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What is an evaporator?
In domestic HVAC use an evaporator is a set of coiled tubes with fins around it to channel air flow. When the cooling cycle is on, compressed gas enters the evaporator where it expands and becomes cold resulting in the tubes also becoming cold. The air blowing through the fins is chilled and creates the cooling effect. An evaporator is also known as a
. Evaporator problem can affect the functioning of an HVAC system. Experts on JustAnswer have answered a wide variety of questions on evaporator problems.
How do I clean the evaporator on my Rheem model RCBA-3765GG17 air conditioner? I have removed the cover but the A coil only partially slides out
What you are referring to is the RCBA multiplex coil with 3 rows of short A coils. In many cases, these are not easy to clean. If there is not too much dirt, turn off the unit and allow the coils to get completely dry. Using a soft / medium hard brush, gently brush the dirt off. Be careful not to bend the delicate fins. If there is excessive or coagulated dirt, you can use a spray on cleaner that should be available from HVAC supply or hardware stores. Spray the cleaner into the evaporator. Some cleaners can be left on the coils and the condensate will wash it off when you run the system. Others need to be rinsed off. Follow the instruction on the spray. If rinsing is needed, place some old towels under the coil and rinse with clean water. If this does not work, the evaporator will need to be removed for cleaning and getting a technician to do is advisable.
I had my evaporator coil replacement done earlier this year when it started leaking. Now the air conditioner is not working again and I am told that the evaporator coil is blocked. What does this mean and why did it happen?
When a coil is replaced the normal practice is to purge the system with nitrogen to flush out any air and contaminants. The evaporator is then pressurized and placed in a vacuum to check for leaks. If leaks are found, they are repaired and the flushing is done again. This ensures that the coil is clean and free from any material that could with use, block the tube. It could be that the system was not completely flushed at the time it replaced.
What is the best way to thaw a frozen indoor air conditioner evaporator?
Turn the cooling off using the
and let the fan run. This will allow warm air to flow over the evaporator and melt the ice. A common reason for an evaporator to become covered with ice is inadequate air flow over it. Please check the
and if it is dirty or damaged, clean or replace it.
The evaporator on my Lennox air conditioner has a leak. Can it be repaired or is evaporator replacement required? And if evaporator coil replacement is necessary, can you tell me how much it will cost?
The viability of repairing the leak depends on where on the coil it is. It is a very tricky job. Many technicians do not approve of coil repair as even if the repair is done, there may be problems with the condensation not dripping off properly and falling outside the drain pan. As for the cost, indicative prices are: labor – 3 hours; coil - $500 to $700 (without dealer markup); refrigerant – up to $40 per pound (you may need 10 pounds); miscellaneous items - $100. Add to this freight and the technician’s margin. Please note that these are all very approximate figures which may vary considerably.
The evaporator coils on my air conditioner keep freezing up blocking the air flow. I’ve replaced the air filter and cleaned the coils. The fan seems to be okay. What is causing this and what should I do?
If the filter and evaporator are clean and blower working properly, the most likely cause of the evaporator freezing is a low refrigerant level. This can be a complex job and handling the refrigerant requires certification. It would be best to get a technician to locate and repair the leak and refill the refrigerant.
The efficiency of an evaporator can be affected by dirt, physical damage or impurities in the circulating gas which can cause blockages in the tubes. When dealing with evaporator problems, follow the instructions given in the owner’ manual. Evaporator’s are delicate and easily damaged. If the manual does not cover the problem you are facing, getting expert help is advisable.
Recent Evaporator Questions
. I'm having trouble with my Coleman Evcon gas furnace. The manual says the gas val
Hi. I'm having trouble with my Coleman Evcon gas furnace. The manual says the gas valve shuts off, then resets after a brief power failure. I find that I have to MANUALLY turn the power off and back on, to get the furnace to enter the start cycle again. Bad valve?
Technical question. When pulling a vacuum on an R-410a or R-22
Technical question. When pulling a vacuum on an R-410a or R-22 system that has been pumped down such as in repairs where system is opened to atmospheric pressures or in new installations where refrigerant is compressed in the compressor, what is the procedure for pulling a vacuum?
I recently had the outside unit on my heat pump system replaced
I recently had the outside unit on my heat pump system replaced with a Trane 2TWB3024A1000. At the time it was very cold outside (around 35 degrees) and the tech told me to have someone come out in the spring and check the Freon levels in the cooling cycle. I keep my thermostat set at 72 degrees and the unit would heat my home to that point, but the outside unit ran constantly. I called the company that installed the unit, and they wanted to replace the inside unit as well. Before I did that I called a different HVAC company for a second opinion. The first HVAC tech they sent out said that when he checked the refrigerant pressures he found that the system was low on Freon and there was an issue with the txv in the evaporator coil. He said that in heat pump mode the suction line only got to 65 degrees, so the txv needed to be replaced (again the temp was in the mid 30's at the time). He came back several days later and replaced the txv, put the system on a vacuum and released refrigerant into the system. During this visit he also found that the heat strips were not working so he repaired them and verified operation. I had to call the same company to come out again about 10 days later because the system was not sufficiently heating my home. The second Tech they sent out said that the windings were open when he arrived due to liquid returning to the compressor so he cooled it down and the windings closed. He said that he found non-condensables in the system, and I needed to change the reversing valve, line drier, and pulley vacuum and then recharge the system. So I called the HVAC company I had install the unit because it was still under warranty. They sent someone out and their tech said that the unit was over charged with Freon. It had 8 lbs of Freon when it was only supposed to hold 4 lbs. He also found a wire that had not been connected which he said arched at shorted something out (I didn't write it down so I can't remember what part he said). He ended up replacing the outside unit again and I have had no problems since. Now, my question is could the problems the second tech found (open windings, what he assumed were "non condensables", the faulty reversing valve, line drier, and pulley vacuum all have been caused by the system being over charged with Freon?
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