FloAire INDIRECT FIRED BENT TUBE MODULE - Manual (Page 30)

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11. Discharge/Space Dial Temperature Control – Controls the Discharge or Space temperature to
which the heating module heats to and constantly tries to maintain. Mounted in the unit for
discharge temperature control and remotely for space control.
12. Modulating Furnace Power-vent blower Speed controller – Controls the speed of the power-
vent blower on the modulating furnace to maintain constant combustion efficiency. Dip-switches
de-activated. Non-adjustable, comes pre-programmed from factory.
13. Flame Safety Control – Initiates and monitors flame. Equipped with non-adjustable time settings
for pre-purge, inter-purge, and post-post of the exhaust flue and control cabinet.
14. Power-vent Airflow proving Switch – Normally open, non-adjustable airflow switch. Senses
whether the power-vent blower is running and allows furnace to spark when airflow is proven.
15. High Limit Switch – Normally closed high temperature switch. De-energizes heater circuit on
individual furnace if temperature exceeds mechanical set-point. Automatic recycling. 200°F set-
point.
16. Flame Roll-Out Switch – Normally closed temperature activated switch. Mounted on bracket at
inlet of the upper-most firing tube. Senses for any flame roll-out in the event of a blocked tube,
low airflow, or low gas pressure. If flame-rollout is present, de-energizes heater circuit on
individual furnace. Must be manually reset. 325°F set-point.
17. Power-vent Motor– Induces airflow through heat exchanger and flue of furnaces A) Modulating
furnace variable speed blower motor. B) Non-modulating furnace constant speed blower motor.
Power Vent Motor Orifice Size
Furnace BTU (x1000/hr) Dia. (in.)
400 2.625
300 2.25
200 2.375
150 1.875
18. Spark Igniter – Powered by Flame safety control to initiate light-off.
19. Flame Sensor – Continuously Senses for the presence of flame in heating mode after ignition
has commenced. Wired to Flame Safety Control.
20. On/Off Redundant Gas Valve – On/off gas valve with built in regulator and manual shut off
switch. One used on each furnace gas train.
21. Modulating Gas Valve – Controls the amount of gas to the modulating furnace to meet desired
discharge/Space temperature.
22. Manual Gas Shut-Off Valve - Allows gas flow to burner to be shut off to leak test gas train.
23. Manifold Gas Pressure Gauge – Indicates manifold gas pressure on individual furnace.
24. Main Inlet Gas Pressure Gauge – Indicates inlet gas pressure to unit.
25. Cooling thermostat (Optional) – Senses intake air temperature and initiates call for cooling if
temperature rises above set-point.
26. Cooling Relays (Optional) – Powered by cooling thermostat. Contacts used to send power to
the compressors in the condensing unit during a call for cooling.
27. Remote Panel indicating light Relay (Optional) – Contacts energize appropriate circuits to
indicate to the user that the main Blower is running, there is a call for heat, or clogged filters.
28. Freeze-Stat (Optional) – Senses discharge temperature and shuts down power to the main
blower if the temperature drops below the set-point for a time longer than what is set on the
adjustable dial.
29. Discharge Air Sensor – Used on units with discharge temperature control to sense the
temperature at discharge
30. Exhaust Flue Pipe – Ventilates combustion exhaust between the power-vent discharge and top
of the unit.
31. Dirty Filter Airflow Switch (Optional) – Senses whether the filters at the intake to the main
blower are free of dirt and contaminant.