Carrier RV Air Conditioner How to and Troubleshooting Guide

Carrier RV air conditioner units are two-piece systems, consisting of the upper unit and ceiling unit. The upper unit contains the refrigeration system while the ceiling unit contains the controls and vents. Ceiling units are available in a free-blow or ducted configuration. These models include cooling-only units (free blow or ducted air delivery), heating/cooling units, and heat pump units. Cooling units with heat strips are available for free blow only.

The operation of the units is controlled automatically by the temperature controller (thermostat), which maintains the interior temperature of the vehicle at the desired set point. Free blow, cool-only units are available with a wall-mounted thermostat.

Your Carrier RV air conditioner, just like other air conditioning units, can experience trouble in the cause of its operation.  When this happens, it can be really frustrating not knowing what to do to get it to work properly. Luckily many of the issues with these units can be resolved quickly through simple troubleshooting procedures. In this guide, we are going to show you just what you need to do to fix problems you may be having with your unit, as well as offer solutions to common Carrier RV air conditioner challenges.

How a Carrier RV Air Conditioner Works

Standard system

The cooling cycle is energized when the thermostat, located on the ceiling unit, calls for cooling. The main components of the system are the compressor, air-cooled condenser coil, strainer, capillary tube, evaporator coil, and accumulator.

The compressor raises the pressure and the temperature of the refrigerant and forces it through the discharge line into the condenser coil. The condenser fan circulates surrounding air (which is at a temperature lower than the refrigerant) over the outside of the coil tubes.

Heat transfer is established from the refrigerant (inside the tubes) to the air (flowing over the tubes). The tubes have fins designed to improve the transfer of heat from the refrigerant gas to the air. This removal of heat causes the refrigerant to liquefy, thus liquid refrigerant leaves the coil and flows through a strainer to the capillary tube. The strainer removes any impurities within the refrigerant system.

The capillary tube meters the flow of liquid refrigerant to the evaporator coil. As the refrigerant flows through the capillary tube, there is a reduction in pressure and temperature.

The evaporator blower (fan) pulls vehicle air through the filters, which remove particulate matter and then pass the cleaned air through the evaporator coil. The low pressure, the low-temperature liquid that flows into the evaporator coil tubes is colder than the air that is circulated over the tubes. Heat transfer is established from the vehicle air (flowing over the tubes) to the refrigerant (flowing inside the tubes).

The evaporator coil tubes have aluminum fins to increase heat transfer from the air to the refrigerant; therefore the cooler air is circulated to the interior of the vehicle. The transfer of heat from the air to the low-temperature liquid refrigerant in the indoor coil causes the liquid to vaporize. At this low temperature, the low-pressure vapor passes into the accumulator. The accumulator is designed with the inlet tube delivering refrigerant to the bottom of the tank and the outlet tube taking refrigerant from the top of the tank. This arrangement ensures that only vapor refrigerant is returned to the compressor, where the cycle repeats. When ventilation only is selected, the indoor fan functions to circulate air throughout the vehicle. The refrigerant cycle will remain off.

Heat Pump

Cooling

The cooling cycle is energized when the thermostat, located in the ceiling unit, calls for cooling. The system controls are positioned for “normal” refrigerant flow, with the compressor discharge delivered to the outdoor coil and liquid delivered to the indoor coil. The main components of the system are the compressor, reversing valve, air-cooled outdoor coil, strainer, capillary tube, indoor coil, and accumulator.

The compressor raises the pressure and the temperature of the refrigerant and forces it through the discharge line and reversing valve into the outdoor coil. The outdoor fan circulates surrounding air (which is at a temperature lower than the refrigerant) over the outside of the coil tubes.

Heat transfer is established from the refrigerant (inside the tubes) to the outdoor air (flowing over the tubes). The tubes have fins designed to improve the transfer of heat from the refrigerant gas to the air; this removal of heat causes the refrigerant to liquefy, thus liquid refrigerant leaves the coil and flows through the strainer to the capillary tube.

The strainer removes any impurities within the refrigerant system. The capillary tube meters the flow of liquid refrigerant to the indoor coil. As the refrigerant flows through the capillary tube, there is a reduction in pressure and temperature.

