EPA Type 3 Chapter 6
Major and Minor Repairs
In this module, we will learn about EPA’s classification of major and minor repairs. Skip to quiz!
Major Repairs
EPA defines major repairs as “Maintenance, service, or repair that involves removal of the appliances"
Condenser
Evaporator
Auxiliary heat exchanger coil or
Compressor”
Apart from these, any other repairs are considered as “minor repairs.”
An evaporator or condenser coils are removed/replaced if there is an irreparable flaw in it. Examples of an irreparable flaw would be if the coils have rusted or a hole in the coil piping is so big that it cannot be closed by repairing it.
Evaporator and condenser coils are types of heat exchangers. An auxiliary heat exchanger means a secondary or an extra heat exchanger in the system. It is generally seen in heat pumps and large systems cooling vast spaces.
Examples of major compressor repairs are
A compressor burnout, causing its replacement.
A non-working compressor due to mechanical problems.
A broken or leaking compressor.
We will talk about compressor burnout in more detail.
A compressor burnout is a major repair, and an oil sample is taken to detect it. A sample of the oil is taken to check its properties whenever there is a compressor burnout. A compressor burnout means that the compressor's motor windings have burnt due to a short circuit.
A short circuit in the electrical component produces very high voltage and temperatures. This burns the refrigerant oil during burnout. Burnt refrigerant oil has acidic properties that harm the system.
While repairing any system, a technician should follow these steps,
Isolating the component.
Evacuate the isolated section.
Wait for a few minutes to see if the pressure rises in the system.
Recall that all this has been discussed in the evacuation topic.
Minor Repairs
Apart from all the repairs mentioned above, any other repairs are considered minor repairs. For any such repairs, we generally use the method of heating the system using heating blankets to detect leaks. All repairs are done after detecting leaks and recovering refrigerant if needed.
In this module, we understood EPAs classification of major and minor repairs. This classification of major repairs is an important part of the EPA Type 3 Course.
Safety
In this module, we will learn about a few safety practices that need to be kept in mind while dealing with EPA Type-3 appliances. Skip to quiz!
Basic Safety Precautions
Always remember that whenever working with refrigerants, always make sure that you are wearing proper personal protective equipment (PPE), including
Safety glasses
Safety gloves
Safety shoes
Safety hat/helmet
ASHRAE Standard 15
ASHRAE Standard 15 talks about the safety of persons and property on or near the premises where refrigeration facilities are located. For us, the important part to understand in this standard is the ‘Equipment Room Requirements.’
Recall that refrigerants are toxic, and inhaling them is life-threatening. When refrigeration equipment is kept indoors, a separate room is required for them. Any equipment room must have electronic refrigerant detectors and a mechanical ventilation system running
These systems pull the outside fresh air into the equipment room from one side and exhaust the room air from the other using mechanical fans and blowers. Compare this to a kitchen exhaust fan but much larger in size.
Equipment room refrigerant detectors are electronic detectors that sense refrigerants in the air and give out an alarm. Along with the alarm, the ventilation systems also turn on and start blowing in fresh air into the room. Any traces of refrigerant outside the system indicates a refrigerant leak.
Equipment room refrigerant detectors are also referred to as room sensors in the EPA exam. These sensors are compulsory in all equipment rooms having Type 3 appliances regardless of the refrigerant type.
The alarm will sound just before the TLV-TWA (Threshold Limit Value – Time Weighted Average) is crossed. Any refrigerant amount detected in the air above the TLV of the detector is harmful and sets off the alarm.
TWA is the average refrigerant limit for a normal 8-hour workday and a 40-hour workweek to which any person may be exposed every day without harmful effects. Throughout the day and week, the average refrigerant leak should not exceed the TWA values.
Best Practices
Recall that sight glass is a transparent glass used to check for signs of moisture inside a system. Ice or dirt may form on this sight glass at low temperatures that should be cleaned using an isopropyl alcohol spray. Isopropyl alcohol is also commonly used to de-ice car windshields during winters.
Recall that a ruptured disc is a safety device set to burst open at a pressure of 15 psig. The discharge from the rupture disc should be vented outdoors in the atmosphere. This is done to prevent the accumulation of refrigerant in the equipment room in case of accidents.
Pressure Relief Valve
Recall that a relief valve protects against high pressures in the system. A daily example of this might be the 'Pressure cooker' and how the cap on top of the cooker lifts to release the pressurized steam inside it.
Boilers and compressor systems in the past have reported blasts due to pressures exceeding the allowable pressure for the system. A pressure relief valve is by far the most important safety component. A pressure relief valve must protect every refrigerating system.
Multiple pressure relief valves should never be installed in series to the system lines. This is because installing multiple valves makes all other valves useless as all pressure is released out of a single valve. Also, it may result in excessive loss of the fluid due to multiple valves releasing pressure at the same time.
In this module, we discussed the safety practices that need to be kept in mind while dealing with EPA Type-3 appliances. These practices are critical while performing any repair and maintenance works in any system.
Question #1: A "major repair" under EPA's regulations would be;
Replacing a condenser coil.
Replacing a filter-drier.
Replacing a condenser fan motor.
Replacing a blower fan motor.
Scroll down for the answer...
Answer: Replacing a condenser coil.
EPA defines major repairs as “Maintenance, service, or repair that involves removal of the appliance
Condenser
Evaporator
Auxiliary heat exchanger coil or
Compressor”
By this definition, replacing a condenser coil is a “major repair.”
Question #2: We would take an ____ if a unit has a compressor burnout, and it is considered a ____.
refrigerant sample; major repair
air sample; minor repair
oil sample; major repair
oil sample; normal repair
Scroll down for the answer...
Answer: oil sample; major repair
A compressor burnout is a major repair, and an oil sample is taken to detect it.
A sample of the oil is taken to check its properties.
Question #3: ASHRAE Standard 15-2013 requires which equipment to detect refrigerant leaks?
Room Sensors
Mechanical Ventilators
Pollution Detectors
Air purifiers with HEPA filters
Scroll down for the answer...
Answer: Room Sensors
As per ASHRAE Standard 15-2013, any equipment room must have electronic refrigerant detectors and a mechanical ventilation system running continuously.
However, to detect a refrigerant leak, electronic refrigerant detectors also known as room sensors are used.
Question #4: ASHRAE Standard 15-2013 requires the use of room sensors and alarms to detect refrigerant leaks of;
A1 refrigerants.
B2 refrigerants.
A2 refrigerants.
all refrigerant safety groups.
Scroll down for the answer...
Answer: all refrigerant safety groups.
ASHRAE Standard 15-2013 requires the use of room sensors and alarms to detect leaks of refrigerant belonging to all safety groups.
Question #5: The purpose of isopropyl alcohol is;
to regulate the pressure while evacuation
to remove air from the filter drier
to remove ice off the sight glass
to vent the refrigerant
Scroll down for the answer...
Answer: to remove ice off the sight glass
Ice forms on the sight glass at low temperatures should be cleaned using an isopropyl alcohol spray.
Question #6: Pressure relief valves should never be installed in;
series.
parallel.
vertically.
horizontally.
Scroll down for the answer...
Answer: series.
Multiple pressure relief valves should never be installed in series to the system lines.
It may result in excessive loss of the fluid due to multiple valves releasing pressure at the same time.