EPA 608 Type 2 Chapter 13 (Take full course for free)
In this module, we will learn about a few safety practices that need to be kept in mind while dealing with EPA Type-2 appliances. Skip to quiz!
1. 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
2. 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 continuously.
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.
Recall that refrigerants are heavier than oxygen and settle down at the bottom of the room in case of a leak. However, ammonia (R717) is a lighter refrigerant than air and rises to the top in case it leaks. The leaked R717 will accumulate at the top of the room and won’t be fatal.
For an equipment room having R717 in the systems, a refrigerant detector is not needed. Provided the mechanical ventilation systems are working continuously so that the leaked refrigerant is being thrown out of the room. Recall that ammonia is a natural refrigerant, and there are no prohibitions on its venting.
3. Best Practices
Recall that a filter drier traps air, moisture, and other contaminants from the system's refrigerant. If a system is opened for servicing, repair, and maintenance works, the outside air and dust particles enter the system.
Though evacuation removes the air from the system, it cannot remove the air from the filter drier. This is because a filter drier is meant to trap air, and there is no way to remove it from within the drier. So it is a good practice to replace the filter drier every time a system is opened.
Recall that dry nitrogen is used to check for leaks and to evacuate a system. Dry nitrogen tanks are under high pressure, so the nitrogen cylinders require a pressure regulator to reduce the pressure to a safe level. A pressure regulator is required to maintain the pressure and flow of the nitrogen gas.
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.
4. Compressor Safety Precautions
Recall that a hermetic compressor has all the components in a single shell. The compressor motor, when energized, produces a lot of heat. In this type of compressor system, the refrigerant performs the function of cooling the compressor motor.
As a safety precaution, the hermetic compressor should never be started if the system is under vacuum. Recall that during a deep vacuum, the refrigerant has been completely recovered before starting the evacuation process. The hermetic compressors’ motor winding gets damaged if energized due to overheating.
A reciprocating compressor compresses the refrigerant in a cylinder. A reciprocating compressor is very similar to a car engine.
A reciprocating compressor should never be started when the discharge service valve is closed. If the discharge service is closed, it does not allow the flow of refrigerant out from the compressor. In such situations, the compressed refrigerant will have nowhere to go and will build up high pressure in the compressor and damage it.
5. 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.
6. Conclusion
In this module, we discussed the safety practices that need to be kept in mind while dealing with EPA Type-2 appliances. These practices are critical while performing any repair and maintenance works in any system.
Question #1: An equipment room has an appliance that uses R717. Under ASHRAE Standard 15, which piece of equipment is not compulsory in the room?
Fire extinguisher
Refrigerant Detector
Mechanical ventilation system
Mechanical exhaust fans
Scroll down for the answer...
Refrigerant Detector
For an equipment room having R717 in the systems, a refrigerant detector is not needed.
Question #2: Which of the following should be replaced if a system is opened for servicing?
Filter drier
Thermostat
Metering device
Crankcase heater
Scroll down for the answer...
Filter drier
A filter drier is meant to trap air and moisture, and there is no way to remove it from within the drier.
So it is best to replace the filter drier whenever the system is opened for repairs.
Question #3: 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
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to remove ice off the sight glass
Ice forms on the sight glass at low temperatures that should be cleaned using an isopropyl alcohol spray.
Question #4: When the ____ is closed, the reciprocating compressor might get damaged if it is energized.
discharge service valve
suction service valve
shut-off valve
thermal expansion valve
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discharge service valve
When the discharge service valve is closed, the reciprocating compressor might get damaged if it is energized.
Question #5: Pressure relief valves should never be installed in;
series.
parallel.
vertically.
horizontally.
Scroll down for the answer...
series.
Multiple pressure relief valve 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.