Tag Archives: RV AC

RV Air Conditioning Troubleshooting Tips

12 Wednesday Jun 2024

Posted by in RV Information, RV Newbie, RV Safety, Tech Tips, Tips & Tricks

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Your RV air conditioner is crucial for camping in comfort during the summer months. Unfortunately, these units need repairs once in a while. If your RV AC is giving you problems, try the troubleshooting tips below to get it back up and running.

Lack of Power

If you don’t have any power at all to the AC, there are a couple of simple things you should try before you panic.

Plug-In

First, check your RV plug. Make sure it is plugged all the way into the outlet and there is no damage to the cable going into the RV.

Flip the Breaker

You’ll also want to check the breakers both at the power pole and in the RV breaker box. If a breaker is flipped, switch it back.

Warm Air

Having issues with warm air coming from your RV AC? Here are a couple of things to look at as you try to narrow down the issue.

Check the Capacitors

A capacitor could very well be the culprit. Make sure you discharge your capacitors completely using a discharge tool before testing each one with a multimeter. A bad capacitor is something you can probably replace on your own.

Check the Compressor

It’s also possible for a compressor to cause this issue. Test your compressor with the multimeter. If it is your problem, you’ll want to replace the entire AC unit rather than attempting to replace the part.

Weak Airflow

Warm air is bad, but so is weak airflow. Here’s what you need to test if you don’t have enough air coming from your RV air conditioner.

Look for Freezing

A frozen RV AC will put out very little air. To fix, turn the air conditioner to fan-only mode and run it on high until the ice in the unit melts. If the air conditioner continues to freeze up, you may need to clean the coils and filter.

Look for Clogs

Another problem to look for? Clogged coils or a super dirty air filter. Clean both and then test the unit to see if the airflow gets stronger.

Cover Cracks and Holes

Use a flashlight to take a peek at your ductwork. See a place where air could be escaping? Cover it with metal tape and/or styrofoam to see if that improves things.

Check the Fan

Obviously, it could be that the fan is having issues. Try cleaning and oiling the fan. If this doesn’t work, it might be time for a fan motor replacement.

Excessive Cycling

If your compressor is cycling on and off often, you’re probably dealing with a unit that doesn’t cool properly. Here are some steps to take.

Check the Capacitors

The capacitors will need to be tested in this case as well. Just make sure you discharge them first. If you find that one is bad, replace it.

Look for Ice

Once again, freezing could be the problem. If you find ice in your AC, use the tips above to defrost it and then clean everything to ensure the problem doesn’t return.

Have Parts Professionally Tested

Unfortunately, the other likely surprises are a bad thermostat or a bad control board. It’s best to call a pro in to fix these things.

Dripping Water

Sometimes water will drip from an RV air conditioner. This is never a good thing, but can have a few different causes.

Clean the Drain Pan

A clogged drain pan doesn’t allow water to run where it is supposed to. Instead, it will sometimes run into your rig. Fix this by cleaning the pan and removing the clogs.

Clean the Coils

A unit that freezes up will send bits of water to the floor as the frozen coils thaw out. Clean the coils and filter to try to prevent freezing.

Tighten Things Up

If your AC mounting bolts are loose, they will not hold the gasket snugly in place. This will allow rainwater to find its way under the gasket and into the RV. Tighten the bolts to fix the issue.

Smelly Air Conditioner

RV air conditioners can develop a cave-like smell if the coils or filter become too dirty. Wash both of these things to get rid of any musty smells that may be bothering you while running the AC.

Weird Noises

Pretty much every RV air conditioner out there is going to make some noise. That said, if your AC starts making a new weird noise, you will want to investigate.

Check the Fan

First, check to see if anything is in the way of the fan. Clean the fan and add a bit of oil. If this doesn’t fix your problem and you’re certain the fan is making the noise, you’re probably looking at replacing the fan entirely.

