12. Check the pilot flame. The flame should engulf the flame
sensor rod with a flame about the size of a fist.
13. Check the pilot line gas pressure. It should be between 6
and 8” (15 and 20 cm) w.c.
14. SLOWLY open the firing valve. This will allow the main
burner to ignite. Check for proper burner operation.
15. With the unit on high fire, check and record the manifold
pressure by using the manifold pressure port on the gas
valve. Confirm the gas pressure matches the name plate.
To turn the unit off, turn the “on/off” switch to “off”.
High and Low Temperature Safeties
The unit includes a manual reset high limit. If the maximum
rated discharge temperature (160 °F/71°C) is exceeded, the
safety will open and the unit will shut down. The reset button
is located on the safety typically located in the gas weather
housing. This safety was tested in the factory and does not
need to be tested in the field.
High Limit Test
Some units may require a field test of the high limit safety. This
test can be performed as follows;
1. With the unit off and the disconnect open, disconnect
the neutral wire to the supply fan contactor coil. This will
disable the supply fan.
2. Remove the supply air duct sensor form the duct so the
controller cannot detect heat in the duct.
3. Set up a portable temperature sensor to as close to the
furnace as possible monitor the unit temperature.
4. Close the disconnect and start the unit. Raise the supply
air setpoint to max to call for full fire.
5. Closely monitor the unit temperature. The high limit
should open at (160 °F (71°C) and shut the unit down. If
the unit temperature exceeds 200°F (93°C) shut the unit
down and trouble shoot the high limit.
6. Once the high limit has been tested, reconnect the supply
fan contactor wire, the supply air duct sensor and rest the
discharge air temperature setpoint back to the correct
setting.
Figure 8:
The unit also includes an automatic reset low limit.
This safety will shut the unit down if the supply air temperature
is too low (for example, a heat failure). Once the supply air
temperature rises above the minimum setpoint, the safety will
reset and the unit will operate.
MANUAL RESET HIGH LIMIT SWITCH
FIGURE 8: LOW LIMIT SAFETY SWITCH
PRIMARY FLAME SAFEGUARD RESET
22
AW-I
INSTALLATION INSTRUCTIONS
AW-I - Manual
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