3.Reverse any two of the unit power leads.
4.Reenergize to the compressor. Check pressures.
The suction and discharge pressure levels should now move to their normal start-up levels.
NOTE: When the compressor is rotating in the wrong direc- tion, the unit will make an elevated level of noise and will not provide cooling.
X. COOLING
Set space thermostat to OFF position. To start unit, turn on main power supply. Set system selector switch at COOL position and fan switch at AUTO. position. Adjust thermo- stat to a setting below room temperature. Compressor starts on closure of contactor.
Check unit charge. Refer to Refrigerant Charge section on page 38.
Reset thermostat at a position above room temperature. Compressor will shut off. Evaporator fan will shut off after a 30-second delay.
A. To Shut Off Unit
Set system selector switch at OFF position. Resetting ther- mostat at a position above room temperature shuts unit off temporarily until space temperature exceeds thermostat setting. Units are equipped with Cycle-LOC™ protection device. Unit shuts down on any safety trip, and indicator light on thermostat comes on. Check reason for all safety trips.
Compressor restart is accomplished by manual reset at the thermostat by turning the selector switch to OFF and then to ON position.
XI. MAIN BURNERS
Main burners are factory set and should require no adjustment.
TO CHECK ignition of main burners and heating controls, move thermostat set point above room temperature and ver- ify that the burners light and evaporator fan is energized. Check heating effect, then lower the thermostat setting below the room temperature and verify that the burners and evaporator fan turn off.
Refer to Tables 29A and 29B for the correct orifice to use at high altitudes.
Table 29A — Altitude Compensation* —
581B036-072 Standard Units
| 72,000 AND 115,000 BTUH | 150,000 BTUH |
ELEVATION | NOMINAL INPUT | NOMINAL INPUT |
Natural | Liquid | Natural | Liquid |
(Ft) | Gas | Propane | Gas | Propane |
| Orifice | Orifice | Orifice | Orifice |
| Size† | Size† | Size† | Size† |
0-2,000 | 33 | 43 | 30 | 38 |
2,000 | 36 | 44 | 31 | 39 |
3,000 | 36 | 45 | 31 | 40 |
4,000 | 37 | 45 | 32 | 41 |
5,000 | 38 | 46 | 32 | 42 |
6,000 | 40 | 47 | 34 | 43 |
7,000 | 41 | 48 | 35 | 43 |
8,000 | 42 | 49 | 36 | 44 |
9,000 | 43 | 50 | 37 | 45 |
10,000 | 44 | 50 | 39 | 46 |
11,000 | 45 | 51 | 41 | 47 |
12,000 | 46 | 52 | 42 | 48 |
13,000 | 47 | 52 | 43 | 49 |
14,000 | 48 | 53 | 44 | 50 |
*As the height above sea level increases, there is less oxygen per cubic foot of air. Therefore, heat input rate should be reduced at higher altitudes.
†Orifice available through your local Bryant distributor.
Table 29B — Altitude Compensation* —
581B036-072 Low NOx Units
| 60,000 AND 90,000 BTUH | 120,000 BTUH |
ELEVATION | NOMINAL INPUT | NOMINAL INPUT |
Natural | Liquid | Natural | Liquid |
(Ft) | Gas | Propane | Gas | Propane |
| Orifice | Orifice | Orifice | Orifice |
| Size† | Size† | Size† | Size† |
0-2,000 | 38 | 45 | 32 | 42 |
2,000 | 40 | 47 | 33 | 43 |
3,000 | 41 | 48 | 35 | 43 |
4,000 | 42 | 49 | 36 | 44 |
5,000 | 43 | 49 | 37 | 45 |
6,000 | 43 | 50 | 38 | 45 |
7,000 | 44 | 50 | 39 | 46 |
8,000 | 45 | 51 | 41 | 47 |
9,000 | 46 | 52 | 42 | 48 |
10,000 | 47 | 52 | 43 | 49 |
11,000 | 48 | 53 | 44 | 50 |
12,000 | 49 | 53 | 44 | 51 |
13,000 | 50 | 54 | 46 | 52 |
14,000 | 51 | 54 | 47 | 52 |
*As the height above sea level increases, there is less oxygen per cubic foot of air. Therefore, heat input rate should be reduced at higher altitudes.
†Orifice available through your local Bryant distributor.
XII. HEATING
1.Purge gas supply line of air by opening union ahead of the gas valve. If gas odor is detected, tighten union and wait 5 minutes before proceeding.
2.Turn on electrical supply and manual gas valve.
3.Set system switch selector at HEAT position and fan switch at AUTO. or ON position. Set heating temper- ature lever above room temperature.
4.The induced-draft motor will start.
5.After a call for heating, the main burners should light within 5 seconds. If the burner does not light, then there is a 22-second delay before another 5-second try. If the burner still does not light, the time delay is repeated. If the burner does not light within 15 minutes, there is a lockout. To reset the control, break the 24-v power to W1.
6.The evaporator-fan motor will turn on 45 seconds after burner ignition.
7.The evaporator-fan motor will turn off in 45 seconds after the thermostat temperature is satisfied.
8.Adjust airflow to obtain a temperature rise within the range specified on the unit nameplate.
NOTE: The default value for the evaporator-fan motor on/off delay is 45 seconds. The Integrated Gas Unit Controller (IGC) modifies this value when abnormal limit switch cycles occur. Based upon unit operating conditions, the on delay can be reduced to 0 seconds and the off delay can be extended to 180 seconds. When one flash of the LED (light-emitting diode) is observed, the evaporator-fan on/off delay has been modified.
If the limit switch trips at the start of the heating cycle dur- ing the evaporator on delay, the time period of the on delay for the next cycle will be 5 seconds less than the time at which the switch tripped. (Example: If the limit switch trips at 30 seconds, the evaporator-fan on delay for the next cycle will occur at 25 seconds.) To prevent short-cycling, a 5-second reduction will only occur if a minimum of 10 minutes has elapsed since the last call for heating.
The evaporator-fan off delay can also be modified. Once the call for heating has ended, there is a 10-minute period dur- ing which the modification can occur. If the limit switch trips during this period, the evaporator-fan off delay will increase by 15 seconds. A maximum of 9 trips can occur, extending the evaporator-fan off delay to 180 seconds.
To restore the original default value, reset the power to the unit.