Get Rid of Vibrations

Vibrations on the roof will definitely cause some strange noises inside your RV. Make sure the AC shroud is bolted down tight so it can’t vibrate on the rooftop.

Test the Compressor and Capacitors

While the fan is usually the culprit when it comes to weird AC noises, the compressor or capacitors can make sounds if they are going out. Test both to make sure they aren’t your problem, making sure to discharge the capacitors beforehand.

There you have it, everything you need to know about RV air conditioner troubleshooting. Now you can solve your AC problems and camp in comfort all summer long!

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About the author: Chelsea Gonzales

Chelsea has the amazing opportunity to take part in full-time RV living and traveling with her tiny tribe. She homeschools her five-year-old son as they travel, and takes full advantage of their unique situation by using the entire world as her son’s classroom. A group of total Disney fanatics, Chelsea and her family often find themselves in the Orlando area in order to visit the Disney parks, but they have also visited over 25 of the 50 states with plans to see many more along the way. No matter where her travels take her, Chelsea enjoys riding bikes, gazing at beautiful sunsets, finding new coffee shops, Irish dancing, and sitting around a campfire with her family.

You can join her adventures through her blog, Wonder Wherever We Wander.

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Hot Enough For You?: Air Conditioning Maintenance To Help Keep You Cool.

05 Wednesday Jul 2023

Posted by in Tech Tips, Tips & Tricks

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Summer Solstice is behind us the temperatures have been climbing! At home, with your car or truck, it would be time to have a technician check your coolant and recharge it. However, the roof air conditioners in RVs are a completely sealed system with no ports to check or recharge anything. But there are some maintenance items you can do to make your roof air conditioner run more efficiently.

Clean The Filter, Evaporator, and Condenser Coils.

Whether you have a direct flow air conditioner or one that is ducted throughout the ceiling, they all have a filter that needs to be cleaned periodically. Typically it is in the cold air return and is a woven plastic that can be washed with soap and water. Make sure that it is thoroughly dry before putting it back as a wet filter can mold or restrict airflow.

When you pull the vent, from the return air, down to access the filter you should be able to see the evaporator coil from the inside. The interior air is pulled up through the return air vent by the fan motor and it passes through the evaporator coil where the coolant flashes and draws out heat and moisture. It can also get clogged with dust and other items that make it past the return air filter. The image below is a unit that quit working and we pulled off the top cover and the evaporator shield and found it caked with body powder!

You should be able to use a shop vac to clean the coil from the inside. Otherwise, you would need to get on top of the unit and take the plastic cover and evaporator metal cover off to access it. You must have clean airflow through the coils for the unit to cool.

On the back side of the air conditioner is the condenser coils which draw outside air through the fan motor and help cool the hot copper tubing of the coolant as it makes its way back to the compressor. This needs to be clean and the coils or fins straight. Some models are exposed to the elements and hail or branches can flatten them restricting airflow. Some models have redesigned the condenser coils at an angle to reduce exposure to hail and branches.

Check Airflow At The Unit And At The Vents

Most air conditioner manufacturers make a model that can either be used as a direct vent out of the unit like a window air conditioner in a house, or can have a baffle placed in the cavity to divert air to the ductwork placed in the ceiling. If you have a direct vent model coming down from the unit, check to make sure there are no obstructions such as insulation blocking the flow of air.

If you have a ducted model, it is important to check the diverter or baffle as the air conditioner manufacturers send a generic size and the RV manufacturers are required to cut it to length and fasten it. I have seen several units where the baffle was cut too short, a single piece of duct tape was fastened to the top, and the baffle was actually laying sideways, so very little air was getting back to the vents. If the baffle is not cut to length or the sides are also secure, air will circulate in the cavity and just return back through the return air and sometimes gets so cold it will shut down the system as there is a thermistor or temperature sensor at the evaporator coil. It is important to inspect the entire system as you might need to add HVAC duct tape to reinforce areas that have gaps and loose ends. This is a unit on a 2015 Thor Challenger and although the baffle looks good, there are gaps on the side and top that should be sealed reduce leakage.

