Skip to content
Mendocino, California. Delivery all over Northern California. Call or text (909) 259-7837

Free RV manual

How to Run an RV Air Conditioner

How much power it needs, why it freezes up, how to clean the filters and what to try before you call for help.

What it needs

A roof air conditioner runs on 120 volt power. It needs shore power, the generator, or a large battery and inverter. It will not run on the batteries alone in most rigs.

Most units start with a hard kick of power. On a 30 amp site, run only one air conditioner and hold off on the microwave or a hair dryer while it runs. A soft start kit can help a small generator start it.

Getting the most from it

  1. Start it early in the day, before the rig heats up. It is much harder to cool a hot rig than to keep a cool one cool.
  2. Close the blinds on the sunny side and use the awning for shade.
  3. Keep the filters clean. Pull them out every couple of weeks in the season and rinse them in the sink.
  4. Wait a few minutes before you turn it back on after you turn it off. It needs time to settle or it may trip the breaker.

If it freezes up

Ice on the coils is common on humid days or cool nights with the fan on low. You will see less air or feel water drip. Turn the cooling off and run the fan on high until the ice melts. Then clean the filters and use a warmer setting.

If it will not start

  1. Check the thermostat is set to cool and set below the room temperature.
  2. Check the breaker in the panel and the breaker on the park post.
  3. Check the voltage. Low voltage at a busy park can stop the compressor. A surge protector with a screen will show it.
  4. Most thermostats need the 12 volt battery to work. A dead battery can stop the air conditioner even on shore power.

When to call a shop

Call a shop if it hums but will not start, trips the breaker every time, blows warm air with clean filters, or leaks water inside the rig.

The maker's own manuals

These guides cover how most RVs work. Your own rig may differ, so check the manual for your make and model.

Renting from us? Call or text 909-259-RVDR before you try a fix. We would rather talk you through it than have you guess, and it is free.

The other manuals

ManualFresh water and the water heaterCity water, the fresh tank, the pump and the water heater. How to fill it, turn it on and keep it clean.5 partsManualBlack and gray tanksThe order, the hose, the valves and what to put down the toilet. Dumping your tanks the right way, step by step.4 partsManualShore power and batteries30 amp and 50 amp shore power, the 12 volt battery side and the inverter. What runs on what, and how not to trip a breaker.4 partsManualPropane, furnace and fridgeOpening the tanks, lighting the stove, running the furnace and fridge, and what to do if you smell gas.5 partsManualSlide outsWhen to open them, when not to, and what to check first. Slide outs are the most common repair on a rental, and most of it is avoidable.4 partsManualAwningsPower and manual awnings, how to set them, and why wind is the thing that breaks them.4 partsManualWinterizing and spring start upDrain it, bypass the water heater and fill the lines with RV antifreeze. Then how to undo it all in spring.4 partsManualGeneratorsStarting it, loading it, keeping it healthy, and staying safe from exhaust.4 partsManualHitching a trailerCoupler, safety chains, breakaway cable and lights. A simple routine to hitch up the same way every time.4 partsManualThe water heaterGas, electric or both. How to fill it, light it, drain it and care for the anode rod, plus what to do when there is no hot water.4 partsManualThe refrigeratorGas and electric absorption fridges, 12 volt compressor fridges, how long they take to cool and how to keep food cold on the road.4 partsManualThe furnaceA propane furnace with a 12 volt fan. How it starts, why it drains the battery and what to check when it blows cold air.4 partsManualLeveling and jacksBlocks, tongue jacks, stabilizers and auto leveling. How to get level, why it matters and why stabilizers are not for lifting.4 partsManualTires, wheels and bearingsTire age, pressure and load, lug nut torque and when to service trailer wheel bearings. The parts that cause the most trouble on the road.4 partsManualTrailer brakes and breakawayElectric brakes, the brake controller in your truck, how to set the gain and how to test the breakaway switch.4 partsManualRoof and sealsWater is the biggest enemy of an RV. How to check the roof and seams, which sealant to use and the signs of a leak.4 partsManualThe toiletHow to flush, what paper to use and how to keep the black tank from clogging or smelling.4 partsManualPropane, smoke and CO alarmsWhere each alarm is, what each one means, how to test them and why the propane alarm sometimes beeps on a low battery.4 partsManualSolar and lithium batteriesHow solar charges your batteries, what lithium changes, and how to tell how much power you really have left.4 partsManualTowing a car behind a motorhomeWhich cars can be towed four down, the gear you need, and the steps before and after every tow.4 partsManualWeight and payloadWhat GVWR, cargo capacity and tongue weight mean, how to weigh your rig, and why sway almost always starts with weight.4 parts
Call us Text us