Goodman Mfg RT6100004R13 manual S-122REVERSING VALVE REPLACEMENT, Servicing, System Charging

SERVICING

3.An oil trap is required at the evaporator only if the condenser is above the evaporator. Preformed oil traps are available at most HVAC supply houses, or oil traps may be created by brazing tubing elbows together (see diagram below). Remember to add the equivalent length from oil traps to the equivalent length calculation of the suction line. For example, if you construct an oil trap using two 45° elbows, one short and one long 90° elbow in a ¾” diameter suction line, the additional equivalent length would be 0.7+ 0.7+1.7+1.5, which equals 4.6 feet (refer to table 9).

Oil Trap Construction

Long Radius Street Ell

45 °

Ell

45°

Street

Ell

Short Radius

Street Ell

Fig 7. Oil Trap

4.Low voltage wiring. Verify low voltage wiring size is adequate for the length used since it will be increased in a long line application.

System Charging

R22 condensers are factory charged for 15 feet of line set. To calculate the amount of extra refrigerant (in ounces) needed for a line set over 15 feet, multiply the additional length of line set by 0.6 ounces. Note for the formula below, the linear feet of line set is the actual length of liquid line (or suction line, since both should be equal) used, not the equivalent length calculated for the suction line.

Extra refrigerant needed =

(Linear feet of line set – 15 ft) x X oz/ft.

Where X = 0.6 for 3/8" liquid tubing

Remember, for condensers with a liquid valve connection less than 3/8" diameter, 3/8" liquid tubing is required for a line set longer than 25 feet.

Follow the charging procedures in the outdoor unit I/O manual to ensure proper superheat and sub-cooling levels, especially on a system with a TXV installed in the indoor unit. Heat pumps should be checked in both heating and cooling mode for proper charge level. This guideline is meant to provide installation instructions based on most common long line set applications. Installation variables may affect system opera- tion.

NO ADDITIONAL COMPRESSOR OIL IS NEEDED FOR

LONG LINE SET APPLICATIONS

ON RESIDENTIAL SPLIT SYSTEMS.

S-122 REVERSING VALVE REPLACEMENT

Remove the refrigerant charge from the system.

When brazing a reversing valve into the system, it is of extreme importance that the temperature of the valve does not exceed 250° F. at any time.

Wrap the reversing valve with a large rag saturated with water. "Re-wet" the rag and thoroughly cool the valve after each brazing operation of the four joints involved. The wet rag around the reversing valve will eliminate conducting of heat to the valve body when brazing the line connection.

The use of a wet rag sometimes can be a nuisance. There are commercial grades of heat absorbing paste that may be substituted.

After the valve has been installed leak test, evacuate and recharge.

S-202 DUCT STATIC PRESSURES AND/OR STATIC PRESSURE DROP ACROSS COILS

This minimum and maximum allowable duct static pressure for the indoor sections are found in the specifications section.

Tables are also provided for each coil, listing quantity of air (CFM) versus static pressure drop across the coil.

Too great an external static pressure will result in insufficient air that can cause icing of the coil. Too much air can cause poor humidity control and condensate to be pulled off the evaporator coil causing condensate leakage. Too much air can also cause motor overloading and in many cases this constitutes a poorly designed system.

59