47
8. Adjust high--stage pressure to specified setting by
turning the plastic adjustment screw clockwise to
increase pressure, counter--clockwise to decrease
pressure.
9. Set room thermostat to call for low--stage heat. Adjust
low--stage pressure to specified setting.
10. Replace regulator cover screw(s) when finished.
11. With burner access panel removed, observe unit
heating operation in both high stage and low stage
operation. Observe burner flames to see if they are
blue in appearance, and that the flames are
approximately the same for each burner.
12. Turn off unit, close manual gas shut off valve, remove
pressure manometer and replace the 1/8 in. pipe
fitting on the gas manifold. See Fig. 56.
Burner Ignition
Unit is equipped with a direct spark ignition 100% lockout
system. Integrated Gas Unit Controller (IGC) is located in
the control box. See Fig. 57. The IGC contains a
self--diagnostic LED (light--emitting diode). A single LED
(see Fig. 61) on the IGC provides a visual display of
operational or sequential problems when the power supply
is uninterrupted. When a break in power occurs, the IGC
will be reset, resulting in a loss of fault history, and the
indoor evaporator fan ON/OFF times will be reset. The
LED error code can be observed through the viewport.
During servicing refer to the label on the control box
cover or Table 11 for an explanation of LED error code
descriptions.
IMPORTANT
: Refer to Troubleshooting Tables 16 and
17 for additional information.
Table 11 – LED Error Code Description*
LED INDICATION
ERROR CODE
DESCRIPTION
ON
Normal Operation
OFF
Hardware Failure
2 Flashes
Limit Switch Fault
3 Flashes
Flame Sense Fault
4 Flashes
4 Consecutive Limit Switch Faults
5 Flashes
Ignition Lockout Fault
6 Flashes
Induced---Draft Motor Fault
7 Flashes
Rollout Switch Fault
8 Flashes
Internal Control Fault
9 Flashes
Software Lockout
LEGEND
LED
--- Light Emitting Diode
* A 3 – second pause exists between LED error code flashes. If
more than one error code exists, all applicable codes will be
displayed in numerical sequence.
If lockout occurs, unit can be reset by interrupting power
supply to unit for at least 5 seconds.
Orifice Replacement
This unit uses orifice type LH32RFnnn (where nnn
indicates orifice reference size). When replacing unit
orifices, order the necessary parts through the Carrier
Replacement Components Division (RCD). See Table 12
for available orifice sizes. See Table 14 for orifice sizes
for Natural Gas and LP fuel usage at various elevations
above sea level. Never drill or plug orifices for operation.
Check that each replacement orifice is tight at its threads
into the manifold pipe and that orifice projection does not
exceed maximum value. See Fig. 54.
0.18” (4.60 mm)
0.12 - 0.14”
(3.05 - 3.56 mm)
SPARK GAP
NOTE: SPARK GAP MUST BE AT
THE BOTTOM OF THE BURNER.
IGNITER AND SENSOR LOCATIONS
(BRACKET HEAT COVER NOT SHOWN FOR CLARIY
9 CELL
50HE400026
C12546
Fig. 59 -- Typical MRT Spark Adjustment
48H
C
Summary of Contents for 48HC D17 Series
Page 77: ...77 APPENDIX IV WIRING DIAGRAMS C12616 Fig 77 48HC D17 D28 Power Diagram 208 230 3 60 48HC...
Page 78: ...78 APPENDIX IV WIRING DIAGRAMS C12617 Fig 78 48HC D17 D28 Power Diagram 460 3 60 48HC...
Page 79: ...79 APPENDIX IV WIRING DIAGRAMS C12618 Fig 79 48HC D17 D28 Power Diagram 575 3 60 48HC...
Page 86: ...86 APPENDIX IV WIRING DIAGRAMS C13767 Fig 86 RTU OPEN Wiring Diagram 48HC...
Page 87: ...87 APPENDIX IV WIRING DIAGRAMS C13768 Fig 87 RTU OPEN Wiring Diagram with Humidi MiZer 48HC...
