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Start Up and Operation
NextGen ZX Start-Up Guide
Before commissioning, ensure that all valves on the condensing unit are fully opened.
For ZXL Condensing Units, Liquid Line MUST be insulated – atleast ½” minimum insulation .
Careful selection of Expansion Valves due to the increased sub cooling effect by the Vapor Injection plate heat exchanger.
SEE page 16 of this manual
Leak Check
The unit has been leak tested and QA approved from the factory. However, due to handling and shipping the entire refrigeration system
must be tested for leaks. Failure to carry out leak test can result to undesirable system performance.
Step-by-step:
1. Open both the liquid and suction service valves.
2. Ensure the solenoid valve is energized and open.
3. Pressurize the system to 300 psig/21 Bar maximum with dry nitrogen.
4. Allow dry nitrogen to reach all parts of the system.
5. Check all joints and components using soap/bubble test or with an electronic leak detector.
6. Wait for atleast an hour to ensure the system is holding the pressure and is found to be leaked-proof, if the system loses any pressure
over the course of 30 minutes to 1 hour, then it is a sure indication that the system is leaking
If leak has been detected somewhere on the system, relief the pressure and repair the leak. For an effective installation, the system must
be leak tight.
System Evacuation
Evacuating a refrigeration system serves two primary objectives: (1) remove noncondensables and (2) remove water vapor or dehydrate
the system.
Air and moisture are detrimental to system operation. The successful long-term operation of the system depends on thoroughly
conditioning them before charging with refrigerant and the losses associated with improper evacuation erodes system efficiency as well
as costly for the installers.
A 2-stage vacuum pump along with a micron gauge is recommended in performing evacuation. The quality of vacuum is not determined
by time – a micron gauge must be used since it is the only device that accurately reads the vacuum pressure during the evacuation
process.
REMINDER:
Do not use the system compressor as a vacuum pump and do not operate the compressor while the system is in vacuum.
Emerson Climate Technologies recommends Triple Evacuation Process (best practice) to be implemented on all our installations.
Step-by-step:
1. Open both the liquid and suction service valves.
2. Ensure the solenoid valve is energized and open.
3. Connect vacuum pump to the liquid and suction service valves.
4. Start the vacuum pump and then open the service valves.
5. Perform triple evacuation process as follows:
i. Vacuum until a pressure of 1,500 microns is reached — at which time the vacuum should be broken with the refrigerant
to be used in the system through a drier until the system pressure rises to 2 psig
ii. Repeat this process again
iii. Evacuate the entire system to 500 microns
At this point, Valve Off the system, turn off vacuum pump then wait 30mins before checking the micron gauge readings:
∙ Between 500 and 1,000 microns – Evacuation is Complete! Proceed with refrigerant charging
∙ Above 1,000 but below 5,000 microns – Moisture was NOT Completely Removed.
TO DO: RE-Evacuate the System until Vacuum will Hold
∙ Above 5,000 microns – Indicates System Leak or within the connections
TO DO: Search for the leak & carry-out repair procedures then perform triple evacuation process again
6. The evacuation process is complete once vacuum quality is achieved. Then close the two manifold valves tightly. Close the pump
main valve, and remove the vacuum pump.
KEEP IN MIND
