What is the first thing to do when a new system has been assembled (built up), and is ready for testing? Pressurize with an inert gas and leak check. You just studied 25 terms!
When recovery is first started at what phase?
After liquid recovery, the remaining refrigerant is recovered in vapor form. Vapor recovery is slow &, consumes more time. So to save time, the recovery process is started by removing the liquid part first.
Which of the following should be replaced if a system is opened for servicing?
25 Cards in this Set
| Which of the following should be replaced if a system is opened for servicing? | Filter drier |
|---|---|
| How can you speed up the removal of the refrigerant charge from a system? | Cooling the recovery cylinder to lower its pressure. |
What should be done after reaching the required recovery vacuum on an appliance?
What should be done after reaching the required recovery vacuum on an appliance? Wait for at least a few minutes to see if the system pressure rises. You just studied 152 terms!
How long must owners and operators of regulated appliances?
Owners and operators of regulated appliances containing 50 or more pounds of regulated refrigerant should maintain all records for at least 3 years.
What is the first thing to do when a new system has been assembled and is ready for testing?
What is the first thing to do when a new system has been assembled (built up), and is ready for testing? Pressurize with an inert gas and leak check. You just studied 25 terms!
When recovery is the first started at what phase is the refrigerant removed to save recovery time?
The key to a quick recovery procedure is to get the liquid out first, then get the remaining vapor out. There are three different ways to remove refrigerant from the system: push-pull recovery, liquid recovery, and vapor recovery (the most common).
What should be done to reduce refrigerant loss?
How would you SAFELY reduce refrigerant loss from a purge-unit on a low pressure unit? 1) Leak test and repair the chiller. 2) Seal the purge-unit discharge. 3) Plumb the purge-unit discharge back into the low side.
When did hermetic system first inspect?
While inspecting any hermetic system, traces of oil are ideally the first signs a technician should look for. Question #3: Which part of a belt-driven non-hermetic compressor is most likely to leak if the compressor has not been used for several months?
What precaution should be taken prior to recovering refrigerant from a chiller suspected of having tube leaks?
Question #4: What precaution should be taken prior to recovering refrigerant from a chiller suspected of having tube leaks? Drain the watersides of the evaporator and condenser. Run the circulating pumps. Be certain the purge unit is operating.
What should be done before transferring refrigerant?
What should be done before transferring refrigerant to an empty cylinder? The cylinder should be evacuated.
What should be used to remove ice from sight glasses?
Isopropyl alcohol should be used to remove ice from sight glasses or viewing glasses.
When must you connect a hose in order to recover liquid refrigerant?
You need to connect a hose from the low side of the manifold to the high side of the recovery unit. 3. The low-loss hose should be connected to the low-side service port from the discharge side of the recovery unit.
What must an owner of a commercial refrigeration appliance with a charge of 2000?
What must an owner of a commercial refrigeration appliance with a charge of 2000 pounds of r-22 do once the leak rate threshold has been exceeded? a. Take further action by repairing, retiring, mothballing, or retrofitting the appliance.
What conditions allow for a system to be opened and repaired without recovering the refrigerant to the required vacuum level?
What conditions allow for a system to be opened and repaired without recovering the refrigerant to the required vacuum level? A system with a large leak and internal pressure of 0 psig.
When should the refrigerant be removed from the condenser outlet?
Refrigerant should be removed from the condenser outlet if the condenser is below the receiver. In a building that has an air-cooled condenser on the roof and an evaporator on the first floor, recovery should begin from the liquid line entering the evaporator.
What is located after the evaporator?
The component directly following the evaporator of the refrigeration system is the. Accumulator.
What is the best use for testing with soap bubbles?
Soap Test for Gas Leak – Gas Leak Detector Soapy Water
Apply soapy water to the entire hose assembly, including the tank’s valve and regulator, using a spray bottle or sponge. Pressurise the system without turning on any appliances. If you see bubbles or smell rotten eggs, you have a leak.
How would you remove moisture from refrigerant in a system?
Moisture can be removed from a refrigeration system by applying a vacuum. POEs hold moisture more tightly than mineral oil. But in the case of R-134a, the refrigerant effectively competes with the ester lubricant in partitioning the water (i.e., the water moves from the lubricant to the refrigerant).
How do you charge a recovery tank?
R-410A Charging and Recovery Procedure with Digital Test Probes …
How do Recovery machines work?
When a recovery machine is hooked up to the manifold or Schraeder valves on the air conditioning system, it creates a vacuum and sucks all the Freon out of the vehicle, cleanses it through a filter and stores it in a storage tank.
How does a refrigerant recovery tank work?
The push-pull recovery method is used for transferring large volumes of liquid refrigerant. The recovery unit “pulls” vapor from the recovery cylinder and produces high-pressure discharge gas that “pushes” liquid out of the HVAC system and back into the recovery cylinder.
What steps can be taken to prevent air accumulation into an idle low-pressure refrigeration system?
What steps may be taken to prevent air accumulation into an idle low-pressure refrigeration system? Leave the purge unit on at all times. Leave the purge unit on at all times. System pressure should be maintained slightly above atmospheric pressure.
What evacuation level must technicians recovery?
