Reznor PDF2SF Unit Installation Manual - Manual (Page 25)

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COMPONENT FUNCTIONS
Comfort Alert™ Diagnostics -The Comfort Alert
diagnostics module troubleshoots heat pump and air
conditioning system failures and accurately detects the
cause of electrical and system related failures without
any sensors. A flashing LED indicator communicates the
ALERT code to quickly direct the technician to the root
cause of a problem.
Flame Roll-Out Control - The flame roll-out control acts to
verify that the burner flame is being drawn into the heat
exchanger tubes. If the burner flame is not being drawn
into the heat exchanger tubes, the roll-out control will
open within several seconds and the integrated control
diagnostic light will flash one time. If the limit opens, the
integrated control diagnostic will flash one time. The
circulating air blower will continue to operate while the
flame roll-out control is open.
Flame Sensor - The flame sensor acts to prove that flame
has carried over from the ignitor to the right-most burner. If
no flame is sensed, the unit will be shut down automatically.
Dual Pressure Switch - The dual pressure switch verifies
that the inducer motor is drawing the combustion gases
through the heat exchanger tubes and venting the
gases through the vent system for both high and low fire
conditions.
Gas Valve - The gas valve controls the flow of gas to the
burners in both low and high fire. When the gas valve is
energized it automatically opens and regulates the gas
pressure in the manifold. See Figure 10 below.
REPLACEMENT PARTS
Replacement parts are available through all Nordyne
distributors. Please have the complete model and serial
number of the unit when ordering replacement parts.
Electrical:
• Capacitors • Pressure Switches
• Compressors • Relays
• Contactors • Reversing Valve Solenoid
• Defrost Control Board • Temperature Limit Switches
• Gas Valves • Thermostats
• Ignition Controls • Time Delay Relays
• Ignitors/Flame Sensors • Transformers
Motors:
• Blower Motor
• Fan Motor
• Inducer Blower Motor
Components:
• Blower Assembly • Fan Grille
• Burner Manifold • Filter/Driers
• Burners/Orifices • Gaskets
• Cabinet Panels • Heat Exchanger
• Expansion Valves • Reversing Valve
IN
ON
OFF
Inlet
Pressure
Tap
Inlet
Pressure
Tap
Manifold
pressure
Tap
Manifold
pressure
Tap
2-STAGE GAS VALVES
Model VR8205Q2381
Model VR9205Q1028
ON / OFF
Knob
ON / OFF
Switch
HI Input
Adjusting Screw
Lo Input
Adjusting Screw
HI Input
Adjusting
Screw
Lo Input
Adjusting
Screw
Figure 10. HI & LO Input Adjusting Screws
Over-Temperature Limit Control - The over-temperature
limit control prevents the air temperature leaving the unit
from exceeding the maximum outlet air temperature. If the
limit opens, the integrated control diagnostic will flash one
time. The circulating air blower will continue to operate
while the over-temperature limit control is open.