The indoor blower (fan) pulls inside air through the filters, which remove particulate matter and then pass the cleaned air through the indoor coil.

The low pressure, the low-temperature liquid that flows into the indoor coil tubes is colder than the air that is circulated over the tubes. Heat transfer is established from the indoor air (flowing over the tubes) to the refrigerant (flowing inside the tubes). The indoor coil tubes have aluminum fins to increase heat transfer from the air to the refrigerant; therefore the cooler air is circulated to the interior of the vehicle.

The transfer of heat from the air to the low temperature liquid refrigerant in the indoor coil causes the liquid to vaporize. This low temperature, low pressure vapor passes into the accumulator. The accumulator is designed with the inlet tube delivering refrigerant to the bottom of the tank and the outlet tube taking refrigerant from the top of the tank. This arrangement ensures that only vapor refrigerant is returned to the compressor, where the cycle repeats.

When ventilation only is selected, the indoor fan functions to circulate air throughout the vehicle. The refrigerant cycle will remain off.

Heating

The heating cycle is energized when the thermostat, located in the ceiling unit, calls for heat. The system controls are positioned for “reverse” refrigerant flow, with the compressor discharge delivered to the indoor coil and liquid delivered to the outdoor coil.

The main components of the system are the compressor, reversing valve, indoor coil, capillary tube, strainer, air-cooled outdoor coil, and the accumulator.

The compressor raises the pressure and the temperature of the refrigerant and forces it through the discharge line and reversing valve into the indoor coil.

The indoor blower (fan) pulls inside air through the filters, which remove particulate matter and then pass the cleaned air through the indoor coil.

The vehicle air (which is at a temperature lower than the refrigerant) passes over the outside of the coil tubes. Heat transfer is established from the refrigerant (inside the tubes) to the vehicle air (flowing over the tubes). The tubes have fins designed to improve the transfer of heat from the refrigerant gas to the air; this removal of heat causes the refrigerant to liquefy, thus liquid refrigerant leaves the coil and flows through the strainer to the outdoor coil. The strainer removes any impurities within the refrigerant system.

The capillary tube meters the flow of liquid refrigerant to the outdoor coil. As the refrigerant flows through the capillary tube, there is a reduction in pressure and temperature.

The low pressure, low temperature liquid that flows into the outdoor coil tubes is colder than the outdoor air that is circulated over the tubes. Heat transfer is established from the outdoor air (flowing over the tubes) to the refrigerant (flowing inside the tubes). The outdoor coil tubes have aluminum fins to increase heat transfer from the air to the refrigerant.

The transfer of heat from the air to the low temperature liquid refrigerant in the outdoor coil causes the liquid to vaporize. This low temperature, low pressure vapor passes into the accumulator. The accumulator is designed with the inlet tube delivering refrigerant to the bottom of the tank and the outlet tube taking refrigerant form the top of the tank. This arrangement ensures that only vapor refrigerant is returned to the compressor, where the cycle repeats.

When ventilation only is selected, the indoor fan functions to circulate air throughout the vehicle. The refrigerant cycle will remain off.

How to Operate a Carrier RV Air Conditioner

Use the following operating instructions for your Carrier AirV unit:

OFF

When the dial is turned to the OFF position the unit will not operate. When leaving your vehicle for any period of time, make sure the master control dial is set to the OFF position.

LOW FAN

LOW FAN will circulate relatively small quantities of air without cooling. Choose the LOW FAN setting by rotating the dial to the position.

HIGH FAN

This setting will circulate large quantities of air without cooling. Choose the HIGH FAN setting by simply rotating the dial to this position.

LOW COOL

LOW COOL provides light cooling. To choose the LOW COOL setting, simply rotate the dial to this position. It is also recommended for nighttime use or relatively hot days.

HIGH COOL

This setting provides maximum cooling. To choose the HIGH COOL setting, simply rotate the dial to this position. It is recommended for quick cooling or extremely hot days. Once the room is cooled, switch to lower setting.

