York D2CG300 User Manual

3. To increase the gas pressure, turn the adjusting screw

clockwise.

±

The pilot flame should envelope the end of the flame sensor. Refer
to Proper Flame Adjustment figure. To adjust pilot flame, (1)
remove pilot adjustment cover screw, (2) increase or decrease the
clearance for air to the desired level, (3) be sure to replace cover
screw after adjustment to prevent possible gas leakage.

Put the system into operation and observe through complete
cycle to be sure all controls function properly.

To check or change burners, pilot or orifices, CLOSE MAIN
MANUAL SHUT-OFF VALVE AND SHUT OFF ALL ELECTRIC
POWER TO THE UNIT.

1. Remove the screws holding either end of the manifold to

the burner supports.

2. Open the union fitting in the gas supply line just upstream

of the unit gas valve and downstream from the main manual
shut-off valve.

3. Remove the gas piping closure panel.

4. Disconnect wiring to the gas valves and spark ignitors.

Remove the manifold-burner gas valve assembly by lifting
up and pulling back.

Burners are now accessible for service.

Reverse the above procedure to replace the assemblies. Make
sure that burners are level and seat at the rear of the heat
exchanger.

Adjust burner shutters so no yellow flame is observed in the
heat exchanger tubes. 

The RPM of the supply air blower will depend on the required CFM,
the unit accessories or options and the static resistances of both
the supply and the return air duct systems. With this information,
the RPM for the supply air blower and the motor pulley adjustment
(turns open) can be determined from the Blower Performance
Data  Table.

A high speed drive accessory 1LD0435 (containing a smaller
blower pulley and shorter belts) is available for applications
requiring the supply air blower to produce higher CFM’s and/or
higher static pressures. Refer to the Blower Motor and Drive
Data Table.

Note the following:

1. The supply air CFM must be within the limitations shown in

Unit Application DataTable.

2. Pulleys can be adjusted in half turn increments.

3. The tension on the belts should be adjusted as shown in

the belt adjustment figure below.

Start the supply air blower motor. Adjust the resistances in both
the supply and the return air duct systems to balance the air
distribution throughout the conditioned space. The job
specifications may require that this balancing be done by
someone other than the equipment installer.

To check the supply air CFM after the initial balancing has been
completed:

1. Remove the two 5/16" dot plugs from the blower motor and

the filter access panels.

1/8" GAP BETWEEN CARRY-OVER 

TUBE  AND FLAME SENSOR BULB

CARRY-OVER TUBE

FLAME SENSOR BULB

BURNER ASSEMBLY BRACKET

FIG. 15 - PROPER FLAME ADJUSTMENT

FIG. 16 - TYPICAL FLAME APPEARANCE

FIG.17 - BELT ADJUSTMENT

530.18-N11Y

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Unitary Products Group