KeepRite K40-CU-IM-13, Installation And Maintenance Instructions Manual

Page: 21 / 36

21
Line Insulation
After the final system leak test is complete, it is important that all refrigerant lines exposed to high ambient
conditions must be insulated to reduce the heat pick-up and prevent the formation of flash gas in the liquid lines.
Suction lines should be insulated with 3/4 inch wall insulation, Armstrong “Armaflex” or equal. To prevent rupture
due to condensate re-freezing, all suction vibration eliminators on low temperature systems
must be
completely insulated . Liquid lines exposed to high ambient temperatures should be insulated with 1/2 inch wall
insulation or better. Any insulation that is to be located in an outdoor environment should be protected from UV
exposure to prevent deterioration of the insulating value.
Refrigerant Charging
Condensing units must be charged only with the refrigerant for which they were designed. The type of
refrigerant to be used is specified on the name plate of the unit. Installing a liquid line drier between the service
gauge and the liquid service port when charging a unit will ensure the refrigerant supplied to the system is clean
and dry. This is especially important when charging a low temperature system. Blend type refrigerants (400
series, i.e. R404A)
must not be vapor charged unless the cylinder is completely emptied into the system.
Weigh the refrigerant drum before and after charging in order to keep an accurate record of the weight
of refrigerant put into the system.
IMPORTANT REFRIGERANT CHARGING NOTE
Overcharging a system can result in poor system performance, personal injury and / or compressor damage.
DO NOT charge strictly by the holding capacity of the receiver. DO NOT assume that bubbles in a sight glass,
when located at the condensing unit, indicates the system is undercharged.
Note: To estimate the total system requirement, refer to the manufacturer’s evaporator and condensing unit
specifications on typical operating charges and include the amount for the liquid lines (see tables below). Allow
an extra 10% to 15% safety factor. Ensure the receiver can handle the required charge during the pump down
mode. (Refer to the condensing unit brochure pump down specifications).
Break the vacuum by charging liquid refrigerant into the receiver side only (charge through the receiver outlet
valve gauge port with the valve in the open position). Close the valve and then continue to charge through the
gauge port feeding the liquid line and evaporator. Start the compressor and continue to charge.
Refrigerant may be added at the compressor through the compressor suction service valve
in gas form only .
When liquid charging is used, a liquid charging valve must be installed. While charging the system, special
attention should be paid to the oil level in the compressor.
If charging to the “bubble” method (observing liquid line sight glass), always use a sight glass located directly
before the TXV (thermostatic expansion valve) for the final indicator.
On units that use an adjustable flooded condenser pressure-regulating valve (Sporlan ORI-6 or ORI-10) the
proper adjustment must be set. Sporlan set their controls at 120 psig (929 kPa). These controls should be re-
adjusted to the following pressures:
185 psig (1377 kPa) for R-22 (2 1/2 turns in clockwise for ORI-6, 4 turns in for ORI-10)
200 psig (1480 kPa) for R-404A (3 turns in clockwise for ORI-6, 5 turns in for ORI-10)
Refer to Sporlan’s installation instructions (bulletins 90-30-1 and 90-31) for further details.