York Y32, Y33, Y34 manual Selection Procedure, Refrigerant Charge, Select Unit

246653-YTG-E-0108

TABLE 2: REFRIGERANT CHARGE

UNIT (TONS)	MODEL	TYPE	FACTORY/ FIELD		CHARGE
			CHARGED	SYS #1	SYS #2	SYS #3	SYS #4
25	wo/HGBP	R22	Factory	25 lb. / 8 oz.	26lb / 0oz	-	-
25	w/HGBP	R22	Factory	26 lb. / 0 oz.	26 lb. / 0oz	-	-
30	wo/HGBP	R22	Factory	13 lb. / 4 oz.	13 lb. / 8 oz.	13 lb. / 8 oz.	-
30	wo/HGBP1	R22	Factory	14 lb. / 6 oz.	14 lb. / 10 oz.	14 lb. / 10 oz.	-
30	w/HGBP	R22	Factory	14 lb. / 0 oz.	13 lb. / 8 oz.	13 lb. / 8 oz.	-
30	w/HGBP1	R22	Factory	15 lb. / 2 oz.	14 lb. / 10 oz.	14 lb. / 10 oz.	-
40	wo/HGBP	R22	Factory	15 lb. / 5 oz.	15 lb. / 4 oz.	15 lb. / 5 oz.	15 lb. / 15 oz.
40	w/HGBP	R22	Factory	15 lb. / 13 oz.	15 lb. / 4 oz.	15 lb. / 5 oz.	15 lb. / 15 oz.

1.With high capacity evaporator coil.

SELECTION PROCEDURE

GIVEN:
Required Cooling Capacity	460,000 Btuh
Required Sensible Cooling	390,000 Btuh
Required Heating (Gas)	320,000 Btuh
Entering Air on Evaporator	83° F DB/ 67° F WB
Outside Design Temperature	95° F
Supply Fan CFM	13,000 CFM
External Static Pressure	1.25 IWG
Electrical Supply Voltage	460-3-60
Economizer Required
2” Throw Away Filters
Constant Volume

SELECT UNIT:

1.Determine nominal tons:

460,000 / 12,000 = 38.33 Tons

Thus, a nominal 40 ton unit is selected.

2.Reference Cooling Capacity Table for a 40 ton unit with standard evaporator coil.

a.Locate the table for a standard evaporator coil with 95° F air on the condenser.

b.Enter table at 13,000 CFM and 67°F WB air on evaporator

c.Trace to 83° F Entering Dry Bulb column.

d.Read 493 MBH total capacity and 403 MBH sensi- ble capacity.

The 40 ton unit will meet the cooling requirements. From the nomenclature, the unit will be a Y34. Choose the appropriate configuration for the next digit. Assuming bottom return and supply, the fourth digit would be an “A,” making the model Y34A.

3.Find Gas Heating Capacity Table.

a.Trace down Output column.

b.Find output which exceeds 320,000 Btuh require- ment. The N5 option gives 426 MBH output.

c.Ensure that it is offered in the Y34 unit. Read option model as N5.

From the basic nomenclature, the model now becomes Y34AN5. Add voltage code of “4” for 460-3-60. Nomen- clature becomes Y34AN54.

SELECT FAN SPEED AND HORSEPOWER REQUIREMENTS OF SUPPLY AIR FAN

1.Find Supply Air Performance Tables for the 40 ton unit.

a.Check footnotes and make necessary additions or deductions to static resistance of ductwork:

Ductwork static resistance	1.25	IWG
Economizer static resistance addition
(interpolate) =.25 IWG + Gas Heat (High) =	0.5	IWG
Total Static Resistance	2.0	IWG

b.Enter Fan Performance Table at 13,000 CFM and

2.0 IWG static pressure:

RPM = 690

BHP = 10.7

NOTE: Either a Class I or Class II blower could be used.

c.Enter the Fan Motor Drive Tables. Selecting a 15 hp motor allows (service factor of 1.5) for a maximum operating BHP greater than the 10.7 BHP require- ment.

SIZE OVERCURRENT PROTECTION DEVICE AND DETERMINE CIRCUIT AMPACITY

1.Find electrical tables for the basic 40 ton unit.

a.Enter table for 460-3-60 voltage.

b.Find 15 hp in the Supply Air Fan column.

c.Trace to Minimum Circuit Ampacity column - read 104.

d.Trace to Max. Fuse/Breaker Size column - read 110.

e.Size wire and overprotection device accordingly.

f.Check all footnotes.

Johnson Controls Unitary Products 11