I recommend getting an anemometer with an airflow and temperature gauge. Your roof air conditioner can only cool the incoming air at the return air vent 16 degrees so if you let the rig sit in sweltering heat in the summer when not in use and fire it up to cool things down, you will not be very satisfied. If the temperature inside the rig is 100 degrees, the air coming out of the vent will only be a balmy 84 degrees! So having the correct temperature data is important when it comes to troubleshooting. I also like the airflow tester as it tells me the highs and lows of certain vents. Naturally, the vent closest will have a higher CFM (cubic feet per minute) however you should be able to tell if there is a difference between the front and the back.

Some designs are just not very efficient due to the boxed design of the cavity, and instead of providing the maximum airflow to the vents, it creates a circulating effect that provides insufficient airflow and cooling which oftentimes causes condensation as the cool moist air hits the metal sides and ductwork. You can add additional insulation to the sides and create a “V” shaped design, however, a company called RV Airflow has designed a ready-made insert that increases airflow and efficiency. This product captures 100% of the airflow and directs it to the ductwork as well as reducing friction which reduces the stress on the unit which can prolong the life of the compressor and motor as well as reduce noise. You can find the design that fits your model here.

Reduce Initial Start Up Amps

When your roof air conditioner starts the cycle it can draw up to 40+ amps for each unit! This is a quick spike that typically doesn’t trip the 30 amp breaker but does weaken components over time. However, if you have two roof AC units and they start the cycle simultaneously on a 30 amp service, you will have a problem. AND…if you are getting your rig ready for a trip and have it parked at home, plugged into a 20 amp outlet in the garage… another problem.

The Softstartrv is a product that is installed on the air conditioner and will reduce the initial amp draw down to approximately 14-18 amps which help with energy management but also extend the life of the compressor and motor. You can find information on how to install and purchase here.

About the author: Dave Solberg: Managing Editor, RV Repair Club

For the last 25 years, Dave has conducted RV maintenance and safety seminars, developed dealer and owner training programs, written RV safety and handyman articles authored an RV handbook reference guide, and logged over 100,000 miles on the road in an RV.

RV Repair Club

RV Repair Club is your go-to online resource for enthusiasts who want quality RV maintenance, repair and upgrade information – a community where passionate RVers can come together to gather knowledge and share their experiences.

Learn more about RV Repair Club.

David P. ~ “I had to use the Coach-Net system for a coach jack problem.  Pat helped me resolve the issue.  He was very helpful and I was able to continue my journey.  This was the first time I had to use it and it worked out great.  When the time to renew, I most definitely will.  Thanks again for the help.”

Effective Tips For Increasing Your RV Air Conditioner Efficiency

03 Wednesday Aug 2022

Posted by in Tech Tips

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With record temperatures hitting almost every part of the nation, I’m getting quite a number of questions on how to make the old Coleman and Dometic roof air conditioners cool more efficiently. I know we have featured this in the past however, there are some new products on the market as well as a little trick I found when it comes to the standard air diverters in ducted roof air conditioners.

First, Regular Maintenance

Most RV owners don’t know there is some maintenance required to keep the roof AC running efficiently. After all, they never had to do anything to their unit at home why is it any differently? Let’s take a look at how the RV roof air conditioner works and what we can do periodically to help it work as designed.

When the thermostat calls for cooler air, the motor starts in the system and draws the warm, moist interior air up through the air return in the ceiling.

 

Whether your unit is a direct flow like this older unit or it is ducted throughout the ceiling, the air return will have a thin filter to catch dust, dander, or other objects. This filter must be checked and cleaned periodically or it will block airflow and not only make the unit run less efficiently but could ruin the compressor and motor.

The warm moist air comes up through the return and is pulled through the evaporator coil at which time the coolant has been sent from the compressor and “flashes” which pulls heat out and moisture. The evaporator coil needs to be checked and cleaned periodically as well.

