Bryant R-22 service manual HeatPump Refrigerant-FlowDiagrams, LeakDetector III. BRAZING

	COOLING CYCLE
	REVERSING VALVE
		(ENERGIZED)
	OUTDOOR FAN
INDOOR	INDOOR COIL
FAN
	ACCUMULATOR
	SUCTION SERVICE
	PORT AT SERVICE
	VALVE (CLG CYCLE)	COMP
		STRAINER
STRAINER		OUTDOOR
		COIL
(METERING)	SUCTION	LIQUID LINE
	SERVICE	PRESSURE SWITCH

	PORT
HEAT PUMP	(BYPASSING)
ACCESSORY	LIQUID LINE SERVICE PORT
FILTER DRIER
	AT SERVICE VALVE (CLG CYCLE)
(DUAL FLOW)

A88400

Fig. 42—Heat Pump Refrigerant-Flow Diagrams

CAUTION: Due to the high pressure of nitrogen, it should never be used without a pressure regulator on the tank.

Leaks in a system pressurized with refrigerant can be spotted with a leak detector that detects extremely small refrigerant leaks. This discussion assumes that system is pressurized with either all refrigerant or a mixture of nitrogen and refrigerant.

If system has been operating for some time, make first check for a leak visually. Since refrigerant carries a small quantity of oil, traces of oil at any joint or connection are an indication that refrigerant is leaking at that point.

A simple and inexpensive method of testing for leaks is to use soap bubbles. Any solution of water and soap may be used. Soap solution is applied to all joints and connections in system. A small pinhole leak is located by tracing bubbles in soap solution around leak.

Use electronic leak detector to check for leaks. This unquestion- ably is the most efficient and easiest method for checking leaks. There are various types of electronic leak detectors. Generally speaking, they are all portable, and most are lightweight, consist- ing of a box with several switches and a probe or sniffer. Detector is turned on and probe is passed around all fittings and connections in system. Leak is detected by either a movement of a pointer on detector dial, by a buzzing sound, or a light.

In all instances, when a leak is found, system charge must be bled down and leak repaired before final charging and operation. After leak testing or leak is repaired, evacuate system, and recharge with correct refrigerant charge.

A88401

Fig. 43—Leak Detector

III. BRAZING

When brazing is required in the refrigeration system, certain basics should be followed:

1.Clean joints make the best joints. To clean:

a.Remove all oxidation from surfaces to a shiny finish before brazing.

TABLE 19—24V PIN CONNECTION TROUBLESHOOTING

MODE OF OPERATION	TERMINAL	LOCATION ON	VOLTAGE	VOLTAGE	POSSIBLE SOURCE
18-PIN CONNECTOR	DESIGNATION	CONTROL BOARD	PATH	REQUIRED	OF PROBLEM
All	R-C	2-1	Input	24	Check transformer (secondary)
Low-speed Cooling	Y1,0-C	8,6-1	Input	24	Check thermostat
High-speed Cooling	Y1, Y2, 0-C	8,7,6-1	Input	24	Check thermostat
Low-speed Heating	Y1-C	8-1	Input	24	Check thermostat
	Y1-C	8-1	Input	24	Check thermostat
High-speed Heating
	Y2-C	7-1	Output	24	Outdoor temperature below
					speed; change temperature
	Y1-C	8-1	Input	24	Check thermostat
Defrost
	Y2, W2, 0-C	7,5,6-1	Output	24	Outdoor temperature below 50°F;
					Coil temperature less than 30°F
Second Stage of	Y1, W2-C	7,5-1	Input	24	Check thermostat
Auxiliary Heat	W3, Y2-C	9,8-1	Output	24	Check balance-point setting
Cooling Second-	Y1, Y2, 0-C	8,7,6-1	Input	24	Ambient thermistor failure;
stage Latching					Check second-stage POT

—37—