Bryant 340MAV Ðspeed Selector, Check Safety Controls Check Primary Limit Control, Checklist

3.Adjust temperature rise by adjusting blower speed. Increase blower speed to reduce temperature rise. Decrease blower speed to increase temperature rise.

WARNING: Disconnect 115-v electrical power before changing speed tap. Failure to follow this warning could result in personal injury.

4.To change blower motor speed selections for heating mode, remove blower motor lead from control center HEAT terminal. (See Fig. 25.) Select desired blower motor speed lead from 1 of the other terminals and relocate it to HEAT terminal. See Table 12 for lead color identification. Recon- nect original lead on SPARE terminal.

Follow this same procedure for proper selection of COOL speed selection.

TABLE 12ÐSPEED SELECTOR

		FACTORY-
COLOR	SPEED	SHIPPED
		CONNECTION
Black	High	Cool
Yellow (When Present)	Medium High	Spare
Blue	Medium Low	Heat
Red	Low	Spare
White	Common	Com

C.Blower Off Delay (Heat Mode)

The main blower off time delay period is factory-set at 135 sec and is not field-adjustable.

D.Set Thermostat Heat Anticipator

Thermostat heat anticipator must be set to match amp draw of components in R-W circuit. Accurate amp draw measurements can be obtained at thermostat subbase terminals R and W.

Fig. 46 illustrates an easy method of obtaining these measure- ments. Amp reading should be taken after blower motor has started. See thermostat manufacturer's instructions for adjusting heat anticipator and for varying heating cycle length.

CHECK SAFETY CONTROLS

I.CHECK PRIMARY LIMIT CONTROL

This control shuts off combustion control system and energizes air-circulating blower motor if furnace overheats. Recommended method of checking this limit control is to gradually block off return air after furnace has been operating for a period of at least 5 minutes. As soon as limit control has shut off burners, return-air opening should be unblocked to permit normal air circulation. By using this method to check limit control, it can be established that limit is functioning properly and operates if there is a restricted return-air supply or motor failure. If limit control does not function during this test, cause must be determined and corrected.

II.CHECK PRESSURE SWITCH

This control proves operation of draft inducer. Check switch operation as follows:

1. Turn off 115-v power to furnace.

THERMOSTAT SUBBASE

TERMINALS WITH

THERMOSTAT REMOVED

HOOK-AROUND

VOLT/AMMETER

R Y W G

10 TURNS

FROM UNIT 24-VOLT

TERMINAL BLOCK

EXAMPLE:	5.0 AMPS ON AMMETER	= 0.5 AMPS FOR THERMOSTAT SETTING
	10 TURNS AROUND JAWS

A80201

Fig. 46ÐAmp Draw Check with Ammeter

2.Remove main furnace door and disconnect inducer motor lead wires from wire harness.

3.Turn on 115-v power to furnace.

4.Set thermostat to call for heat and wait 1 minute. When pressure switch is functioning properly, hot surface ignitor should NOT glow, and control center diagnostic light flashes a Status Code 31. If hot surface ignitor glows when inducer motor is disconnected, shut furnace down immedi- ately. Determine reason pressure switch did not function properly and correct condition.

5.Turn off 115-v power to furnace.

6.Reconnect inducer motor leads, reinstall main furnace door, and turn on 115-v power supply.

CHECKLIST

1.Put away tools and instruments. Clean up debris.

2.Verify manual reset switch has continuity.

3.Verify that blower and control access doors are properly installed.

4.Cycle test furnace with room thermostat.

5.Check operation of accessories per manufacturer's instruc- tions.

6.Review User's Guide with owner.

7.Leave literature packet near furnace.

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