Here is a unit from the local campground that stopped working. The evaporator coil was caked with body powder! This unit sat directly above the bedroom area where the owner created a cloud of powder every morning! The evaporator needs to be checked and cleaned at least once a year. You can access this from the inside by pulling off the return air shroud and looking up through the hole.

This is what a good evaporator coil should look like. You can use a small portable vacuum to clean the coils however if they are really dirty, you will need to go up on the roof, take off the shroud, and then take off the evaporator housing and clean it. If you use a garden hose, cover the return air vent or you will get water inside the rig. If you get water or moisture spraying out when the air conditioner is blowing, it could be the drain holes are plugged and moisture is trapped in the drip pan. Check these periodically as well.

Next, the coolant flows back to the condenser coil where outside air is drawn into it down so it can go through the cycle again. Even with 110-degree outside heat, the air drawn in is much less than the high temperatures the coolant can reach. Make sure the condenser fins are not blocking airflow and are straight. It’s not uncommon to see flattened fins from hail or tree branches especially the older units with flat open backs. Some manufacturers are putting them at an angle or in a circle with a covered vent.

Create Inside Airflow

The roof air conditioner of your RV can only cool or “condition” air down 16 degrees from what it is pulling in. As your unit sits in the sweltering sun, inside temperatures can get 20-30 degrees hotter than the outside temperature and sometimes even more. And since hot air rises, the temperature at the inside ceiling of your rig could be 120 degrees! That means your roof air conditioner will pull it in and blowback 104 degrees into your rig. Use your roof vents, windows, and fans to move air around and pull as much warm moist air out as possible if your rig is sweltering.

Create A More Efficient Ducted Airflow

If you have a direct flow unit in which the air comes directly out of vents on the unit, there is not much you can do to improve the airflow as it is basically dumped out like a residential window air conditioner. However, if you have vents in the ceiling and air is distributed from the unit through ductwork there are some modifications you can perform.

Both ducted and non-ducted roof airs are basically the same unit with a few additional components. For ducted models, the unit is shipped with a generic baffle or thin piece of material, typically foam that the manufacturer needs to cut to length and insert into the opening. This is what diverts or directs the air coming from the fan to the ductwork rather than vents on the bottom of the unit.

Here is the diverter on a 2015 Thor Challenger we worked on recently. Notice the back of the unit, behind the diverter, has a side duct going back to the vents. Also, notice all the gaps above and on the side of the diverter! This allows air to blow back into the air return rather than going to the ductwork. Also, when the air comes off the fan it goes straight down and hits the shroud or plastic cover it creates a whirlwind effect and again, limits the airflow. All these gaps and connecting points can be covered with duct sealing tape that you can get at any home improvement store. I would even suggest getting the insulated foam tape and covering all exposed metal as this will also create condensation if left exposed.

To help even further, RV Airflow Systems has developed an aftermarket kit that can be installed to take away the whirlwind effect and increase airflow by 40%. At least that is what they claim. Next month we will be installing one on this unit and will let you know how well it works but it does make sense! You can find more information on their website here: rvairflow.com/collections/all

Lower Your Initial Amp Draw And Use Two Roof AC Units

When the thermostat calls for cooler temperatures and your unit’s motor and compressor kick in, the initial amp draw can be as high as 50 amps or more. Normally that is more than a 30 amp circuit at a campground could handle however, it is just for a short amount of time and typically does not blow the breaker at the pedestal. But it does limit you from using two roof air units on a 30 amp service if they both kick in at the same time. Plus it is a constant issue when you bring the rig home to get it ready for the next camping trip and plug it into a 20 amp garage outlet. Also, if you have a trailer and are using a portable generator rather than shoreline power, you can’t use one of the smaller units just because of the high amp draw at start-up.

