Advent RV Air Conditioner Not Cooling? Complete KoolRV Adapter Fix Guide

What's Going On

WARNING: Air conditioning modifications involve electrical components and refrigeration systems. Improper modifications can result in electrical shock, fire, refrigerant leaks, or equipment damage. Consider consulting with a qualified HVAC technician before attempting modifications. These modifications will void your warranty.

Yes, you can absolutely restrict airflow too much and damage your Advent air conditioner or cause it to freeze up. When you reduce airflow over the evaporator coil, the coil temperature drops dramatically, which can lead to ice formation that blocks airflow entirely and potentially damages the compressor. Your plan to adapt the KoolRV adapter to your Advent unit is sound in theory, but you'll need to be careful not to over-restrict the airflow. The corner discharge design you mentioned is indeed problematic - it creates turbulence and reduces the effective air distribution compared to center-discharge units like your old Coleman.

Regarding your second question about removing the dividing wall, this is necessary because most aftermarket adapters like the KoolRV system need to create a more direct path from the return air intake to the supply ducts. The factory dividing wall often creates additional restrictions and turbulence that work against the adapter's design. However, since no commercial adapter exists for your Advent unit, you'll be pioneering this modification.

Why This Happens

Your cooling problems stem from several factors related to the Advent's design compromises. The corner discharge placement creates airflow pattern disruption that works against efficient air distribution. Instead of smooth laminar flow into your ducts, you're getting turbulent air that doesn't carry the cooling capacity effectively through your fifth wheel. This is why opening those slide vents helps - you're bypassing some of the restrictive ducting and allowing more direct air circulation.

The airflow restriction issue is governed by basic HVAC principles. RV air conditioners are designed to move a specific volume of air (determine required CFM from your unit's manual or contact Advent customer service for airflow specifications) over the evaporator coil. When you reduce this airflow below manufacturer specifications, several problems occur: the evaporator coil temperature drops below freezing, ice forms and blocks airflow further, and the compressor has to work harder because the system can't absorb heat effectively at the evaporator. This creates a cascading failure that can burn out your compressor.

The dividing wall removal requirement exists because these walls are typically designed for the factory airflow pattern. When you install an aftermarket adapter, you're fundamentally changing how air moves through the unit. The dividing wall that made sense for the original design now becomes an obstruction that creates pressure drops and turbulence in your modified system.

Getting Ready

Before attempting this modification, you'll need to measure your Advent's airflow characteristics. Purchase a digital anemometer (around $30-50) to measure air velocity at various points in your duct system. Take baseline measurements with your current setup, then monitor airflow as you make modifications. You'll also need basic tools: screwdrivers, tin snips, duct tape, and possibly sheet metal for fabricating adapter pieces.

Study your KoolRV adapter carefully to understand its design principles. Most of these systems work by creating a more direct path from the return air to the supply plenum while eliminating some of the factory restrictions. Take photos of your Advent's internal layout before making any changes - you'll want documentation if you need to reverse the modification or troubleshoot problems later.

Consider the warranty implications as well. Your Advent unit likely has at least a year of warranty remaining, and modifications like this will void that coverage. However, given your dissatisfaction with the unit's performance, this may be an acceptable trade-off. Make sure you have a backup cooling plan if your modification attempts fail during peak summer heat.

Walking Through the Fix

WARNING: Turn off power to the air conditioner at the breaker panel before beginning any modifications. Verify power is off with a multimeter before touching any electrical components.

Start by removing the interior ceiling assembly and exposing the Advent's discharge plenum. With the KoolRV adapter in hand, identify how you can modify it or create mounting brackets to work with the Advent's corner discharge design. You may need to fabricate transition pieces from sheet metal to redirect the airflow from the corner discharge to a more central distribution pattern that matches your existing ductwork.

When removing the dividing wall, wear safety gloves to protect against sharp metal edges, do this gradually and test airflow at each step. Use your anemometer to monitor air velocity and calculate CFM by multiplying velocity by the cross-sectional area of the airflow path - you want to maintain manufacturer-specified CFM through the evaporator section. If airflow drops below this threshold, you've gone too far and need to add some restriction back. Consider installing an adjustable damper system that allows you to fine-tune the airflow balance between cooling performance and ice prevention.

Test your modifications during moderate weather first, not during peak heat conditions. Run the unit and monitor for ice formation on the evaporator coil every 30 minutes for the first few hours of operation. Check the evaporator coil through the return air grille while maintaining safe distance from moving parts. If ice is present, shut down immediately and allow complete defrost before restarting. If you see any frost or ice buildup, immediately increase airflow by opening restrictions or adding ventilation. The goal is finding the sweet spot where you get maximum cooling performance without risking freeze-up.

Document your final configuration with photos and measurements. Note the optimal damper positions and airflow readings for future reference. You may need to make seasonal adjustments - what works in 85-degree weather might need tweaking when temperatures hit 100+ degrees in the Everglades summer heat.

Beyond DIY Territory

If your modification attempts don't yield satisfactory results, consider having a custom adapter professionally fabricated. A local HVAC sheet metal shop could create a purpose-built adapter for your Advent unit based on the KoolRV design principles but tailored to the corner discharge configuration. This would likely cost $200-400 but could provide better results than trying to adapt an incompatible system.

Another professional option is upgrading to a ducted air conditioning system designed specifically for RVs with challenging cooling requirements. Companies like Cruise Air and Coleman make systems with multiple air handlers that could provide better cooling distribution than any single-unit solution. While expensive ($1500-3000 installed), this might be more cost-effective than repeatedly modifying units that weren't designed for your specific application.

Finally, consider consulting with an RV service center that specializes in cooling system modifications. They may have experience with similar Advent unit modifications or know of aftermarket solutions that aren't widely advertised. Sometimes the best solutions come from technicians who've solved similar problems for other frustrated RV owners in hot climates like the Everglades. Given the complexity of these modifications and the potential for equipment damage, professional consultation is often the most cost-effective approach, especially when warranty coverage is still in effect.