What must be on the nitrogen cylinder?
Safety · EPA 608 Type III. The correct answer, and the reasoning behind it.
ASHRAE Standard 15 equipment-room requirements and refrigerant sensors.
The question
A technician will raise an R-113 machine's pressure with nitrogen for a leak test. What must be on the nitrogen cylinder?
- A check valve and nothing else
- A flow meter set to the chiller tonnage
- A pressure regulator, with a relief valve downstreamCorrect answer
- No fittings; open the cylinder valve slowly
Why “A pressure regulator, with a relief valve downstream” is correct
A full nitrogen cylinder holds far more pressure than a low-pressure chiller shell can take. A regulator and relief valve keep the test pressure under control and at or below the 10 psig ceiling, or the manufacturer's lower limit if it gives one.
Source: EPA: Test Topics; Trane CTV-SVX05H-EN, R-123 handling guide (8 psig leak test)
Why the other answers are wrong
- A check valve and nothing else — A check valve does not limit the pressure delivered to the machine.
- A flow meter set to the chiller tonnage — Flow meters do not protect the shell from overpressure.
- No fittings; open the cylinder valve slowly — A nitrogen cylinder holds very high pressure and must never feed a chiller without a regulator.
Practice more of this
More EPA 608 Type III practice questions, or see every EPA 608 practice test.
Unofficial, not affiliated with the EPA or any EPA-approved certifying organization. Questions are original practice written from public EPA material, not real exam questions.