Bryant 355CAV Checklist, Check Safety Controls, Check Primary Limit Control

NOTE: When using an electronic thermostat, set cycle rate for 3	2.	Remove control access door and disconnect inducer motor
cycles per hr.		12-pin wire harness at inducer motor.
3. Return setup switch SW1-2 to OFF position and replace	3.	Turn on 115-v power to furnace.
thermostat on subbase.	4.	Set thermostat to “call for heat.” When pressure switches
Check Safety Controls		are functioning properly, status code 42 will flash on fur-
This section covers the safety controls that must be checked		nace control approximately 20 sec after thermostat switch
		is closed. If either a status code 31 or 32 is flashed when
before the installation is complete. The flame sensor, gas valve,
		inducer motor is disconnected, the furnace will shut itself
and pressure switches were all checked in the Start-up procedure
		down	immediately.	Determine the reason	pressure
section as part of normal operation.
		switches did not function properly and correct the condi-
Check Primary Limit Control
		tion.
This control shuts off the gas control system and energizes the
	5.	Turn off 115-v power to furnace.
air-circulating blower motor if furnace overheats.
	6.	Reconnect inducer motor wire harness. Reinstall furnace
1. The recommended method of checking this limit control is
		access door.
to gradually block off return air after furnace has been op-
	7.	Turn on 115-v power to furnace.
erating for a period of at least 5 minutes.
	8.	Reset thermostat to desired temperature.
2. As soon as limit control has shut off burners, a status code
			CHECKLIST
33 will appear on furnace control.
3. The return-air opening should be unblocked to permit	1.	Put away tools and instruments. Clean up debris.
normal air circulation.	2.	Verify flame rollout manual reset switch has continuity.
By using this method to check the limit control, it can be
	3.	Verify	that blower and	main access doors are	properly
established that the limit is functioning properly and the furnace
		installed.
will operate safely if there is a restricted return-air duct or motor
	4.	Cycle test furnace with room thermostat.
failure. If the limit control does not function during this test, the
	5.	Check operation of accessories per manufacturer’s instruc-
cause must be determined and corrected.
Check Pressure Switches		tions.
	6.	Review User’s Manual with owner.
This control proves operation of the draft inducer. Check switch
	7.	Leave literature packet near furnace.
operation as follows:

1. Turn off 115-v power to furnace.

THERMOSTAT SUBBASE TERMINALS WITH THERMOSTAT REMOVED (ANITICIPATOR, CLOCK, ETC.,

MUST BE OUT OF CIRCUIT.)

HOOK-AROUND AMMETER

R Y W G

10 TURNS

FROM UNIT 24-V CONTROL TERMINALS

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

A96316

Fig. 63 - Amp Draw with Ammeter

355CAV

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