How to winterize a parking air conditioner — end-of-season storage checklist

• Table of Contents

1. Step 1 — dry the evaporator and condensate path
2. Step 2 — clean condenser and evaporator coils
3. Step 3 — isolate or maintenance-charge the battery bank
4. Step 4 — seal the housing and document service due dates

Truck and RV owners who park for the winter or shift to heater-only operation need a proper end-of-season shutdown to protect the parking AC over months of cold idle. Skipping winterization invites moisture damage to the evaporator, mould in the cabin duct, battery degradation and corrosion of contactors. This checklist covers the four critical steps: dry the system, clean the coils, isolate the battery and seal the housing.

Step 1 — dry the evaporator and condensate path

Run the AC in fan-only mode for 30 minutes on the last warm day to dry residual condensate inside the evaporator coil. Clear the condensate drain line with compressed air and check the drip tray for standing water. Trapped moisture freezing inside the coil can crack copper tubing or split the drain pan.

Step 2 — clean condenser and evaporator coils

Rinse the rooftop condenser coil with low-pressure water and a coil-safe cleaner. Vacuum and wipe the cabin-side evaporator. Replace the evaporator pre-filter. Dust and salt left on the coils over winter cause pitting corrosion that destroys cooling capacity within 1–2 seasons.

Step 3 — isolate or maintenance-charge the battery bank

If the truck or RV will sit unused over winter, isolate the house battery bank with the main disconnect or fit a battery maintainer. LiFePO4 banks self-discharge slowly but should be stored at 40–60% state of charge in a heated space if possible. AGM/lead-acid banks need a maintainer to avoid sulphation.

Step 4 — seal the housing and document service due dates

Fit the supplied winter cover or apply a UV-resistant tarpaulin over the rooftop housing. Note the next service date (compressor refrigerant check, evaporator pre-filter replacement) in your fleet log. Vethy recommends a full pre-season recommissioning in March/April before the first cooling demand.

Frequently asked questions

Can I leave my parking AC powered all winter?

Yes if the truck or RV is stored in a heated environment. For unheated storage at sub-zero temperatures, isolate the battery bank to prevent slow drain and freeze damage to the control board.

Do I need to remove the parking AC for winter?

No. Rooftop parking AC is designed for year-round outdoor exposure. A winter cover protects against UV and salt-spray but the unit itself does not need removal.

What temperature can a Vethy parking AC survive in storage?

Vethy units survive non-operating storage from -40°C to +70°C ambient. Operating range is -10°C to +50°C ambient.