Last month we installed and tested a new product called Soft Start RV that reduces the initial amp draw by almost 70%. It also eliminated the annoying “thumping” at start-up and our initial tests showed a startup amp draw of only 10 amps! It is easy to install with just 6 wires and no cutting of any existing roof air conditioner wires. If you can crimp on a few spade connections and get on the roof, you can install this in less than 1 hour. And they have excellent USA-based technical support!

Just a note: SoftStartRV or any other amp reduction product on the market will not make your roof air conditioner run more efficiently during normal operation. It is just during the initial start-up which has a high amp draw.

Check out the video and get a $30 discount through the RV Repair Club here.

About the author: Dave Solberg: Managing Editor, RV Repair Club

For the last 25 years, Dave has conducted RV maintenance and safety seminars, developed dealer and owner training programs, written RV safety and handyman articles authored an RV handbook reference guide, and logged over 100,000 miles on the road in an RV.

RV Repair Club

RV Repair Club is your go-to online resource for enthusiasts who want quality RV maintenance, repair and upgrade information – a community where passionate RVers can come together to gather knowledge and share their experiences.

Learn more about RV Repair Club.

Adam H. ~“We had a tire blowout.  I want to thank the staff at Coach-Net for their quick response in finding an excellent tire shop with the correct size and brand very quickly. Communication with Coach-Net, the tire shop and us was excellent.  A bad day turned out pretty well as we were back on the road very quickly thanks to your help!”

A Beginner’s Guide To HVACs For RVs

24 Wednesday Feb 2021

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A Beginner’s Guide To HVACs For RVs

Last year saw record numbers of people becoming proud RV owners, with more than 40,000 vehicles shipped in June 2020 alone. If you’re new to the RV lifestyle, you may be wondering where to start with some of the terminology and information on offer. This guide to HVACs is designed to give you the confidence to run and maintain these essentials so that you can brave winter chills and keep your cool in the summer with ease.

What’s an HVAC?

Your RV’s HVAC is the Heating, Ventilation, and Air Conditioning system, similar to what you may have at home. Part of the joy of RV ownership is the freedom it gives you to travel and explore: 90% of RV owners take three or more mini-breaks per year in all sorts of weather conditions, so it’s important to be able to keep the temperature to your liking. This leaves you feeling relaxed and comfortable enough to take in the views and make memories with your family in style.

Keeping Your Cool

Since 2020 saw one of the hottest summers on record, you may be most concerned with the air conditioning in your new RV. The unit for this is likely to be stored in a rooftop box, which maximizes space inside your vehicle. Air conditioning power is measured in BTUs (British Thermal Units). The higher the rating, the more powerful the air conditioning. Put simply, the system picks up hot air in the RV and passes it via refrigerants – chemical coolants – which take the heat from it. The process converts gases to liquids and vice versa, so it’s crucial that you clean the unit regularly to reduce the risk of mold building up inside. While you may find it helpful to fit a hygrometer to measure humidity (another factor for causing mold), your RV will already be fitted with a digital or analog thermometer. Some can be zoned so that the temperature in different parts of the RV can be controlled independently.

Winter adventures

Since many RV owners love to hit the road come rain or shine, spending three or four weeks a year in their vehicle, RVs are also equipped with heating and insulation to cope with colder weather. The warm air will either be produced by a heat pump, which uses electricity, or a furnace, which runs on propane. Your heat pump is likely to be located in the rooftop AC box. If you are camping somewhere with power, it can be a good idea to plug in and use your heat pump to save on propane, but in extreme cold, the furnace tends to be a more effective and efficient way to keep your RV cozy and warm.

Looking after your HVAC

While Coach-Net is always ready to help its members, with a little maintenance you can ensure that your RV is always as ready for adventures as you are. Use a handheld vacuum to clean dust from your HVAC’s vents regularly. For the AC unit, check for signs of fluid leakage, and ensure that you clean the filters regularly too. If your RV has a propane furnace, ensure that you have a carbon monoxide detector fitted in your vehicle and that the batteries are up to date. Finally, on the occasions when you are carrying out rooftop maintenance, keep an eye on the condition of the plastic casing in which the AC unit sits.

