Suburban Nautilus Series Water Heater Vent Caps

3 products

The vent cap is the exterior trim you see on the outside of the sidewall where a Suburban tankless heater exhausts. It carries combustion gases clear of the wall and keeps rain, road spray and insects out of the exhaust path, which is why a cracked or missing one tends to show up as hard starting rather than as a cosmetic problem.

These come in 1 inch, 2 inch and 3 inch versions at the same price, so the only decision is size. Measure what you have before ordering rather than guessing from the heater model, since the figure refers to the cap itself and not the tank or the heater’s output.

If you are replacing one, plan to reseal the flange. Old sealant rarely comes off cleanly and the new cap needs a fresh bed to keep water out.

What does the Suburban Nautilus Series vent cap do?

The Nautilus vent cap covers the exterior exhaust opening on Suburban Nautilus tankless water heaters. It directs combustion gases away from the sidewall of your RV and keeps debris, insects, and weather out of the burner chamber. A cracked or missing cap can let moisture into the heat exchanger and trigger ignition faults, so replacing a damaged one is a small fix that prevents larger repair work.

How do I know which Nautilus vent cap fits my water heater?

Check the model and serial label on the inside of your water heater door. Suburban Nautilus units are tankless on-demand models, and the vent cap part number is tied to the specific Nautilus generation installed in your RV. Confirm your model number before ordering. If you also need a replacement door or access panel, see our Suburban tankless water heater doors collection.

Can I install a replacement Nautilus vent cap myself?

Yes. Most Nautilus vent caps mount with a handful of exterior screws over a sealed flange. Remove the old cap, scrape the old sealant, run a fresh bead of butyl or self-leveling lap sealant around the opening, and screw the new cap into place. Plan on 20 to 30 minutes and a clean, dry day. For related Suburban water heater controls, see our Suburban D and DE on/off switches collection.

When should I replace my RV water heater vent cap?

Replace the vent cap if you see cracks, UV chalking, missing louvers, or signs of pest intrusion at the exhaust. Owners doing a seasonal inspection often catch this during winterizing or de-winterizing; see our RV winterizing kits collection for related supplies. A compromised cap lets rain reach the burner assembly and can cause hard starts, soot buildup, or fault codes on the control board.