Carrier 38AKS014-024, 30GT015-035 Install Control Wiring See Fig, Accessory Operation Adjustment

Step 2 — Install Control Wiring (See Fig. 5)

1.Install a field-supplied relay with a 24-v coil and normal- ly closed contacts rated for 20 va at 125 vac inductive load. Mount this relay in the 38AKS control box.

NOTE: This relay is identified in Fig. 5 as HGR (hot gas relay).

2.For 38AKS014-024:

a.Connect a field-supplied wire between TB2-3 and the L1 side of the HGR coil.

b.Connect a field-supplied wire between TB2-9 and the L2 side of the HGR coil.

c.Connect a field-supplied wire between TB2-2 and HGR-4, one of the normally closed (NC) contacts.

d.Connect one leg of the hot gas pilot solenoid valve to HGR-6, the other NC contact.

e.Connect the other leg of the hot gas pilot solenoid valve to C2.

Step 3 — Restore Refrigerant Charge — Charge unit in accordance with 38AKS Charging Chart found on unit.

	TC2	TB2		TB2
		3	LLS	9
			HGR
	TB2
		BLU		C2
		HGR		Hot Gas
		YEL
		LEGEND		Pilot Solenoid Valve
HGR	—	Hot Gas Relay
LLS	—	Liquid Line Solenoid
TB	—	Terminal Block
TC	—	Thermostat Cooling

NOTE: Hot Gas Relay (HGR) use Part No. HN61KK324.

Fig. 5 — 38AKS014-024 Hot Gas Bypass Wiring

ACCESSORY OPERATION AND

ADJUSTMENT

Adjustment — The hot gas bypass valve is set to begin opening when the suction pressure falls to approximately 62 psig (427 kPa). The pressure corresponds to a chilled water set point of approximately 44 F (6 C). If the chilled water set point is lower than 44 F (6 C), the bypass setting must be de- creased. The opposite is true if the chilled water setting is above 44 F (6 C).

Condensing temperature also affects the setting of the bypass valve, and a change may be required. To adjust the setting of the bypass valve, a 5/16 in. hex wrench is required. Remove the cap on the valve, and turn the adjustment nut with the hex wrench. Turning in a clockwise direction increases the setting, and turn- ing in a counterclockwise direction decreases the setting.

Operation — The hot gas bypass accessory operates as fol- lows: When a call for cooling is received, the compressor start circuit is energized, along with the hot gas solenoid (HGS) and all unloaders. Once the HGS circuit is completed, the solenoid valve opens allowing the hot gas bypass valve (HGBV) to sense suction pressure and respond accordingly.

If the suction pressure is below the HGBP (hot gas bypass) valve setting, the valve begins to open. The valve continues to open until it either reaches an equilibrium or the maximum open position. Discharge gas is bypassed into the mixed-phase line between the expansion valve and the cooler. This condition continues until the suction pressure rises above the HGBP valve setting, a second stage of temperature control is called for, or the unit cycles off.

TROUBLESHOOTING

PROBLEM		PROBABLE CAUSE		SOLUTION
Hot Gas Bypass Valve Fails to Open.	1. Dirt or foreign material in valve.		1.	Disassemble and clean valve.
	2.	Equalizer passageway clogged.	2.	Disassemble and clean valve.
	3.	External equalizer not connected or	3.	Connect or replace equalizer line.
		equalizer line is pinched shut.		Check solenoid valve.
Hot Gas Bypass Valve Fails to Close.	1. Dirt or foreign material in valve.		1.	Disassemble and clean valve.
	2.	Diaphragm failure.	2.	Replace element only.

Copyright 2005 Carrier Corporation

Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.

Book	1	2	4	PC 111	Catalog No. 533-00067	Printed in U.S.A.	Form 30GT/38AKS-1SI	Pg 4	1-05	Replaces: 30GT-35SI
Tab	3a	5c	2a