25 Cards in this Set
| Where should the discharge from a rupture disc be piped for venting? | Outdoors |
|---|---|
| What evacuation level must technicians recover refrigerant to before disposing a low-pressure appliance? | 25 mm of Hg absolute |
Why must water be circulated through a chiller?
Why must water be circulated through a chiller during refrigerant evacuation? … To prevent freezing of water in the appliance.
When using recovery equipment manufactured before November 15 1993 you must evacuate a low pressure chiller to what level before making a major repair?
Using evacuation equipment manufactured on or after November 15, 1993, and • The compressor in the appliance is operating. should be evacuated to at least 0 psig before it is opened (if high- or very high-pressure appliance) or be pressurized to 0 psig before opening if it is a low-pressure appliance.
Where is refrigerant added to a centrifugal machine?
Type III
| A | B |
|---|---|
| Evaporator charging valve | Refrigerant is added to a centrifugal machine through which valve? |
| Nitrogen | During evacuation of a system with large amounts of moisture it may be necessary to increase pressure with gas such as what to avoid freezing? |
When should an appliance not be evacuated?
The reference manual states “Appliances do not need to be evacuated all the way to the prescribed level if the appliance is being disposed of”.
How should refrigerant be recovered from a chiller?
HVAC Chiller Refrigerant Recovery Procedure – YouTube
What steps must be taken to prevent air accumulation?
What steps may be taken to prevent air accumulation into an idle low-pressure refrigeration system? Leave the purge unit on-line at all times. Maintain system pressure slightly above atmospheric pressure. Open the air vents on the condenser.
What is the best method to determine a chillers normal charge?
What is the best method to determine a chiller’s normal charge for leak rate calculations? Use the charge stated on the equipment nameplate. Approximately how much refrigerant vapor is left in an average 350-ton R-123 chiller at 0 psig once all the R-123 liquid has been removed?
What is the first thing to do when a new system has been assembled and is ready for testing?
What is the first thing to do when a new system has been assembled (built up), and is ready for testing? Pressurize with an inert gas and leak check. You just studied 25 terms!
What must be done to the refrigerant that is vented off the top when filling a charging cylinder?
When filling a charging cylinder with a regulated refrigerant, The refrigerant vapor that is vented off the top of the cylinder must be recovered. If after installing a fitting for the purpose of recovering the appliances refrigerant, you find that the system pressure is 0 psig, Recovery is not required.
What do you do prior to introducing recovered refrigerant to a motor vehicle?
Before you begin transferring recycled refrigerant into an empty storage cylinder, in order to remove non- condensable gases, the cylinder must be evacuated to at least 27 in. HG of vacuum. Refillable cylinders must be UL or DOT approved and must be hydrostatically tested and date stamped every five years.
How can you speed up the removal of the refrigerant charge from a system?
Removal of the refrigerant charge from a system can be conducted more quickly by, packing the recovery vessel in ice.
What should be done before transferring refrigerant to an empty cylinder?
Before transferring refrigerant into an empty cylinder, it should first be evacuated to remove the non-condensable gases from the refrigerant tank.
…
- The refrigerant should be chilled.
- The refrigerant should be mixed.
- The cylinder should be heated.
- The cylinder should be evacuated.
What should be done before transferring refrigerant to an empty cylinder quizlet?
The motor relies on the flow of refrigerant through the compressor for cooling. What should be done before transferring refrigerant to an empty cylinder? The cylinder should be evacuated.
What may be done to speed the recovery process?
What may be done to speed the recovery process and ensure that all CFC, HCFC, or HFC refrigerant has been removed from a frost-free refrigerator? Turn on the defrost heater to increase the refrigerant’s temperature and vaporize any liquid.
What action must an owner operator?
Owners or operators must take corrective action when an appliance with a full charge of 50 or more pounds is discovered to be leaking ozone depleting refrigerant at a rate that exceeds the applicable trigger rate.
How long must owners and operators of regulated appliances?
Owners and operators of regulated appliances containing 50 or more pounds of regulated refrigerant should maintain all records for at least 3 years.
What precaution should be taken prior to recovering refrigerant from a chiller suspected of having tube leaks?
Question #4: What precaution should be taken prior to recovering refrigerant from a chiller suspected of having tube leaks? Drain the watersides of the evaporator and condenser. Run the circulating pumps. Be certain the purge unit is operating.
When charging an R 410A system that uses a water cooled condenser you must first charge with vapor to a pressure of at least?
77 Cards in this Set
| heat pumps that use R- 410A should be leak check with | pressurized nitrogen |
|---|---|
| When charging an R12 refrigeration system that uses a water-cooled condenser you must first charged with Vapor to a pressure of at least ______before switching to liquid charging | 35 PSIG |
When a unit is opened for servicing the should always be replaced?
#21. When a unit is opened for servicing, the ________ should always be replaced. When a unit is opened for servicing, the filter-drier should always be replaced.
When recovery is first started at what phase is refrigerant removed to save recovery time?
The key to a quick recovery procedure is to get the liquid out first, then get the remaining vapor out. There are three different ways to remove refrigerant from the system: push-pull recovery, liquid recovery, and vapor recovery (the most common).