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REFRIGERATION INSTRUCTIONS

 

CAUTION: CAREFULLY READ INSTRUCTIONS BEFORE EVEN PLACING A PRESSURE GAUGE ON THE SYSTEM

 

INTRODUCTION

These refrigeration instructions follow factory practices used in the production of VT-300 CO₂ Satellite Reservoirs.

Before suspecting that the refrigeration system is at fault, several quick evaluations can be made.

1.  Check to make sure that the pressure controller on the compressor is still set to the factory settings of 25psig cut-in and 20psig differential. If the controller has been set to any values other than these, restore the controller to these settings and allow the Satellite Reservoir to run for a few hours before proceeding.

2.  Check the CO₂ liquid outlet or distribution line for any frost or ice-balls being formed.

3.  Check to be sure that the proper CO₂ pressure is being supplied to the satellite. A pressure gauge put on the CO₂ line at the satellite reservoir should read 300 psig. Note that a pressure gauge at the CO₂ supply tank is not sufficient for this test.

4.  While the refrigeration system is running, the compressor discharge line should be hot and the suction line should be cool and may even have a small amount of condensate on the valve.

 

If any of the above conditions are present, do not proceed any further, the satellite is probably operating correctly. Please call Va-Tran Systems for additional assistance with troubleshooting.

A room temperature VT-300 CO₂ Satellite under normal conditions can pull down a 300psig charge of 70^o F CO₂ vapor approximately 30psi in each 15 minutes of operation. The standard factory test given to all VT-300 CO₂ Satellite Reservoirs checks CO₂ pressures every 15 minutes for one hour. Typical data is listed below.

Perform the CO₂ Rate Test as follows:

1.  Unplug the Satellite Reservoir

2.  Ensure that all liquid CO₂ is removed from the Satellite Reservoir by opening a valve on the liquid distribution line. If any liquid CO₂ is present there may not be a fault with the refrigeration system. Refer to the instructions at the beginning of this section before proceeding or call Va-Tran Systems for additional troubleshooting support.

3.  Fill the Satellite Reservoir with CO₂ vapor at 300psig. (Do not fill the Satellite with Liquid CO₂)

4.  Reset the refrigeration controller to 0psig cut-in (there is no need to readjust the pressure controller differential setting). Alternatively, the pressure controller's contacts can be jumpered to allow the compressor to run constantly.

5.  Close the inlet valve to the reservoir and attach a pressure gauge to the Satellite CO₂ system to allow pressure readings to be taken while the satellite is running.

6.  Record an initial pressure reading as well as an initial reading of the ambient temperature in the area of the satellite.

7.  Apply power to the satellite and record the satellite CO₂ pressure every 15 minutes for 1 hour.

8.  Compare the results of your tests with the expected results recorded in the table.

9.  Remove power from the Satellite Reservoir

10.  Reset the controller to factory settings (25 cut-in, 20 differential), or remove the jumper installed onto the controller in step 4.

11.  Open the CO₂ Vapor Inlet valve to allow the Satellite Reservoir to be connected to the supply of CO₂ vapor.

12.  If the results that you obtain compare favorably with the results in the table, There is not a problem with the satellite reservoir that requires refrigeration service.

 

NOTE: Before proceeding further, check to ensure that the refrigeration condenser is free of dirt, dust, and lint. Any accumulation of dust on the fins of the refrigeration condenser will dramatically affect the performance and lifetime of the Satellite Reservoir.

The following test equipment is required to adequately service the VT-300 CO₂ Satellite refrigeration system.

Use a gauge manifold and a source of R-502 to measure the pressure of the high and low sides. Before opening the system's refrigeration valves to the gauges, purge the lines with liquid R-502 by cracking (loosening slightly) the fitting at the system valve end of each of the hoses and allow R-502 to leak for a few seconds.

Under normal operation, the evaporator pressure is about 20psig. The pressure control on the compressor is factory set to 20psi differential (left hand scale) and 25psig cut-in (right hand scale).

The high side pressures of the VT-300 CO₂ Satellite refrigeration systems run about 180 to 200psig depending on the ambient temperature.

The system should be carefully leak checked prior to recharging. The polyurethane foam insulation on the reservoir has a halocarbon blowing agent that will trigger a halogen leak detector, especially if a piece of the insulation is scratched or broken. When checking for refrigerant leaks near the insulation, the leak detector should be shielded from the insulation by a plastic sheet.

If a leak is found, it is advisable to completely recharge the system using a procedure similar to the factory procedure described under CHARGING INSTRUCTIONS. The dryer should be replaced before recharging the system.

Use the following procedure to charge the VT-300 refrigeration system. The compressor is OFF in all steps below.

Time in minutes	Procedure
0	Evacuate system from high side only.
30	Put heat lamp on dryer, open low side valve, continue evacuation.
90	Remove heat lamp, continue evacuation.
120	Break vacuum with R-502 or R-22 to 2psig.
150	Evacuate system from high and low sides.
210	Charge system (see note 1) through low side with liquid refrigerant. Close access valves and remove gauges from system.
240 (see note 2)	Apply power to the Satellite reservoir.

NOTE 1: Refer to unit nameplate for correct refrigerant and charge.

NOTE 2: Allow the Satellite to sit for 30 minutes after charging prior to applying power.

 

677 ANITA STREET, SUITE A, CHULA VISTA, CALIFORNIA 91911
phone: 619/423-4555 toll free 800/379-4231 fax: 619/423-4604

Copyright 1998, Va-Tran Systems Incorporated.

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