American Standard UHMB060ACV3VB Series Service Facts page 47

DEFINITION:
GND ERR - Incoming or chassis
ground connection is not sensed
POLARITY ERR – Incoming high
voltage wiring is reversed
Reverse 120 vac
power leads to
furnace wiring
Reconnect power
Check operation
Correct earth
ground.
Check operation
UHM-DHM-SF-1V-EN
6 Flash Fault LED
Scroll through
User Interface to
View number 1 of
Last 4 Faults
User Interface
shows a GND
POLARITY ERR?
Connect volt meter
to white incoming
neutral wire and
green earth ground
Disconnect
incoming electrical YES
read ~120 vac?
power to furnace
Connect volt meter
to black incoming
and chassis ground
at burner box
Disconnect
incoming electrical NO
read ~120 vac?
power to furnace
incoming electrical
power to furnace
Check / correct all
connections within
Check operation
Service Facts
FAULT or
Is there a
Does meter
NO voltage greater
than 10 VAC
NO
NO
Does meter
YES
Disconnect
ground
furnace for
continuity
See next page for
additional 6 flash
faults
Correct neutral
and ground
YES problem. Furnace
must be on a
dedicated circuit.
47