Bryant 577D----A Check for Refrigerant Leaks, Start-UpAdjustments, Monoport Burner

BURNER FLAME

BURNER

MANIFOLD

C99021

	Fig. 21 - Monoport Burner
A	LIMIT SWITCHES
--	Normally closed limit switch (LS) completes the control circuit.
--
	Should the leaving-air temperature rise above the maximum
577D
	allowable temperature, the limit switch	opens and the control
	circuit “breaks.” Any interruption in the	control circuit instantly
	closes the gas valve and stops gas flow to the burners. The blower
	motor continues to run until LS resets. The furnace board STATUS
	LED will display STATUS CODE 33.
	When the air temperature at the limit	switch drops to the

low-temperature setting of the limit switch, the switch closes and completes the control circuit. The direct-spark ignition system cycles and the unit returns to normal heating operation.

ROLLOUT SWITCH

The function of the rollout switch is to close the main gas valve in the event of flame rollout. The switch is located above the main burners. When the temperature at the rollout switch reaches the maximum allowable temperature, the control circuit trips, closing the gas valve and stopping gas flow to the burners. The indoor fan motor (IFM) continues to run until switch is reset. The furnace board STATUS LED will display STATUS CODE 33.

CONTINUOUS FAN MODE

When continuous fan operation is requested by the UI indoor fan motor will operate at continuous blower airflow. Continuous fan operation is programmable. See the UI Owner’s Manual for detailed instructions. Terminal EAC-1 is energized as long as the indoor fan motor is energized.

During a call for gas heat, the Evolution control will transition the indoor fan motor to continuous blower airflow or gas heat airflow, whichever is lowest. The indoor fan motor will remain ON until the burners ignite, then shut OFF and remain OFF for the blower-ON delay allowing the heat exchangers to heat up more quickly, then restarts at the end of the blower-ON delay period.

The indoor fan motor will revert to continuous-blower airflow after the gas heating cycle is completed.

When the UI “calls for cooling”, the indoor fan motor will switch to operate at cooling airflow. When the call for cooling is satisfied, the indoor fan motor will operate an additional 90 seconds at cooling airflow before transitioning back to continuous-blower airflow.

When the call for continuous fan is removed, the indoor blower will continue operating for an additional 5 seconds before shutting down, if no other function requires blower motor operation.

COMPONENT TEST

The Evolution Furnace Board features a gas component test system to help diagnose a system problem in the case of a gas component failure. To initiate the component test procedure, ensure that there are no UI inputs to the control (the ABCD connector can be removed from the Evolution control board for this operation) and all time delays have expired. Turn on setup switch SW1-6.

NOTE: The component test feature will not operate if the control is receiving any UI signals or until all time delays have expired.

The component test sequence is as follows:

1.The control turns the inducer motor ON and keeps it ON through step 3.

2.After waiting 10 seconds, the control turns the igniter ON for 15 seconds, then OFF.

3.The control then turns the indoor fan motor on for 15 seconds, then OFF.

4.After shutting the blower motor OFF, the control runs the inducer for 10 seconds, then turns it OFF.

NOTE: The EAC terminals are energized when the blower is operating.

After the component test is completed, one or more status codes (11, 25, or 41) will flash. See component test section or Status Code Label for explanation of status codes.

NOTE: To repeat component test, turn setup switch SW1-6 to OFF and then back ON.

Check for Refrigerant Leaks

Locate and repair refrigerant leaks and charge the unit as follows:

1.Use both high- and low-pressure ports to relieve system pressure and reclaim remaining refrigerant.

2.Repair leak following accepted practices.

NOTE: Install a filter drier whenever the system has been opened for repair.

3.Check system for leaks using an approved method.

4.Evacuate refrigerant system and reclaim refrigerant if no additional leaks are found.

5.Charge unit with Puron (R-410A) refrigerant, using an accurate scale. Refer to unit rating plate for required charge.

Start-Up Adjustments

Complete the required procedures given in the Pre-Start-Up section before starting the unit. Do not jumper any safety devices when operating the unit. Do not operate the unit in cooling mode when the outdoor temperature is below 40°F (4°C) (unless low-ambient operation is enabled in the UI). Do not rapid cycle the compressor. Allow 5 min. between “on” cycles to prevent compressor damage.

CHECKING COOLING AND HEATING CONTROL OPERATION

See UI Installation Instructions for detailed system CHECKOUT. CHECKING AND ADJUSTING REFRIGERANT CHARGE

The refrigerant system is fully charged with Puron (R-410A) refrigerant and is tested and factory sealed.

NOTE: Any adjustment to refrigerant charge must be done with unit operating in HIGH stage.

NOTE: Adjustment of the refrigerant charge is not required unless the unit is suspected of not having the proper R-410A charge. The charging label and the tables shown refer to system temperatures and pressures in cooling mode only. A refrigerant charging label is attached to the outside of the unit.

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