Owning an RV opens the door to all sorts of trips, but it can feel a little daunting as you get to grips with how best to take care of it.  Systems like your RV’s HVAC are there to make your journeys more comfortable, so it’s important to learn how to control the settings to your preferences, and to maintain the system so it can continue to look after you. Now, you’re free to explore – whatever the weather.

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Installing a Maxx Air Vent Cover

12 Tuesday Mar 2019

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Installing Maxx Vent

While many RVs these days come equipped from the factory, or the previous owner, with Maxx Air vent covers installed, it is not always the case. Vent covers are handy to have, as they allow you to have your vents open while travelling or when it’s raining. This allows you to have fresh air circulating through your rig without necessarily having your windows open or air conditioner running.

Vent covers are very simple to install and make for a great beginner DIY project. In this article I will walk through the installation of the Maxx Air vent cover, including a slight departure from the installation instructions that make it even easier!

Note that roof vents that incorporate large exhaust fans, such as Fantastic Fans® require different models of vent cover that allow higher air flow. Be sure to consult your RV parts dealer or the Maxx Air (or equivalent) website for specific application information. However, the installation process will be similar to that shown here.

Once you have your Maxx Air cover (or any other brand), unpack the contents of the packaging and separate the hardware from the cover. You should have a set of angle brackets, carriage bolts, washers, nuts, and some machine screws. If you want to make the job slightly easier, acquire four #8 x 5/8 (or similar length) self-tapping screws, which don’t come with the kit. These will replace the machine screws and nuts.

Any 14” roof vent can be covered by a vent cover. The following steps will illustrate how the installation is performed:

Air Vent

  1. The first step is to place the cover over the vent for proper positioning. Ensure the open, vented side of the cover is facing the rear of the coach. Center the cover side-to-side but leave more clearance at the back of the cover to allow the non-hinged edge of the vent to swing open and closed without binding.
  2. Once you have the cover positioned, go inside the RV and wind the vent up and down to make sure it has clearance across the full range of motion.
  3. When you have verified proper positioning and clearances, make a mark on the RV roof at each of the four corners where the bolt holes appear on the cover. Use either the inside or outside holes, but not both.
  4. Remove the vent cover and place a bracket at each marked location as shown. Be sure to insert the carriage bolt through the bracket before placing the bracket against the vent frame. Make sure the slot for the carriage bolt is located inline with the mark made in the previous step.
  5. Here, the manufacturer instructions may call for drilling a hole through the vent frame to install the machine screws. A much easier option is to simply screw a self-tapping sheet metal screw through the frame as shown here. As indicated above, a #8 screw approximately 5/8” in length will suffice. A battery powered screwdriver or drill is required here, but make sure you don’t over-torque the screws. Repeat this process for all four brackets.
  6. Once all four brackets have been secured to the vent frame, place the cover over the vent, making sure all four carriage bolts go through the cover slots. Slide the bolts in the bracket to achieve proper alignment. Go inside the RV and check for clearances again, as the vent cover can still be shifted in the slots.
  7. Once final clearance has been confirmed, place the star washers, flat washers, lock washers, and nuts on the carriage bolts and tighten the nuts using a socket or wrench.
  8. Since no holes were drilled in the RV roof, no sealant is required.

With this do-it-yourself task accomplished, you can feel satisfied that you have saved money, and it may give you the confidence to attempt other basic, or even more advanced projects.

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RV Air Conditioning Tips

19 Wednesday Sep 2018

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RV Air ConditioningThere are some tips and tricks to making your roof AC run more efficiently and provide a cooler interior climate.