HEAT

HEAT will provide comfortable heating. To choose the HEAT setting, rotate the dial to this position. The HEAT option is recommended for cold days.

THERMOSTAT CONTROL

For cooler room conditions rotate the thermostat dial clockwise toward COOLER position. For warmer room condition rotate the thermostat dial counterclockwise toward WARMER position.

AIR SWEEPER CONTROL

The unit provides an automatic air sweep to cool (or heat) the room more efficiently. When the air sweep switch is set on, the horizontal blade moves slowly up and down and distributes the air around the room. The direction of the vertical blades can be adjusted manually (make sure the air sweep is off). With the air sweep in the off position, the horizontal blade can be closed by pushing the PUSH mark on the blade and can be opened by pushing it again.

“AIR SHOWER”

The unit provides you with more efficient cooling air with direct air discharge. On extremely hot days or much activity, you can take an “air shower” and cool off quickly. On a cold day you can enjoy the heated air in the same way.

To enjoy the direct air, rotate the knob to the open position and closing the front or rear horizontal blade. (Closing the front blade may provide direct air more efficiently).

How to Troubleshoot a Carrier RV Air Conditioner

While it is recommended to call an expert to troubleshoot issues with your air conditioner, sometimes you can resolve the problems by performing basic steps. The following are basic troubleshooting steps for your Carrier air conditioner:

Check the thermostat settings

Knowing how to troubleshoot an air conditioner often starts with the main control – its thermostat. Thermostats come in a variety of options, starting with very basic models that simply control heating and cooling temperatures and fan operation to the more sophisticated programmable versions. There are a number of ways your thermostat settings can make it appear that your air conditioner is not running correctly. Symptoms you might notice include:

  • Lukewarm air blowing from the registers/vents at times, and cold air blowing at other times.
  • Higher than expected temperature reading on the thermostat
  • No air blowing from the registers/vents

If you experience any of the above symptoms, be sure to check the thermostat before calling an HVAC repair service.

  • Is the thermostat set for heating instead of cooling the air? If it is, simply adjust the thermostat so it is set to cool, or change the setting to auto so it will automatically change between cooling and heating as temperatures change.
  • Is the fan set on “auto”, “on”, or “off”? If the setting is “on”, the fan will run constantly, even when the system is not cooling the air. This could result in warmer air blowing from the registers when the AC unit is not operating. Changing the fan setting to “auto” will resolve the issue by turning off the blower when the system is not actively cooling. If it is set to “off”, simply select “on” or “auto”.
  • Check the temperature setting to make sure somebody else did not change it to a higher setting.

If after making the above adjustments your system still does not respond, it may be time to contact your local HVAC expert to diagnose.

Air filter is dirty

The next most common step in AC troubleshooting is checking for a dirty air filter. Your AC system is more than just the outdoor unit sitting by the side of your home. Most systems also include an indoor air handler unit, usually a furnace or fan coil. The indoor unit should include an air filter that traps dust, dirt and other airborne particles. Lack of maintenance can lead to a clogged filter and blocked air flow. These can lead to loss of efficiency, discomfort, or in more extreme cases, system failure.

Symptoms of a dirty filter include:

  • The air temperature in your home is warmer than normal
  • Airflow from your cooling registers seems to be less than usual
  • The AC runs for short periods of time before shutting down and re-starting (short cycling)

Before checking your air filter, be sure the thermostat is set for cooling and that the temperature setting is correct. If you still suspect the problem is a dirty air filter, consult your owner’s manual for instructions on removing and cleaning or replacing your air filter. If cleaning or replacing the filter does not solve the problem, contact your local Carrier dealer for assistance.

Low refrigerant level

Your air conditioning system uses a chemical called refrigerant to help cool your home. The refrigerant is pumped through copper tubing, the indoor evaporator coil, and outdoor condensing unit, in a continuous loop. As it flows through your AC system, the refrigerant pulls heat from your home and deposits it outside, leaving indoor air cooler, less humid, and more comfortable.

