Cummins/Onan — Piggyback Evaporator Installation

Installation

From a Cummins/Onan service manual covering: ES2075s, FS1870s, M11979s, M1976s, M1977s, M1978s. Check it applies to your exact model before use.

Applies to: Kubota 2482B engine

Procedure

1. Remove the mattress, mattress support and other items that interfere with the installation.
2. Place the template on the sleeper floor next to the evaporator and mark the drain tube and mounting holes.
3. Locate refrigerant lines a minimum of 7 inches (177.8 mm) from the piggyback evaporator expansion valve.
4. Drill a 5/8-inch drain tube hole and two 5/16-inch evaporator mounting holes in the sleeper floor.
5. Drill a 2-inch diameter hole in the sleeper floor for the refrigerant line grommet and install the grommet.
6. Remove the two top cover mounting screws from the evaporator end of the existing evaporator/heater assembly.
7. Bergstrom unit: install the baffle as shown and reinstall the cover.
8. Kenworth unit: disable the built-in control and valve before disconnecting OEM wiring.
9. Install the piggyback evaporator and secure it to the evaporator/heater assembly and compartment floor.
10. Seal the mating surfaces with silicon or other suitable duct sealant.
11. Install a 7/16-inch I.D. vinyl drain hose on the drain tube if moisture could drip on components.

Source: Cummins/Onan service manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.

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