Rebuilding Process

 

This is a general overview of the process by which we build our cooling units.  If  this is the first time you have ever had trouble with an ammonia cooling system, you may find this page interesting.  We will show you the parts that typically go wrong with an ammonia cooling unit and what is unique about the way we repair them.

 

"A"  The first photo is showing the evaporator section of a Dometic cooling unit that has gone bad.  Usually you would not be able to see this portion of the coil because it is embedded in urethane foam inside the refrigerator box. We have stripped away some of the foam to show the rust that has formed, causing the unit to leak ammonia which is usually evident by a strong ammonia odor inside the box.

 

"B"  The next photo shows part of an evaporator that has been patched at some time by another re-builder.  You can see the sleeve that was welded on to cover up an area that was too rusted to repair.  While this will fix the leak in this particular spot, you can imagine that if this area has rusted through, then other places in this evaporator are soon to follow. Which is why at RVCOOL, we came up with a process of replacing the entire evaporator section rather than trying to patch.

 

"C" This photo simply shows a Dometic cooling unit that we have cut the evaporator section from, getting it ready for the new tubing.

 

"D"  Our first step is bending all the pipe that will make up the replacement evaporator.  We designed all our evaporators (both Norcold and Dometic) as one piece units with the hydrogen return tube inside the larger 7/8" pipe.  You can see it coming out the top of the larger pipe in the photo. Then we bend the small lines that carry the liquid ammonia from the condenser to the top of the evaporator. Then the brackets are cut, which will pull the evaporator tight against the refrigerator fins.

 

"E"  This next photo shows the pieces for a Dometic RM2600 replacement evaporator that have been laid out in a heavy steel welding fixture to be assembled. A unique feature of the Dometic RM2600 and RM2800 series cooling unit is the freezer bars that protrude inside the freezer compartment.  In this photo you can see the freezer bars have been attached to the evaporator tubing.

 

"F"  This is a picture of a complete welded and assembled evaporator ready to be installed in an RM2600 series cooling unit.  The great thing here is all the tubing is brand new, leaving little chance for a leak to just pop up.

 

"G"  Next the complete evaporator section is screwed down in a Line-Up frame the same dimensions as an actual refrigerator box and the cooling unit is secured in place on top of it.  The line-up frame insures that each cooling unit will fit the same in any refrigerator box.

 

"H"  This is a picture of a Norcold cooling unit that has just had a new evaporator welded in. Now it is ready to be flushed out for contaminants and sent to the charging room.  One reason we flush the cooling unit is for contaminants that can get in the tubing during the various stages of assembly, but another and very important reason is to check the flow of certain lines to make sure there are no restrictions.  Very often we will find a cooling unit that has had a line welded shut or just partially welded shut at the factory.  Sometimes this will stop the cooling all together but more often it just makes the cooling unit act sluggish.

 

"I"  After the units are charged and ran for several hours they are sent to the paint and foam shop. Here the entire cooling unit is primed and several coats of enamel paint are added to give the cooling unit a new look.

 

"J"  Once the paint has had time to completely cure it is ready to have the urethane foam insulation pack replaced.  We do this by placing the cooling unit in a fiberglass mold that was cast from and actual refrigerator box.  We use a fiberglass mold to install the insulation rather that than a refrigerator box for two reasons. First, we ship a lot of cooling units and don't always have the box there. Second, the reinforced fiberglass mold can withstand a lot more pressure than the refrigerator boxes, especially the newer models with the thinner vacuum pack insulated walls.

 

"K"   In this photo the new foam pack has been installed.  During the foaming process, a sheet metal back is installed on the back of the cooling unit.  Once the cooling unit is installed in the refrigerator the sheet metal back will be sealed to the back of the refrigerator box to prevent moist air from being pulled into the refrigerator.

 

"L"  Finally the finished product.  A completely re-manufactured cooling unit ready to ship. We have a product that we can be proud of, and one the customer knows will last.