If refrigerant levels get low, you might experience the following air conditioner issues:

  • Vehicle not staying cool enough
  • System running continuously or for longer than normal cycles
  • AC turning on, then off quickly, several times in a row (short cycling)

If your thermostat settings are correct and your air filter is clean, you may have a leak or other issue that is causing the refrigerant levels to drop. 

Electrical panel issues

If there is no air coming from the registers, the house is too warm, and the system is not running at all, you might have lost power to the system. Your air conditioner runs on electricity, so if it won’t power on, locate the electrical panel (breaker box). Look for a blown fuse or a tripped circuit breaker that is not in the ON position. If it is a blown fuse or a tripped circuit breaker, make sure you are comfortable and competent to safely replace the fuse and/or reset the breaker – if not, consult a qualified professional. Do not attempt to troubleshoot electrical issues yourself. If the circuit breaker trips again (or the fuse blows again) it’s time to call a technician who knows how to troubleshoot an air conditioner with electrical issues.

Frozen evaporator coil

You may have a frozen evaporator coil if you notice:

  • Higher utility bills
  • Inadequate cooling
  • Excessive condensate drainage near your indoor unit
  • Frost or ice forming on the copper refrigerant lines coming from your evaporator coil cabinet
  • Frost forming on exterior refrigerant tubing or the outdoor unit

Issues that can lead to a frozen evaporator coil include:

  • Excessive build-up of dust, dirt or other pollutants on the evaporator coil
  • Excessively dirty or clogged air filter
  • Excessive build-up of dust, dirt or debris on the outdoor condensing unit
  • Low refrigerant levels

Continuing to operate the system with a frozen evaporator coil can cause serious damage to the coil and a potentially costly repair. Because the evaporator coil is typically not easily accessible and troubleshooting an air conditioner’s refrigerant levels should be handled by a professional contractor, we recommend you shut down the system and contact a qualified technician when you have a frozen evaporator, unless you really know what you are doing.

Condensing unit is faulty or broken

It is time to troubleshoot an air conditioner for a faulty or broken condensing unit when you notice issues like:

  • No cooling or inadequate cooling
  • System turning on and off rapidly (short cycling)
  • System running continuously or for unusually long periods of time
  • Frost or ice on the coil or copper refrigerant tubing
  • Condensing unit not turning on at all

As was the case with evaporator coil issues, a condensing unit might have an excessively dirty coil or refrigerant leakage. Additional issues with the outdoor condensing unit might include a faulty compressor, a failing condenser fan motor, or a faulty run capacitor.

Why is My Carrier RV Air Conditioner Running but Not Cooling?

If the unit is not cooling, the temperature setting may be too high. If so, reset the air conditioner to a lower temperature.

Another reason for this problem is that the room was already very hot before the unit was turned on. You need to allow a sufficient amount of time for the unit to heat the room.

If your ducted unit is not cooling and the green LED light flashes 5 times, try the following troubleshooting steps:

  • Check 115 volt AC power source
  • Momentarily disconnect 12 VDC power source
  • Disconnect compressor malfunction test switch.
  • Check AMP draw.
  • Check ∆ T

If the unit cools for a few moments then stops cooling, try these troubleshooting steps to resolve the issue:

  • Remove grille, verify evaporator coil probe is inserted into the coil.
  • Check AMP draw.
  • Check ∆ T
  • Replace the unit.

Carrier RV Air Conditioner Not Turning ON

If the unit is not turning on, it could be that power is not going to the unit. There are several possible causes for this:

  1. The master switch is off. To fix, reset master switch.
  2. Open circuit breaker. If so, reset circuit breaker.
  3. Defective wiring. If so, replace the wiring.
  4. Loose electrical connections. Verify that all connections are tight.
  5. Faulty switches, thermostat, or fan. If there is a defective component, be sure to replace it.
  6. 12 VDC not connected (ducted systems). Connect to 12 VDC power source to resolve the problem.
  7. 12 VDC in-line fuse open (ducted). To fix, replace the fuse.

