York D2CG300 User Manual
6. Auxiliary Limit Switch (AUX) This control is located inside
the heat exchanger compartment and is set to open at
190
190
°
F. It is a manual reset switch. If AUX limit trips, then the
primary limit has not functioned correctly., Replace the
primary limit
primary limit
OPERATING INSTRUCTIONS
CAUTION: This furnace is equipped with an intermittent pilot
and automatic re-ignition system. DO NOT attempt
to manually light the pilot.
to manually light the pilot.
TO LIGHT PILOT AND MAIN BURNERS:
1. Turn “off” electric power to unit.
2. Turn room thermostat to lowest setting.
3. Turn gas valve knob to “on” position.
4. Turn “on” electric power to unit.
5. Set room thermostat to desired temperature.
(If thermostat “set” temperature is above room temperature,
pilot burner ignition will occur and, after an interval to prove
pilot flame, main burners will ignite).
pilot burner ignition will occur and, after an interval to prove
pilot flame, main burners will ignite).
TO SHUT DOWN:
1. Turn “off” electric power to unit.
2. Depress knob of gas valve while turning to “off” position.
POST-START CHECK LIST (GAS)
After the entire control circuit has been energized and the
heating section is operating, make the following checks:
heating section is operating, make the following checks:
1. Check for gas leaks in the unit piping as well as the supply
piping.
2. Check for correct manifold gas pressures. See “Checking
Gas Input”.
3. Check the supply gas pressure. It must be within the limits
shown on rating nameplate. Supply pressure should be
checked with all gas appliances in the building at full fire. At
no time should the standby gas line pressure exceed 13",
nor the operating pressure drop below 5.0" for natural gas
units. If gas pressure is outside these limits, contact the
checked with all gas appliances in the building at full fire. At
no time should the standby gas line pressure exceed 13",
nor the operating pressure drop below 5.0" for natural gas
units. If gas pressure is outside these limits, contact the
local gas utility for corrective action.
MANIFOLD GAS PRESSURE ADJUSTMENT
Small adjustments to the high-fire gas flow may be made by
turning the pressure regulator adjusting screw on the automatic
gas valve. Refer to figure below.
turning the pressure regulator adjusting screw on the automatic
gas valve. Refer to figure below.
Adjust as follows:
1. Remove the cap on the regulator. It’s located next to the
push-on electrical terminals.
2. To decrease the gas pressure, turn the adjusting screw
counterclockwise.
I G N . C O N T R O L # 1
I G N . C O N T R O L # 2
I G N I T O R # 1
G V 1
G A S
V A L V E
G V 2
G A S
V A L V E
I G N I T O R # 2
S E N S O R # 2
S E N S O R # 1
R O L L O U T S W .
B U R N E R C O M P A R T M E N T
FIG 13-GAS VALVE AND CONTROLS
HEAT ANTICIPATOR SETPOINTS
It is important that the anticipator setpoint be correct. Too high of
a setting will result in longer heat cycles and a greater
temperature swing in the conditioned space. Reducing the value
below the correct setpoint will give shorter “ON” cycles and may
result in the lowering of the temperture within the conditioned
space.
a setting will result in longer heat cycles and a greater
temperature swing in the conditioned space. Reducing the value
below the correct setpoint will give shorter “ON” cycles and may
result in the lowering of the temperture within the conditioned
space.
PRE-START CHECK LIST
Complete the following checks before starting the unit.
1. Check the type of gas being supplied. Be sure that it is the
same as listed on the unit nameplate.
2. Make sure that the vent and combustion air hoods have been
properly installed.
START-UP
ON-OFF CONTROL
HIGH FIRE ADJ.
(UNDER SCREW)
(UNDER SCREW)
PILOT ADJ.
(UNDER SCREW)
(UNDER SCREW)
FIG. 14 - TYPICAL GAS VALVE
Capacity, MBH
Limit Control
Opens,
°
F
Input
Output
300
240
195
400
320
195
TABLE 10 - LIMIT CONTROL SETTING
Gas Valve
Anticipator Setpoint
1st Stage
2nd Stage
Honeywell VR8440
0.30 amp
0.11 amp
White-Rodgers 36C68
530.18-N11Y
Unitary Products Group
17