Become Familiar With Your Roof AC

The first thing to do is become familiar with how the roof AC operates and what you can expect.  Most RVers think the roof AC uses a coolant such as Freon to “dump” cold air into the rig but this is not the case.  The roof AC operates very similar to your absorption refrigerator and actually draws heat from interior air through the evaporator at the front of the unit.  Warm and humid interior air is drawn up to the roof AC through the return air vent, passes over the evaporator coil and heat and moisture is extracted from it.

If you were to take the cover off the roof AC unit and the evaporator shield you would see the evaporator fins getting very wet immediately and the moisture forming at the bottom on the drip pan.  The compressor does just that – compresses the coolant and pushes or pulls it through tubes known as the low side and high side which changes it from a liquid to a vapor.  This in turn draws moisture and heat in the evaporator and the air is then circulated back into the rig just behind the evaporator coil by the blower fan.

Evaporator

Evaporator

Blower Fan

Blower Fan

Compressor or Pump

Compressor or Pump

The coolant passes through the back condenser fins where the blower motor draws exterior air in and over the coils with the Freon.

Condenser

Condenser

With an understanding of how the system works, it’s important for owners to do a little bit of maintenance so there is proper air flow, sufficient amperage, and no air leaks in the system.

Proper Air Flow

The return air coming from the inside to the evaporator will have a filter. Roof-mounted units with the conditioned air coming directly out of the bottom will have the filter designed into the ceiling shroud.

AC Filter (non ducted)

AC Filter (non ducted)

Units with ducted air vents in the ceiling will have a grill on the ceiling.

AC Filter (ducted)

AC Filter (ducted)

These filters should be cleaned at least once a year and typically more depending on usage and how much dust might be in the air.  Most dealers indicate a dirty filter is over 50% of the issues with a roof AC cooling inefficiency!

Next, make sure the vents are open and operating properly on a ducted roof AC system.  Closed vents will restrict air flow, causing high amp draw and condensation.

  • Check and clean the condensor and evaporator coil every year.
  • Dust, pet hair, and even body powders can get pulled into the return air and clog the coils.
  • There are specific cleaners for the evaporator and condensor coils that should be used each year.
  • Since the evaporator coil is in the front and goes directly to the opening for cool air to the rig, you will need to do a low pressure clean and have a plastic sheet over the blower fan return to keep moisture from entering the rig.
  • Do not use high pressure water as it will not only make a mess, but will damage the coils.
  • Once the coils are clean, make sure they are straight and will allow good air flow.  There are even brushes or combs available to help straighten the fins on the coils.
  • Typically the evaporator coils do not get damaged, rather clogged, however the condenser coils are exposed to the outside and can get hail damage or even tree branches.

Proper Amperage

The roof AC and several other appliances run on 120-volt power which is supplied from the shoreline connection or a generator to the distribution center.  Most RV owners take it for granted that the campground connection is a 30 amp 120-volt power system and they will have no problems just like they did at home.  Unfortunately, the campground source is not as reliable as a residential system and can have severe power loss situations.  If the power drops below 110-volts, the roof AC unit will not be able to function at 100% capacity and even though you hear the fans running and other components, it will not be able to draw the heat out and efficiently cool the unit.   This is why a Surge Guard protection unit is a good idea as it will monitor the incoming voltage.

Air Leaks

Your roof AC unit is mounted with a gasket between the unit an the roof typically with 4 spring loaded fasteners that should be checked for specific torque or tightness every year.  You should be able to find the torque specs in the roof AC owner’s manual however a good hand tightening should be good.  If the gasket is not tight, you will get hot moist outside air coming into the unit and rig which will make it difficult to condidtion the exiting air.  Also, check to make sure you are not getting hot and moist outside air from vents, windows, and event roof ducting.  Seal all the leaks during hot and humid conditions and your roof AC will work more efficiently.

The roof AC can only cool the return air from the inside down about 20 degrees, so if the inside of your rig is 100 degrees, you will only get 80 degrees air back inside!  So the key is to try and keep the inside air temperature as low as possible so the roof AC can run more efficiently.