How to Reset a Carrier RV Air Conditioner

If power to the Carrier RV air conditioner is disrupted three times it will stop working and must be reset. To reset, follow these steps:

  1. Simply disconnect all power to the unit – AC power and DC power. Do that by turning off the AC breaker and then either turn off the battery (if you have a switch) or disconnect the battery.
  2. Wait a few seconds and then turn the battery back on (or reconnect) and then turn on the AC breaker. T
  3. The AC should work – if it doesn’t, try it again and wait a little longer with the power off.

Why Did My Carrier RV Air Conditioner Stop Working?

If your unit is not heating or cooling or heating the room, this can happen because of several reasons:

  1. There could be blockage of the unit’s air output. To fix this, make sure that there are no obstacles restricting or blocking the unit’s output.
  2. The roof top air conditioner is not level. You need to mount the roof top air conditioner as level as possible from front to rear and side to side when the vehicle is parked. Make sure that the mounting of the air conditioner is correct and level.
  3. The air filter is dirty. If this is the case, remove and clean the filter.

How Much Power Does My Carrier RV Air Conditioner Consume?

The power consumption of an air conditioner in RV will vary depending on the BTU rating of the AC. BTU is nothing but an acronym for British thermal unit, which basically measures the heat or thermal energy.

An air conditioner normally will have two watt ratings. The watts required to do the start up and the watts that are consumed by it during running. The start-up watts required are higher as compared to the running watts requirement. Thus, the generator you are using to run the air conditioner should have more watts than the start up watts required by the AC.

The following are the approximate figures for the start up wattage:

  1. On an average a 15,000 BTU Air conditioner needs around 3200 to 3500 watts for start up
  2.  On an average a 13,500 BTU Air conditioner needs around 2700 to 2900 watts for start up
  3.  On an average a 10,000 BTU Air conditioner needs around 1900 to 2050 watts for start up
  4.  On an average a 7,000 BTU Air conditioner needs around 1600 to 1800 watts for start up
  5.  On an average a 5,000 BTU Air conditioner needs around 1100 to 1300 watts for start up

As for the running wattage, the following are the approximate figures:

  1. On an average a 15,000 BTU Air conditioner needs around 1200 to 1700 watts for running
  2.  On an average a 13,500 BTU Air conditioner needs around 1000 to 1300 watts for running
  3.  On an average a 10,000 BTU Air conditioner needs around 600 to 750 watts for running
  4.  On an average a 7,000 BTU Air conditioner needs around 500 to 650 watts for running
  5.  On an average a 5,000 BTU Air conditioner needs around 300 to 450 watts for running

How to Change Carrier RV Air Conditioner from Fahrenheit to Celsius

Remote control

All Remote Control Assemblies in the United States are pre-set to display in Fahrenheit degrees.  Before changing from Fahrenheit to Celsius, you should note that the change will be permanent. It cannot be changed back to Fahrenheit.

To change from a Fahrenheit display to a Celsius display do the following:

  1. Remove the batteries from the remote control.
  2. Carefully remove the remote cover by inserting a narrow flat object between the cover and remote body and prying apart.
  3. Remove the brass screw holding the PCB in place.
  4. Carefully remove the PCB board from the remote body, making sure the battery springs release from their holders.
  5. Locate FR9 on the PCB board.
  6. Carefully cut the FR9 jumper wire.
  7. Reverse above procedure for reassembly.

Thermostat

The Fahrenheit/Celsius selection operates the thermostat in either Fahrenheit or Celsius. To select, follow these steps below:

  1. Enter configuration mode (if not already there).
  2. Use UP & DOWN buttons to display “d”.
  3. Press MODE button once to display current selection of F or C.
  4. Use UP & DOWN buttons to change between F & C.
  5. Press MODE button to return to “d”. UP & DOWN buttons now move between option choices; or press FAN button to exit configuration mode.

Carrier RV Air Conditioner Remote Control Not Working

If your Carrier RV air conditioner remote control is not working, try replacing the batteries in the remote control. If installing fresh batteries does not solve the problem and you can still operate the air conditioner manually, the remote control might be defective. If you think the remote control is defective, replace it.

The problem could also be the main control board. The main control board has an infrared receiver that receives signals from the remote. If the infrared receiver is not working, the remote control will not be able to communicate with the control board. If you suspect the main control board is defective, replace it.

