close to that same opinion but practical considerations drive us to other dealers on occasion.
If we were having a new split system reefer installed, Crow's would be the one.
Top mounteed reefers have their advantages as DaveKC pointed out. One disadvantage is the expense of hitting a bridge or low-hanging tree limb is greater if the reefer is up top.
We went with an underbody mount to gain space in the sleeper. That decision may force us to replace our reefer ahead of its time because of corrosion, but it is a decision we would happily make. The sleeper space is just too nice to have to give it up to a reefer. The reefer does not care if it is comfortable or not. We do.
