A rooftop swap on a 14 x 14 in opening is a two-person, two-hour job with hand tools. The weight is the only hard part. Read the manufacturer's installation sheet that ships in the box; this page is the overview so you know what you are getting into before you order.
Before the roof
- Confirm the opening is 14 x 14 in and the roof around it is sound. Soft roof means stop and repair first.
- Confirm ducted or non-ducted and that the kit's ceiling assembly matches.
- Shut off shore power and the generator, and pull the AC breaker. Disconnect the 12 V battery if the system has a wall thermostat.
- Have a second person, a ladder each, and a way to get 80 to 100 lb onto the roof: two people on a ladder, a roof-rated ladder with a helper above, or an engine hoist with a strap.
Tools
Socket set with a 1/2 in and 7/16 in, screwdriver set, torque wrench or inch-pound driver, wire strippers, utility knife, putty knife, caulk gun, shop vacuum, voltage tester. The kit includes the new roof gasket; the mounting bolts come with the ceiling assembly.
Remove the old unit
- Inside: drop the ceiling grille or ADB, disconnect the 115 V wiring at the junction box (photograph it first), unplug the control cable, remove the four mounting bolts. The old unit is now loose.
- Roof: lift the old unit straight up and off. The old gasket usually stays stuck to the roof; scrape it off and clean the opening area to bare roof membrane.
- Vacuum the opening and the ceiling cavity.
Set the new unit
- Peel and stick the new gasket to the base of the unit, not the roof, so it lands square.
- Lift the unit onto the roof and set it over the opening, drain channel toward the rear of the RV. Center it by eye from inside.
- Inside: hang the ceiling assembly mounting frame, start all four bolts, then tighten evenly in a cross pattern until the gasket compresses to roughly half its thickness. Coleman specifies about 40 to 50 in-lb. Overtightening crushes the gasket and cracks the base pan; undertightening leaks. If a thick roof leaves the bolts short, Coleman sells 9 in long bolts (8333-3211).
Wire it
- 115 V: connect the supply (black, white, green) to the ceiling assembly junction box per the diagram in the box.
- Control: plug the unit's control cable into the ceiling assembly. On a wall thermostat system, land the thermostat wires on the control box (built into a ChillGrille, or the separate package on a plenum-only assembly) and set the thermostat on the wall.
- Heat strip, if fitted: install in the ceiling assembly before the grille goes up.
Finish and test
- Fit the ceiling grille or plenum. On a ducted install, set the dampers.
- Restore 12 V, restore the breaker. Run cooling for 15 minutes. Check for cold air at the grille, the condensate dripping off the roof behind the unit, and no vibration at the shroud.
- Roof: check that the shroud screws are tight and that no sealant is needed. The gasket is the seal; do not caulk the base of the unit.
Time and difficulty
Like-for-like, non-ducted: 1.5 hours. Ducted with a new ChillGrille and thermostat: 2 to 2.5 hours. Brand switch (Dometic or Furrion to Coleman): add 30 minutes for the ceiling assembly change. The job is easier than a water heater and harder than a fan. If you would rather not go on the roof, any RV service shop will install a unit you bring in, typically 1 to 2 hours of labor.
Every Kate RV complete kit includes the new gasket, and the ceiling assembly in it brings its mounting bolts. Install parts are also sold on their own.