Carrier RV Air Conditioner Leaking Water Inside

If your unit has water dripping inside, the basepan gasket has not been evenly compressed to about 60%. Mounting bolts should be tightened evenly by compressing the basepan gasket to the sixty percent requirement.

If water is dripping from the ceiling unit, verify the vehicle is level, tighten unit mounting bolts evenly or replace unit gasket.

Carrier RV Air Conditioner Compressor Not Engaging

If your Carrier RV air conditioner compressor is not engaging, this could mean that the compressor power supply is open. If this is the case then there are several issues that might have caused this:

  1. The leads at the compressor terminals may have become loose. Check the leads at the terminals and if loose, tighten them.
  2. Defective motor overload switch. Replace switch.
  3. Defective capacitor.

If this is the case, you need to replace the defective capacitor.

To test a capacitor to determine if it is good, open or shorted, you can use an ohm meter. To determine a capacitor’s capacitance, you need a capacitor meter. Capacitors showing signs of leaks or bulging should be replaced immediately.

To troubleshoot a capacitor (upper unit- Standard, HC and HP), follow these instructions below:

  • Disconnect power to the unit before checking the capacitor.
  • Capacitors must be discharged properly before testing.
  • Place a 20,000 ohm, 2 watt resistor across the terminals of the capacitor for approximately 30 seconds.
  • After the capacitor has been discharged and all wires removed from the capacitor terminals, use an ohm meter to test its resistance.
  • Set the scale to R x 1K or 10K ohm and place the ohmmeter leads across the capacitor terminals.
  • If the ohmmeter first reads 0, then rises toward infinity or some higher resistance, the capacitor is good.
  • If the ohmmeter goes to 0 or a low resistance and stays there, the capacitor is shorted and needs to be replaced.
  • If the ohmmeter reads infinity (OL) the capacitor is open and needs to be replaced.

For a Low Profile unit, follow these steps to remove the capacitor:

  • Remove exterior cover assembly.
  • Release the (2) front, (2) rear, (1) left side and (1) right side locking tabs by pulling back on the tabs.
  • Remove the screw (1) from the control box cover.
  • With all (6) locking tabs released and control box screw removed, lift the upper scroll assembly off of the lower scroll assembly.
  • Pull back on and release the 4 locking tabs. There are 2 on each side of the control assembly,
  • Lift control box assembly from lower scroll assembly.
  • Then proceed with the troubleshooting steps as outlined for Standard, HC & HP units above.
  • The Low Profile Capacitor is removed from the control box assembly by pushing on the capacitor from under the control box assembly.
  • Open compressor windings.

 If this is the case, replace compressor.

To replace the compressor (Upper Unit (Roof)- Standard, High Capacity & Heat Pump systems) follow these instructions below. Observe the same procedures for rotary compressors as for reciprocating compressors.

  • Follow all safety codes. Reminder: use protective goggles, work gloves, and water soaked quenching cloth.
  • Remove exterior cover. Disconnect all wiring from the compressor.
  • Apply field-supplied, line-tap-valves to the suction and discharge lines as close to the compressor as possible.
  • Recover the refrigerant charge from the unit. After recovering, cut the discharge and suction line process tubes below the tube crimps. If you choose a good tubing location for cutting the refrigeration lines initially, the location is easily accessible when making the final joints.
  • Connect a nitrogen supply to the unit at one of the line-tap-valve connectors (5-psig maximum flow), leaving the other connector open to the atmosphere. Braze angle valves with stubs to each process tube.
  •  Remove the compressor from the unit (3 bolts). There are 4 bolts with the Roof Low Profile Compressor.
  • Remove line-tap-valves from the suction and discharge lines. Carefully braze the holes closed from where the line-tap-valves were removed.
  • Clean the system: add or replace liquid line filter drier. For proper cleaning and flushing use a UL approved refrigerant recycling system.
  • Install a new compressor and braze into place with field-supplied copper slip couplings.
  • Connect wiring: replace wire terminals if necessary.
  • Proceed with evacuation and charging (15.9 OZ. – .45 KG R22). For the Roof Low Profile unit the system charge is 16.9 OZ. Pinch off lines where angle valves were added. Cut off angle valves above pinch-off, and braze tubes.
  • Start up the unit.
  • Seized compressor. Replace compressor.
  • Capacitor is not wired correctly. Verify capacitor wiring.