About the author:

Dave Solberg: Managing Editor, RV Repair Club

For the last 25 years, Dave has conducted RV maintenance and safety seminars, developed dealer and owner training programs, written RV safety and handyman articles, authored an RV handbook reference guide and logged over 100,000 miles on the road in an RV.

RV Repair ClubRV Repair Club is your go-to online resource for enthusiasts who want quality RV maintenance, repair, and upgrade information – a community where passionate RVers can come together to gather knowledge and share their experiences.

Learn more about RV Repair Club.

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Brett P. ~ “So glad we decided to get Coach-net. First trip in the RV and needed it. Coach-net was a life saver.”

Beat The Summer Heat

16 Thursday Jul 2015

Posted by in RV Information, Tech Tips

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Beat-The-Summer-HeatAlthough there have been several articles written about RV maintenance, including my own, some of them fail to address the maintenance requirements of the rooftop air conditioner. This is mainly because for the most part this appliance requires very little attention. With the arrival of the hot days of summer (for many of us), spending some time performing simple maintenance on the AC unit will ensure you keep a cool rig.

I’ll start off with a primer outlining how the air-conditioner works. Like the fridge in your home, the AC unit works on the principle of the Refrigeration Cycle. The primary components of the air conditioner are the refrigerant, compressor, condenser, expansion valve, evaporator, and connecting tubing. The entire cooling process follows the laws of thermodynamics, which are outside the scope of this article. It is enough to mention that a liquid changing state to a gas absorbs heat, whereas a gas changing to a liquid sheds heat.

refrigeration-chartThe cycle starts at the compressor, where low-pressure refrigerant gas is compressed to high-pressure. This flows through the condenser, where it sheds heat to the outside of the RV as it changes state into liquid. The liquid is metered through the expansion valve where the pressure is lowered. This liquid then enters the evaporator, which has the warm RV interior air flowing over it. As the liquid refrigerant flows through the evaporator, it absorbs heat from the surrounding air as it is converted back into low-pressure vapor. The cooled air is returned to the interior of the RV.

This refrigeration cycle runs continuously, with the refrigerant constantly changing state from vapor to liquid and back again. The system will continue this process for many years with only minimal maintenance.

There are really only three main things that you need to do in order to keep your air-conditioner running reliably. The first is to keep the intake filter clean, and be sure to keep it in place at all times. If your AC unit is non-ducted, the filter should be installed on the ceiling shroud between the intake grille and the evaporator coils. If you have a ducted system, there may be a filter in each of the ducted air intakes. Simply wash the filter with water, wring it, and allow it to air-dry before re-installing. If a filter becomes damaged, be sure to replace it with a new one. A dirty filter can impede the flow of air over the evaporator coils and reduce the efficiency of the unit. A damaged or missing filter can allow dust and debris to accumulate on the evaporator. This is not good for an air-conditioner, as debris reduces the heat transfer efficiency and can lead to eventual failure of the system.

Ensure that the condensation that drips off the evaporator (resulting from removing moisture from the interior air) is properly draining away from the AC unit. It is common for leaves or debris to block the moisture drain and flood the air conditioner pan.

The last important maintenance step is to ensure the evaporator and condenser fins are not damaged. Regular inspection of the fins is recommended. If you find crushed or damaged fins, use a fin comb (available at larger RV parts retailers), dental pick, or other appropriate tool to straighten them.

About the Author:

Steve Froese, an avid RV owner, traveler, and  Coach-Net member since 2013, is the principal of “A Word to the Wise Technical Communications”, a published RV author, certified RV technician, and licensed Professional Engineer. He frequently collaborates with the “RV Doctor”, Gary Bunzer, and has worked with the RVIA/RVDA as a technical and training writer and consultant. Professionally, he works as a quality engineer and musician. Watch for more of Steve’s work in upcoming Coach-Net publications.

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