FAQ - Portable ACs and ECUs

This could indicate that the unit is cutting off on high pressure or low pressure. Possible cause for the low pressure switch cutting off could be that the unit is low on refrigerant, a faulty low pressure switch or the ambient temperature is too low. Possible cause for high pressure switch cutting off could be that the condenser coil is dirty and needs to be cleaned, the unit is overcharged or the ambient temperature is extremely high. The high pressure causing the unit to cycle on and off can only occur on portable units since they are equipped with an automatic reset high pressure switch.
NOTE: All environmental control units (ECUs) are equipped with manually resettable high pressure switches.

Upon initial startup of the unit, you will notice some bubbles in the sight glass. Allow the unit settle and operate for at least 10 minutes before inspecting the sight glass for bubbles again. Under normal circumstances, there should be very little bubbling and mostly a clear sight glass. On the high pressure side, however, bubbles simply mean not all the high-pressure refrigerant has condensed. Some of it still is in its gaseous state (vapor). This could indicate that your unit is low on refrigerant charge, or the high side temperature is too high, perhaps as a result of a blocked condenser.

If the unit is connected out of phase you will experience a loud compressor noise and the airflow out of the evaporator supply air will be minimal. Switch any two of the three hot leads to correct this phasing issue. The compressor should become quieter and the air flow out of the supply should be optimal.

There is a couple of factors that can cause your HVAC system to freeze up, most of which will need to be corrected by your technician. Making sure the filter is clean or replaced and making sure the airflow is not restricted are about the only things you can check or handle yourself.
Low refrigerant: In some cases, freezing up is caused by a leak in the refrigerant lines. Weak solder joints, friction from piping rubbing or vibrating against an object, leaking valves or loose fittings can cause leaks. The age of the system and the nature and location of the leak are the determining factors on whether to have the system repaired or replaced.
Dirty evaporator coil: Over time, the evaporator coil will become dirty. When this occurs, the results are similar to those of having a dirty filter. Gradually you will lose airflow, slowly enough that you probably would not realize it until it freezes up or is not cooling adequately. You will need to contact your local service expert to correct the problem.
Defective blower motor or relay: A blower motor not running at the proper speed or not running at all can cause freezing. It can also be intermittent, starting at full speed and slowing down after it heats up. Or a relay could cause it to start one time and not the next. In either case, you will need to contact your local service expert to correct the problem.

The EPA recommends checking your filters every 30 days, and if dirty to change them. The good thing about Air Rover units is that they are equipped with washable metal filters which can be cleaned any time needed and used again on the unit.

Beginning in 2010, federal laws required that R-22 be phased out. R-22 contains chlorine that is harmful for the environment. R-410a is the earth friendly "green" refrigerant that has replaced R-22. Air Rover has been ahead of this environmental curve and has been using R-410a on all of the previous R-22 XL Series portable air conditioners, which have since been renamed XLP Series.

The maximum allowable duct length is 40 feet. If more length is required consult with the Engineering Department at Air Rover.

This information varies depending on the unit design and can be located on the unit’s electrical wiring schematic and the data plate. Simply look for the “MCA” value.

The time delay is approximately 1 minute; this is to prevent compressor, evaporator motor, and condenser motor from starting at the same time, thus minimizing the inrush current.

Circuit overload can happen from lightning strikes, or more commonly loose connections in electrical components. Electrical connections can loosen over years of use. Once this terminal becomes loose, the contact points will get heated up due to improper contact with each other. Most of the time, it will get so hot that it will melt the part where the terminals are loose and, in a worst case scenario, a small fire might start to burn. But the circuit breaker will trip and cut off the electrical supply to protect the unit. Make sure all connections are tight before resetting the breaker. If the problem continues consult a qualified HVAC technician to look at the unit.

Without any low ambient control, the units are rated to run at a minimum ambient temperature of 50°F. However, our units can be manufactured with a low ambient control option that allows them run in ambient conditions of as low as -30°F.

The standard XLP an WCXLP series are rated at 125°F ambient operating temperature, the SL series at 105°F, whereas the UL, RUL, ULV, RULV, ULS and HT series are all rated to run at 150°F.

Constant run units operate by running the compressor at all times but modulating refrigerant flow through the evaporator coil depending on the cooling load needed. If no cooling is needed, flow to the evaporator coil is shut off. The fan will circulate room temperature air rather than cooled air. When cooling is needed, flow is just restored to the evaporator rather than having to start the compressor from rest. Having this technology helps eliminate the spikes in power consumption when the unit is continually started from rest. If these units are running on generator power, that large power spike could stall the generator and shut it down. Constant run technology is quite advantageous when only generator power is available.

All UL series have been designed and tested to perform well in those exact conditions. The RUL series has been tested and certified to MIL-STD-810F for sand and dust, salt fog, rain, vibration and transportation.