Carrier RV Air Conditioner Turns On and Off Repeatedly

When your RV air conditioner kicks on and off and continues this cycle until you turn it off, this can get you all puzzled and wondering what the issue might be. Luckily, you are not the only one that has had to deal with this problem- it is a common issue with several possible causes. Knowing what is making your air conditioner behave that way gets you a step closer to finding a solution.

An RV air conditioner may turn on and off repeatedly because of a number of reasons:

Bad Thermostat

Normally, the air conditioner thermostat is set to the ‘Automatic’ mode, and it is supposed to work fine without any intervention. However, the RV air conditioner turns on and off repeatedly when the thermostat does not function properly.

If the thermostat is not sensing the temperature accurately and communicates misinformation, it will signal the air conditioning system to start and stop frequently.

If you notice your thermostat screen is blank or fading it may be low on batteries and losing power intermittently. This will cause your AC system to turn on and off when your thermostat loses battery power. To fix this try replacing the batteries and restarting the thermostat.

If the above solutions don’t resolve the issue, then the problem could be the thermostat itself. You may want to call a HVAC technician to diagnose the thermostat. E4 error message will be displayed if the thermostat has an internal memory failure. If E4 appears, replace the thermostat.

To remove the indoor thermostat for your Carrier RV air conditioner, do the following:

  • Remove ceiling grille.
  • Remove 5 screws securing the control assembly to the control box cover.
  • Remove the indoor thermostat knob by grabbing the outside edge of the knob and pulling it off of the thermostat stem.
  • Remove 2 screws that secure the indoor thermostat to the lower control box cover.
  • Carefully disconnect the 2 wires from the indoor thermostat.
  • Remove the sensing bulb from the plastic clip.
  • Carefully slide the sensing bulb through the rubber grommet.
  • Remove the thermostat from the control assembly.
  • Reverse above procedure for reassembly.

Connection issues

 If there is a loose or burnt connection, it will arc and turn hot, which may cause the on and off problem. Such a connection transmits enough power to run the fan but not enough to power up the compressor. The whole system shuts off whenever the compressor comes on.

This problem needs to be addressed as soon as possible because it poses the risk of damaging the system components or a fire hazard.

Frozen AC Evaporator Coils

 If the on and off cycle occurs mostly at nights or on humid days, it could be because of frozen AC evaporator coils.

There are two ways to unfreeze them: running the system in the ‘Fan Only’ mode or keeping it off until the coils are back to their normal state.

However, these are only temporary solutions. A permanent solution to this freezing problem will be to operate the air conditioner at a higher temperature. Another way is to change the filter and make sure that there is no build-up or dirt in the coils. Follow these steps:

  • Clean the AC filters. Dirty AC filters can reduce the cooling capacity and efficiency of your Air Conditioner.
  • Once the filter is removed on most RV Air Conditioning units you will be able to see the evaporator coils. Hold a flashlight behind the coil to see if all spaces are clear. Both coils may be vacuumed when dry. You may also brush the coils with a stiff brush and then blow them out with compressed air.

Control board failure

A malfunctioning control board can also cause the same symptoms. If you suspect that the control board is the culprit, consult a certified RV technician to diagnose the problem.

If you are a DIY person and you feel up to the task, here is how to remove the main PCB board to test it or for replacement:

  • Remove ceiling grill.
  • Remove three screws securing the PCB cover to the ducted ceiling unit.
  • Carefully turn over the PCB cover exposing the PCB main and the PCB display assemblies.
  • Gently push holding clip away from PCB main assembly.
  • Lift PCB main assembly from PCB cover assembly.
  • Unplug display wiring plug.
  • Unplug thermistor/thermostat wiring plug.
  • Unplug power wiring plug.
  • Unplug signal wiring plug.
  • Reverse above procedures for reassembly

How to Install Carrier RV Air Conditioner Thermostat (wall mounted)

Thermostat location

The thermostat should be mounted:

  • Approximately 5 foot (1.5m) from the floor.
  •  Close to or in a frequently used room, preferably on an inside partitioning wall.
  •  On a section of wall without pipes or duct work.

