Thor Ace Macerator vs Gravity Dump: Complete RV Waste System Setup Guide

The Quick Answer

On your 2013 Thor Ace 29.2, you'll need to close the manual dump valve on the passenger side (typically a 3-inch gate valve or bayonet valve) to shut off the hose connection, then activate the macerator system on the driver's side using the control panel switch inside your RV. The macerator will then pump the waste through its own dedicated discharge hose. Most Thor Ace models from this era have a clearly marked valve handle on the passenger side that you simply turn clockwise to close, effectively isolating that dump point so waste flows to the macerator instead.

What's Causing This

Your Thor Ace 29.2 has a dual waste discharge system designed for flexibility - a traditional gravity dump on the passenger side and a macerator pump system on the driver's side. The confusion happens because both systems connect to your black and gray tanks, but they need to operate independently. When you want to use the macerator, the traditional dump valve must be completely closed to create proper pressure and flow direction.

The macerator system works by using an electric pump to grind waste and pump it through a smaller diameter hose, allowing you to discharge further away from your RV and even uphill if needed. However, if the passenger side valve remains open, the macerator won't build proper pressure and waste will just flow out the gravity dump instead of through the macerator system.

Tools You'll Need

• No special tools required for valve operation
• Flashlight or headlamp for better visibility under the RV
• Disposable gloves for handling connections
• Water hose for cleanup afterward
• Your RV owner's manual (for macerator control panel location)

Step-by-Step Fix

Closing the Passenger Side Dump Valve:

1. Locate the dump valves on the passenger side of your RV - these are typically mounted in a compartment or under a protective cover
2. Identify the main waste valve (usually the larger 3-inch valve) - it may be a gate valve with a handle or a bayonet-style valve with a quarter-turn cap
3. If it's a gate valve, turn the handle clockwise until it stops - this closes the valve completely
4. If it's a bayonet valve, ensure the cap is fully seated and twisted to the closed position
5. Make sure any sewer hose is disconnected from this side before proceeding

Operating the Macerator System:

1. Connect your macerator discharge hose to the outlet on the driver's side (usually a smaller diameter connection than the gravity dump)
2. Run the hose to your desired discharge location - the macerator can typically pump 75-100 feet horizontally and uphill up to 6-8 feet
3. Inside your RV, locate the macerator control panel (often near the tank level monitors)
4. Turn on the macerator pump switch - you should hear the pump motor running (never run the pump when tanks are empty as this can damage the pump)
5. Open your black tank valve first using the tank control panel
6. Allow the tank to empty completely, then run the pump for an additional 5-10 seconds to clear the lines before closing the black tank valve
7. Repeat with gray tank if desired
8. Turn off the macerator pump and disconnect the hose

When to Call a Pro

Contact an RV service technician if you can't locate the passenger side dump valve or if it appears stuck and won't close with reasonable force - forcing it could damage the valve mechanism. Also call a pro if the macerator pump doesn't activate when you flip the switch, makes unusual grinding noises, or doesn't seem to be moving waste effectively even with the gravity valve closed.

If you discover any leaks around valve connections or if the macerator discharge hose fitting is damaged or missing, these issues require immediate professional attention to prevent costly contamination problems. Additionally, if your tank level sensors aren't working properly, have them serviced before relying on the macerator system, as you need accurate tank readings to avoid overfilling or running the pump dry.