A helper suggests filling an empty recovery cylinder with dry nitrogen from the shop bottle so it can be carried to jobs as a portable supply of test gas. What is wrong with that idea?
Correct Answer
A) A recovery cylinder is rated for refrigerant service, not for a high pressure nitrogen fill
A recovery cylinder is a pressure vessel built and stamped for a particular service pressure, commonly four hundred pounds per square inch. A nitrogen cylinder leaves the gas supplier at a couple of thousand pounds. Transferring from one to the other means either an unregulated fill that can burst the recovery cylinder, or a partial fill that gives so little usable nitrogen it defeats the purpose. Cylinders are filled by the gas supplier for the service they are marked for, and a recovery cylinder is marked for refrigerant.
Why This Is the Correct Answer
The service pressure stamped on a recovery cylinder is the limit it was designed and tested to. Nitrogen is stored and supplied at pressures many times higher, so filling a refrigerant cylinder from a nitrogen bottle is either dangerous or pointless depending on how it is done. Cylinders are filled by suppliers for the gas and the service they are marked for, and mixing services is never a field operation.
Why the Other Options Are Wrong
Option B: A recovery cylinder would work but has to be relabelled before the nitrogen goes into it
Labelling addresses what a cylinder contains. It does nothing about a pressure rating, which is fixed by how the vessel was built.
Option C: A recovery cylinder cannot hold nitrogen because its valve passes only liquid refrigerant
Cylinder valves handle gas or liquid according to the dip tube arrangement, and this is not what makes the idea unsafe.
Option D: A recovery cylinder must be evacuated first, after which the transfer is acceptable
Evacuating deals with contamination. The objection here is the pressure rating, which evacuation does not change in any way.
Memory Technique
The stamp on the collar is not a suggestion.
Reference Hint
Cylinders are used only for the gas and service pressure they are marked for. Recovery cylinders hold recovered refrigerant, nothing else.
More epa-608-type-1 Questions
An under-counter ice maker is one factory-sealed cabinet, while a modular ice machine head is joined to a remote condenser by field-run tubing. What certification does servicing the modular machine's circuit require?
A technician recovers refrigerant from a small appliance using a recovery machine that was manufactured in 1991. What recovery level must that older equipment achieve?
Two technicians recover from identical refrigerators with working compressors, one using a 1991 recovery machine and the other a 2015 machine. Why do their required recovery levels differ?
System-dependent recovery equipment may be used only on appliances that normally hold up to what amount of refrigerant?
What feature defines a self-contained recovery unit and sets it apart from the system-dependent kind?
When system-dependent recovery equipment is used on a small appliance whose compressor still runs, how can that working compressor be put to use?
Recovery from a small appliance has slowed down and the pressure is barely moving. What accepted technique helps drive the remaining refrigerant out?
After the recovery unit stops pulling on a small appliance, how does a technician confirm that the recovery is actually complete?
A sealed small appliance offers no service port at all. What has to happen before recovery equipment can be connected to it?
As refrigerant from a string of small appliances collects in a recovery cylinder, what fill limit applies to that cylinder?
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