Reznor PDH Operation Manual PreevA - Manual (Page 31)

Form O-PreevA, P/N 234661R8, Page 31
4.2 Troubleshooting - Modulating Control Module used on Model RDH Sizes 175-400,
Model RHH, or Model SHH with Gas Control Option AG58 or D12G
The control that operates the furnace has a built-in, self-diagnostic capability. The control continuously monitors its own
operation and the operation of the system. The LED on the control indicates the current state, warnings, failures, and
test modes.
Normal Furnace Operation Display
LED Display Heat Mode Description
OFF Mode (OFF) System Idle - Control board has power, no faults found, no call for heat.
PURGE Mode (Pur)
System is purging the heat exchanger – No gas on, no flame, venter motor runs for the specified
purge timings. Purge cycles occur immediately before and after each burner operation.
IGNITION Mode (Ign)
System is initiating burner operation – Ignitor energized, modulating valve moved to ignition
setting, gas on. Maintained for the trial-for-ignition period and the five-second flame stabilization
period.
WARM-UP Mode
(HEA)
(Board Self Check)
Period between Ignition and Run – System checks completed before modulation control begins.
RUN Mode (run) Normal modulating operation.
Ignition Retry (rEt)
System has had a failed ignition attempt or has lost flame during burner operation and is
beginning another ignition cycle.
3 Character LED
Display used to show
deep modulation board
codes for status, alarm,
and error information.
ID Plug
(unique by
model, heat
section size, &
type of gas)
Deep Modulation (Option AG58 and D12G) Ignition Board
is in the Control Compartment (See FIGURE 1A, page 5.)
Contactor
Signal Input
Terminals (J4)
Board Power
and Signal (J6)
Control Board
Fuse (3A)
Plug Connec-
tion for Board
Control Points
(J8)
• Ball Valve
Actuator Power,
Drive Voltage,
and Feedback
Signal
• Off Board
Digital Venter
Air Pressure
Switch and Unit
Primary Limit
Switch
On board Air Pressure Sensor for Monitoring Inducer Pressure.
Venter Sensing Tubing is connected from Venter housing to "LO"
pressure input point on air sensing transducer.
Gas Manifold PSI Transducer
Plug 3-wire (red, black, and green)
Wiring Connection (J13)
J9, J10, J3, and J2 are
not currently used.
Flame
Sensor
Spade
Connection
(T8)
Inducer
Motor
Capacitor
Spade
Connection
(AUX-L2 T6 )
Inducer Motor Main Power
Connection Spades
(IND-L2 T3 and IND-L1 T2 )
Main Board Supply Power Input
Spades (L1 T1 and L2 T5 )