Emerson VSR, VSM, VSS service manual OIL Charge, Vii

Installation

To begin the second evacuation, allow the pump to operate and reduce the pressure again to within 50 to 1000 microns. After this reading is reached, allow the pump to operate 2 or 3 hours. Stop the pump and let the system stand with this vacuum. Again using dry nitrogen, raise the system pressure to zero.

For the third evacuation, follow the previous procedure with the pump operating until system pressure is reduced below the 1000 micron level. Run the pump an additional 6 hours and hold the system for approximately 12 hours at low pres- sure. After this, again break the vacuum with dry nitrogen and allow the pressure in the system to rise slightly above zero pounds (psig). Install new drier cartridges and moisture indicators. Charge the system once more below the 1000 micron level and use the refrigerant designed for the system.

When properly evacuating the system as outlined above, the system is dry, oxygen-free and free of non-condensables. The piping should not be in- sulated before the evacuation process is started. If moisture is in the system before evacuating, it condenses in low places and freezes. If this hap- pens, it can be removed by gently heating the trap farthest away from the vacuum pump. This causes the ice to melt and water to boil. Water va- por collects in the next trap towards the vacuum pump. This process should be repeated until all pockets of water have been boiled off, and the vacuum pump has had a chance to remove all the water vapor from the system.

VI. UNIT OIL CHARGING

The compressor unit is shipped from Vilter with no oil charge. The initial oil charge can be made through the drain valve at the oil receiver/separa- tor. Vilter motor driven and manually operated oil chargers are available for this purpose. Once the unit has been started and is operating above 50% capacity, oil may have to be added to bring the oil level to the normal operating point. With the unit operating, oil should be added through the charging connection at the suction strainer. The normal operating level is between the (2) sight glasses on the oil separator. See Table 2 for approximate oil charge requirements.

TABLE 2.	OIL CHARGE
Oil Separator Size	Approximate Oil
	Charge (Gallons)
VSR 16”	20 to 27
VSR 20”	22 to 31
VSM 20”	20 to 25
VSM 30”	30 to 35
20”	30 to 40
24”	40 to 50
30”	60 to 75
36”	95 to 105
42”	145 to 165

The oil level may be above the top sight glass at this time. Later, when the unit is placed in operation, there will be some drop in the oil level as the various oil lines, oil filter and other piping becomes charged with the normal amount of oil that will be in circulation. This drop in oil level should bring the level in the oil receiver/ separator into the normal operating range. Do not mix oils.

A.Oil For Single Screw Compressors

Due to the need for adequate lubrication, Vilter recommends only the use of Vilter lubricants, designed specifically for Vilter compressors. With the extensive research that has been per- formed, we are able to offer refrigerant specific lubricating oils. Use of oil not specified or sup- plied by Vilter will void the compressor warranty.

Please contact your local Vilter representative or the Home Office for further information.

VII. SYSTEM REFRIGERANT CHARGING

CAUTION

When charging the system, make sure the compressor unit is pressurized from the dis- charge side of the compressor. Pressurizing the compressor from the suction side may cause rotation of the compressor, without oil supply, which could lead to internal damage.

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