The thermostat should NOT be mounted:

  • Close to a window, or an outside wall, or next to a door leading to the outside.
  •  Exposed to direct light and heat from a lamp, sun, fireplace, or other temperature-radiating object which may cause a false reading.
  • Close to or in direct airflow from supply registers and return-air grilles.
  • In areas with poor air circulation, such as behind a door.

To install the thermostat- 12 VDC, follow these steps:

  1. Turn off all power to unit.
  2. If an existing thermostat is being replaced:
  3. Remove existing thermostat from wall.
  4. Disconnect wires from existing thermostat, one at a time. Be careful not to allow wires to fall back into the wall.
  5. As each wire is disconnected, record wire color and terminal marking.
  6. Discard or recycle old thermostat.
  • Separate the front and back pieces of plastic.
  •  Route thermostat wires through the hole in the back piece of plastic. Level plastic against wall (for aesthetic value only – thermostat need not be leveled for proper operation) and mark wall through 2 mounting holes.
  • Drill two 3/16 inch mounting holes in wall where marked.
  • Secure back plastic to wall with 2 anchors and screws provided, ensuring all wires extend through hole in plastic.
  • Connect the wires to proper terminal of the connector block in the front piece of plastic.
  • Push any excess wire back into wall. Excess wire inside the thermostat plastic case can interfere with proper air flow across the temperature sensor. Seal hole in wall to prevent air leaks. Leaks can effect operation.
  • Snap the front and back pieces of plastic together.
  • Turn on power to the unit.

How to Clean and Maintain My Carrier RV Air Conditioner

Regular cleaning and maintenance will help keep your Carrier RV air conditioner in good condition, working effectively, and lasting longer.

There are several maintenance procedures you can perform from time to time:

  1. Painting-Paint any parts that show evidence of rust with a good rust-prevention paint.
  2. Wiring- Check all wiring for deterioration and all electrical contacts for tightness or corrosion.
  3. Mounting-Make sure unit is secure on roof according to installation instructions provided in Owner’s Guide. Check fans to insure that they are correctly positioned in the center of the orifice, and tight on the shaft.
  4. Leaks-Check any connections that show evidence of oil or leaks. When unit is properly installed (refer to Owner’s Guide) check gaskets for possible air leakage.
  5. Controls-Check the unit to ensure all the controls are functioning correctly and unit operation is normal. Vibrations can cause unwanted noise.

Clean the evaporator coil and condenser coil. Hold flashlight behind coil to see if all spaces are clear. Dust accumulation obstructs or reduces airflow and results in loss of cooling capacity. Both coils may be vacuumed when dry. You may also brush the coils with a stiff brush and then blow them out with compressed air.

Clean the base pan, motors, fan wheels, and other components thoroughly. Clean cover and ceiling grill. Mild detergents reduce electrostatic charges on plastic sections of the grill and are good cleaners.

Do not use carbon tetrachloride, solvents, or waxes containing solvents to clean plastic sections.

Check this too: Coleman RV Air Conditioner How to & Troubleshooting Guide

How to Replace a Carrier RV Air Conditioner Filter

For ceiling units (Ducted systems and Free Blow systems)the filters are located in the ceiling grill. To remove the filters, do the following:

  1. Grasp the edge of the filter at recess in the end of the ceiling grill.
  2. Pull filter completely out of the filter slot.
  3. Vacuum filter or wash filter in lukewarm water. Shake off excess water and dry thoroughly.
  4. Replace filter by sliding the filter into the filter slot in the ceiling grill until the filter frame is flush with the interior grill.

Oscar

In his spare time, Oscar loves tinkering with electronics. Solar panels, wiring, old TVs and sometimes DIY powerwalls. When he is not busy trying not to electrocute himself, you can find him in the garden tending to his vegetables and chickens.

Recent Posts