Bryant 663C ÐDefrost Control, Ðdefrost Control Speed-Up Timing Sequence, Xiv. Check Charge

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Fig. 15ÐDefrost Control

TABLE 3ÐDEFROST CONTROL SPEED-UP

TIMING SEQUENCE

PARAMETER	MINIMUM	MAXIMUM	SPEED-UP
	(MINUTES)	(MINUTES)	(NOMINAL)
30-minute cycle	27	33	7 sec
50-minute cycle	45	55	12 sec
90-minute cycle	81	99	21 sec
10-minute cycle	9	11	2 sec
5 minutes	4.5	5.5	1 sec

XIV. CHECK CHARGE

Factory charge is shown on unit rating plate. To check charge in cooling mode, refer to Cooling Only Procedure. To check charge in heating mode, refer to Heating Check Chart Procedure.

→A. Cooling Only Procedure

NOTE: If subcooling charging conditions are not favorable, charge must be weighed in accordance with unit rating plate ± 0.6 oz/ft of 3/8-in. liquid line above or below 15 ft respectively.

EXAMPLE:

To calculate additional charge required for a 25-ft line set:

25 ft - 15 ft = 10 ft X 0.6 oz/ft = 6 oz of additional charge Units installed with cooling mode TXV require charging with the subcooling method.

1.Operate unit a minimum of 10 minutes before checking charge.

2.Measure liquid service valve pressure by attaching an accurate gage to service port.

3.Measure liquid line temperature by attaching an accurate thermistor type or electronic thermometer to liquid line near outdoor coil.

4.Refer to unit rating plate for required subcooling tempera- ture.

TABLE 4ÐREQUIRED LIQUID-LINE TEMPERATURE (°F)

LIQUID		REQUIRED SUBCOOLING
PRESSURE AT			TEMPERATURE
SERVICE VALVE				(°F)
(PSIG)	5		10		15	20
134	71		66		61	56
141	74		69		64	59
148	77		72		67	62
156	80		75		70	65
163	83		78		73	68
171	86		81		76	71
179	89		84		79	74
187	92		87		82	77
196	95		90		85	80
205	98		93		88	83
214	101		96		91	86
223	104		99		94	89
233	107		102		97	92
243	110		105		100	95
253	113		108		103	98
264	116		111		106	101
274	119		114		109	104
285	122		117		112	107
297	125		120		115	110
309	128		123		118	113
321	131		126		121	116
331	134		129		124	119
346	137		132		127	122
359	140		135		130	125

B. Heating Check Chart Procedure

To check system operation during heating cycle, refer to the Heating Check Chart on outdoor unit. This chart indicates whether a correct relationship exists between system operating pressure and air temperature entering indoor and outdoor units. If pressure and temperature do not match on chart, system refrigerant charge may not be correct. Do not use chart to adjust refrigerant charge.

NOTE: When charging is necessary during heating season, charge must be weighed in accordance with unit rating plate ± 0.6 oz/ft of 3/8-in. liquid line above or below 15 ft respectively.

EXAMPLE:

To calculate additional charge required for a 25-ft line set:

25 ft - 15 ft = 10 ft X 0.6 oz/ft = 6 oz of additional charge

→XV. FINAL CHECKS

IMPORTANT: Before leaving job, be sure to do the following:

1.Securely fasten all panels and covers.

2.Tighten service valve stem caps to 1/12-turn past finger tight.

3.Leave User's Manual with owner. Explain system operation and periodic maintenance requirements outlined in manual.

4.Fill out Dealer Installation Checklist and place in customer file.

5. Refer to Table 4. Find the point where required subcooling		CARE AND MAINTENANCE
temperature intersects measured liquid service valve pres-		For continuing high performance and to minimize possible equip-
sure.
6. To obtain required subcooling temperature at a specific		ment failure, periodic maintenance must		be performed on this
		equipment.
liquid line pressure, add refrigerant if liquid line tempera-
ture is higher than indicated or reclaim refrigerant if		Frequency of maintenance may vary depending upon geographic
temperature is lower. Allow a tolerance of ± 3°F.		areas, such as coastal applications.
© 1997 Bryant Heating & Cooling Systems 7310 W. Morris St. Indianapolis, IN 46231	Ð12Ð	Printed in U.S.A.	663c181	Catalog No. 5366-300