Carrier 48MA/50ME016-040 specifications Gas Heat Lighting Procedure 48MA, Ð Humidistat Connections

	LEGEND
HA Ð Heat Anticipator		Screw Terminal
HU Ð Humidistat
		Printed Circuit
TC	Ð Thermostat, Cooling
TH	Ð Thermostat, Heating	Factory Control Wires

Field Wiring

Fig. 30 Ð Humidistat Connections

The heating thermostat energizes a 115-v solenoid by means of a gas valve relay and the pilot lights. The main burner comes on after the pilot is proven.

The safety switches (air¯ow switches 1 and 2, pilot ¯ame sensor, door switch, and limit switches) are in series with the gas valve.

Gas Heat Lighting Procedure (48MA)

1.Purge gas supply line of air. Make sure unit main manual and zone module gas valves have been off for 5 minutes before proceeding.

2.Set each zone thermostat to the lowest setting.

3.Turn zone module and main manual gas valves to ON position, and secure door of burner compartment.

4.Turn on unit main power supply. Set control circuit serv- ice switch in condensing control box at ON position. Evapo- rator fan will be energized.

5.Set zone thermostat to call for heat. Pilot will light. The main burner will come on after the pilot is proven.

NOTE: A time-delay relay will shut unit down in 180 sec- onds if main manual gas valve is not open.

TO SHUT OFF GAS HEAT Ð Set control circuit service switch at OFF position. Shut off unit power supply only if necessary. Remove heating controls compartment access door. Shut off main manual gas valves and pilot manual gas valves.

Intermittent Pilots (48MA) Ð Pilot ¯ame should be approximately 1 to 11¤2 in. high.

ADJUSTMENT

1.Turn system switch to OFF position.

2.If intending to adjust every zone, disconnect main gas valve wires from terminal W on pilot switches in each zone.

		LEGEND
CCP	Ð	Capacity Control Pressure Switch	LPS	Ð	Low-Pressure Switch
DLT	Ð	Discharge Line Thermostat	OFM	Ð Outdoor (Condenser) Fan Motor
FCPS	Ð	Fan Cycling Pressure Switch	TXV	Ð	Thermostatic Expansion Valve
FP	Ð	Fusible Plug			Hand Valve
HGBP	Ð	Hot Gas Bypass
HPS	Ð	High-Pressure Switch			Auto. Valve
IFM	Ð	Indoor (Evaporator) Fan Motor
LLS	Ð	Liquid Line Solenoid			Capilliary

Fig. 31 Ð Refrigerant Piping Schematic (10-Zone Unit Shown Ð 8- and 12-Zone Units Similar)

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