Installation manual

170761-UIM-B-0406
10 Unitary Products Group
If the control displays an operational mode other than LED2 (Green)
ON and LED1 (Red) 1 flash indicating a heat pump with a single stage
compressor, an error condition exists. Check all wiring of the reversing
valve (RV and RVG terminals) and compressor outputs (M, M1, and M2
terminals). Cycle 24 VAC power to the control and check the opera-
tional mode again.
STATUS MODE DISPLAY
The control also provides status codes using the LED’s. Status codes
indicate the state of operation of the unit but do not represent a fault.
Table 4 describes the LED displays during status codes. Status codes
will not be displayed when a fault code is present.
During the following conditions, the control will not energize the X/L out-
put.
FAULT CODE DISPLAY
X/L Output
The X/L terminal of the heat pump control is typically connected to the
X/L input of the room thermostat. The thermostat uses this signal to
notify the homeowner of a problem with the heat pump using an LED or
LCD display. When the control energizes the X/L terminal, the thermo-
stat displays the flash code so the homeowner can see it.
The heat pump control informs the homeowner of the type of condition
that is present using flash codes. Table 5 shows the condition catego-
ries and the corresponding X/L flash codes.
The control will continue to energize the X/L output for fault codes hav-
ing an X/L code of 4 flashes even after the thermostat calls are
removed. The control does this to notify the installer or homeowner that
a significant problem with the wiring or system configuration is present
and needs to be corrected.
The control will continue to energize the X/L output until the condition
that caused the fault condition no longer exists.
LED Display
The control will display any fault code that is currently active using the
LED’s. The control will display the fault code, pause two seconds, and
display the fault again. The control will continue the fault code display
until the condition that caused the fault code no longer exists. If multiple
fault codes are present at the same time, the control will display only
the most recent fault. The other active errors may be accessed from
memory using the LAST ERROR pushbutton.
Operational Fault Codes
Table 6 shows the operational faults that the control can detect. The
control displays this type of error by flashing LED1 (Red) only. LED1
(Green) is not energized. These faults typically occur when the heat
pump has been operating and a problem occurs.
Sensor or Switch Fault Codes
Table 7 shows the faults that the control can detect when a problem is
present with a sensor or switch. The control displays this type of error
by energizing LED1 (Red) constantly and flashing LED2 (Green).
These faults typically occur when the heat pump has been operating
and a problem occurs with a sensor or its wiring. These faults could also
occur during installation as the heat pump is configured.
TABLE 4:
Status Code Display
Description
LED1
(Red)
LED2
(Green)
No power to control OFF OFF
First-stage compressor operation – not
applicable to single stage compressor
OFF ON
Second-stage or full capacity compressor
operation
ON ON
Control normal operation – no
call for compressor
OFF
2 sec ON
2 sec OFF
Control normal operation – call for com-
pressor and ASCD timer (5 min.) is active
OFF
Rapid
Flash
No fault codes in memory – Initiated
by LAST ERROR pushbutton
22
Fault code memory cleared – Initiated
by LAST ERROR pushbutton
33
TABLE 5:
X/L Output Categories
Condition Category X/L
Soft Lockout – Reset with interruption of thermostat
call following correction of fault condition
2 flashes
Hard Lockout – Reset by cycling power
to system
3 flashes
Wiring, sensor or control setting related error 4 flashes
TABLE 6: Operational Fault Codes
Description
LED1
(Red)
LED2
(Green)
X/L
Operational Faults
Control Failure that still allows fault
code output
ON OFF 4 if possible
High-pressure switch fault
(not in lockout yet)
1OFF OFF
High-pressure switch lockout
(last mode of operation was heat pump)
2OFF
2 (soft)
3 (hard)
High-pressure switch lockout
(last mode of operation was defrost)
3OFF
2 (soft)
3 (hard)
Low-pressure switch lockout 4 OFF
2 (soft)
3 (hard)
Low Voltage (< 19 VAC) preventing
further relay outputs
5OFF OFF
Low Voltage (< 16 VAC) stopped
current relay outputs
6OFF OFF
Pipe Freeze Protection
Timer expiration
7OFF 4
TABLE 7:
Sensor or Switch Fault Codes
Description
LED1
(Red)
LED2
(Green)
X/L
Required Sensor or Switch Faults
Outdoor ambient sensor failure (short) ON 1 2 (soft)
Outdoor ambient sensor failure (open) ON 2 2 (soft)
Liquid line sensor failure (short) ON 3 2 (soft)
Liquid line sensor failure (open) ON 4 2 (soft)
Optional Discharge Line Sensor Faults
High discharge line temperature ON 5
2 (soft)
3 (hard)
Low discharge line temperature ON 6
2 (soft)
3 (hard)
Discharge line sensor failure (short) ON 7 2 (soft)
Optional Bonnet Sensor Faults
Bonnet sensor failure (short) ON 8 4
Fossil Fuel Mode setting error (FFUEL jumper
in OFF position but bonnet sensor present)
ON 9 4