• SkillCat Team

Diagnosing Issues

EPA 608 Type 1 Chapter 10 (Take full course for free)


In this module, we will take a look at maintenance guidelines and some common issues we have to deal with when servicing small appliances. Skip to quiz!


1. Recovery Device Maintenance

Practicing technicians need to regularly check recovery equipment for refrigerant leaks. The earlier we can catch a leak, the easier it is to repair the recovery equipment.


We don’t want to find out mid-recovery that the recovery device is leaking. A leaking recovery device will vent refrigerants into the atmosphere and can also lead to dangerous scenarios with flammable or toxic refrigerant.


To prevent these issues, we as technicians should regularly check our recovery devices for leaks.



2. Leak Repair


For small appliances that are leaking, the EPA does not technically require us to repair the leak. But the EPA recommends to repair it whenever possible.

Financially, it also makes sense for us to repair any leaks we find. Repairing leaks would prolong the life of the equipment and smaller leaks are always easier to fix than big ones.


The requirements for small appliances are not as stringent because the amount of refrigerant is under 5 lbs, by definition. And refrigerants used in household refrigerators, especially new ones, are generally non-toxic.


For example, newer household refrigerators contain about ⅓ lb of hydrocarbon refrigerants, which are non-toxic. This is compared to 50+ lbs of refrigerant in other appliances.


Additionally, if the appliance is still working properly, that means any leak in the appliance is minimal. But if the appliance is not working and we find that the system pressure is 0 psig, this means that there was likely a leak in the system and there is no refrigerant left to recover.


3. Compressor Burnout


A compressor burnout is when the motor of the compressor fails catastrophically. For a sealed system, pungent smell usually indicates compressor burnout.


When a compressor burns out, it produces a highly acidic oil. Most of this oil will remain in the compressor, but some oil will make it to the plumbing and other components of the system.


In the event of a suspected compressor burnout, we should first recover any refrigerant in the system in a separate recovery container. It might be contaminated so we don’t want to use a recovery container used for other refrigerants.


Then, look for signs of contamination in the oil.

Signs of contamination are:

  • Discolored oil, and

  • An acidic smell

If we see these signs of contamination, the system needs to be flushed because oil can be present in other components in the system. Flushing the system will clean any contaminants from other components of the system.


4. Non-Condensables


Non-condensables are gases that do not condense (or turn from vapor to liquid) at the operating temperatures of the system. Examples of non-condensables are water vapor and nitrogen.


The presence of non-condensables in the refrigerant changes the properties of the refrigerant. It makes the system less efficient at cooling and increases the pressure of the system.

If there is a high quantity of non-condensables in the system, this shows up as increased pressure on the high side of an active recovery device. So if you see an abnormally high pressure on the high side of an active recovery device, we know that there is a lot of non-condensables in the refrigerant.


Taking pressure readings allows us to determine whether there are non-condensables present. We can check what the refrigerant’s pressure should be at a given temperature by looking at the refrigerant’s PT chart. If the pressure reading is off by a lot, then we know there are non-condensables present.


To remove non-condensables, we can use:

  • Filter driers. Filter driers are components that use desiccants to trap contaminants, including: acids, wax, and moisture.

  • We can also flush the system to get rid of non-condensables.

5. Conclusion


In this module, we discussed the importance of regularly checking your recovery devices to prevent venting. We also covered leak repair requirements, signs of a compressor burnout, and the effect of non-condensables. Next, we’ll have a look at safety issues.


Question #1: What piece of equipment should we check regularly for leaks?

  1. Recovery device

  2. Recovery vacuum pump

  3. Access fittings

  4. All of these

Scroll down for the answer...












Recovery device

We need to check recovery devices regularly because they have the highest probability of venting refrigerant.

It is not necessary to check vacuum pumps for leaks because they are used after refrigerant is recovered anyway. And vacuum pumps are used to vent non-condensables into the atmosphere, so checking for leaks is unnecessary.

Access fittings need to be leak tested before use, not as part of a regular maintenance routine.


Question #2: Which of the following statements is true for small appliances?

  1. The EPA requires repair of all leaks above 80% of the leak rate

  2. The EPA does not require repair of leaking small appliances

  3. The AHRI Standard 740 requires repair of leaks

  4. You should not repair leaking small appliances

Scroll down for the answer...











The EPA does not require repair of leaking small appliances

The EPA does not require technicians to repair leaks on small appliances, so (b) is correct.

(a) This is not true

(c) This is not what AHRI Standard 740 says

(d) You should repair leaking small appliances because it will prolong the life of the appliance. Small leaks are also easier to fix than big leaks, so technicians should fix leaks whenever they are discovered.


Question #3: When the system pressure is found to be 0 psig, what does this indicate?

  1. There has been a leak

  2. There is minimal refrigerant left in the appliance

  3. We cannot recover refrigerant

  4. All of these

Scroll down for the answer...











All of these

If the system’s pressure is 0 psig, then all of these are true.


Question #4: Which of the following indicates a compressor burnout in a sealed system?

  1. A pungent smell

  2. A pungent, sweet smell

  3. A pungent taste

  4. All of these

Scroll down for the answer...













A pungent smell

A pungent smell usually indicates a compressor burnout.

Under no circumstances should we taste any refrigerant or refrigerant oils.


Question #5: What are signs of contamination?

  1. Discolored oil

  2. Acidic smell

  3. Both (a) and (b)

  4. None of these

Scroll down for the answer...











Both (a) and (b)

Discolored oil and an acidic smell are boths signs of contamination.


Question #6: If the oil is contaminated, what do we have to do?

  1. Flush the system

  2. Flush the compressor

  3. Flush the recovery device

  4. All of these

Scroll down for the answer...











Flush the system

If the oil is contaminated, we need to flush the entire system. Even though the burnout occured in the compressor, the contaminated oil could be present in other components.

If we recharge refrigerant into the system, the remaining contaminants would make their way back into the refrigerant. So we need to flush the whole system if contamination is found.


Question #7: Non-condensables would ____ the pressure on the high side of an active recovery device.

  1. Increase

  2. Decrease

  3. Have no effect

Scroll down for the answer...











Increase

If non-condensables are present, the pressure on the high side of an active recovery device would increase.


Question #8: Which of the following would remove non-condensables from a system?

  1. Filter driers

  2. Flushing the system

  3. Both (a) and (b)

Scroll down for the answer...











Both (a) and (b)

Both filter driers and flushing the system would remove non-condensables from a system.


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