Not all units can be run at either frequency. Most units are dedicated for either 50Hz or 60Hz power but not both. Be sure to review the unit electrical specifications to know for sure.

It is possible that the unit is exceeding the pressure limit set for the system. There is a high pressure switch that shuts the unit down after its limit is reached. The unit may have a restriction in the refrigerant piping, most likely at the TEV, and it isn’t allowing proper flow. As the compressor runs, the pressure builds but isn’t relieved due to the restriction. To verify high pressure cut-out, use a pressure gauge on the discharge tube to compare the reading against the high pressure limit stated on the data plate. Be sure to consult a trained technician since there could be other possible reasons for the unit to behave this way.

If the unit is a constant run one, it is designed to circulate room temperature air when no cooling is needed. If the unit is not a constant run unit, there are a variety of causes:
Freezing coil: The evaporator coil may be freezing up. Review the unit piping for significant ice build-up. If ice is found, review the causes above for a freezing unit.
Compressor not running: It is possible the compressor is no longer running. When you open the access panel for the compressor, the compressor should be making noise and vibrating while operating. If it isn’t, check for power to the compressor.
TEV functionality: It is possible that the thermal expansion valve (TEV) is not functioning properly and allowing the refrigerant to superheat excessively. Consult a trained technician to verify that TEV settings are correct, and the sensing bulb is functioning properly.
Discharge by-pass valve: These units use a hot gas discharge by-pass valve to mitigate any evaporator freezing. It is possible that the valve could be stuck open and sending too much hot gas directly to the evaporator. Consult a trained technician to verify the valve needs to be replaced or properly adjusted if applicable.

Air Rover offers several options for ducting the condenser air with the XLP, HT and SL series. Accessories like the WallPak and CeilPak allow the condenser air to be ducted through an opening in the wall or the ceiling. The WCXLP needs no condenser exhaust since it uses water rather than air for the condenser coil. All UL, ULV and ULS series are intended for outdoor use and need no ducting for the condenser air.

All Air Rover units have a trough to capture condensate liquid emanating from the evaporator coil. The trough uses tubing to exhaust the condensate either into a condensate tank or to the unit drain. Verify that the trough does not have debris in the drain causing it to overflow. Check for any leaks in the drain tubing if the trough is not overflowing.

Portable units come standard with a 5-gallon condensate tank. We offer condensate pumps as an upgrade option.

The 24 volts control signal comes from the control transformer located inside the electrical enclosure. The transformer produces the 24 volts which goes up to your thermostat then out to the air conditioning unit. Try to adjust your thermostat to a lower setpoint and see if it will turn air condioning on. Refer to the unit's wiring diagram and locate where the 24VAC and common lines are coming out the thermostat, and measure the voltage to see if you are reading about 24VAC. If so, then trace 24VAC (blue) line to check every safety control component (time delay relay, high and low pressure cutout switches) for proper functioning. If any of the safety switches is not operating properly, the 24VAC control signal will not reach the compressor/condenser fan contactor coil in order to allow contact with high voltage and power air conditioning. However, if all the safety control switches are working, the issue may be at the thermostat level, which needs to be checked.

Unless specified on the unit’s data plate, it is not recommended to run a 60Hz unit off a 50Hz supply power and vice versa. Consult with Air Rover engineering if you are considering running your unit at another frequency than the one for which the unit was designed.

This is an issue that can occur to constant run units. Constant run units include an electronically controlled TEV which opens and closes to modulate the amount of refrigerant flow through the evaporator and allow the matching of the cooling load at hand. Sometimes, however, the electronic TEV can have a faulty condition causing it to remain stuck shut, thus permanently restricting refrigerant flow through the evaporator coil. In such case, the unit is said to be permanently stuck in bypass mode. Check the electronic TEV and the temperature control board (TCB) for proper functioning.

The lack of hot air can be due to the fact that the electric heating coils are off. Resistive electric heaters used in Air Rover units have an automatic cutout switch which monitors the temperature of the heating coils. When there isn’t [enough] air flow across the coils, the temperature will rise very fast, which can cause them to overheat and burn. The auto-limit switch is designed to sense excessive heat and cut off the control signal (24Vac) to the heater sequencer relay, therefore preventing the coils from overheating.

Yes. See your portable air conditioners warranty and environmental control units warranty here.

No.

Yes, Air Rover accepts Discover®, MasterCard®, VISA®, and American Express® credit cards.

No, we do not. An Air Rover support representative is available to answer your call Monday through Thursday between 8:00AM and 4:30PM Central Standard Time (CST) (GMT - 6:00) and Friday between 8:00AM and 3:30PM.

Phone/International: 1-903-877-3430
Fax: 1-903-877-2793
Email: info@airrover.com