T418 Oau Low Cfm; T418 Oau General Alarm; Check Diagnostic Leds - Carrier 48HC 04-28 Controls, Start-Up, Operation And Troubleshooting

determine which one is having the problem. In test mode run
the components individually to determine which is causing the
problem. If the Shut Down on fan failure configuration is set to
→
Yes (Configuration OAU
shutdown with this alarm active. If set to no, the ERV will con-
tinue to run as if the alarm did not occur, outside air CFM, ex-
haust CFM, or pre-conditions might not be achievable if a mo-
tor fails. The two classes of motor status are explained below.
Intake and Exhaust Motor Status
If any one of the ERV's outside or exhaust motors detects a
problem, it will close its build in normally open alarm contact,
which will be seen as 24vac at EXCB J8-3. The EXCB's D18
LED will be turn on and the OAU Motor Failure Alarm point
will be turned to on (Operating Modes
On). This alarm will automatically reset when the motor opens
its alarm relay. This alarm is tripped by one of the following:
phase loss, locked rotor, thermal overload, communication er-
ror, incorrect signal, or a fan failure.
Wheel Status
This alarm will occur when the ERV wheel is turned on and the
wheel proxy sensor does not detect wheel motion within the set
time. It will open its contact which energizes the normally
closed rotation monitor relay. This is seen as 24vac at EXCB
J5-3 and causes the alarm. The EXCB's D12 LED will be
turned on and the OAU Motor Failure Alarm point will be
turned to on (Operating Modes
This alarm will automatically reset when motion is detected.
Possible causes of this alarm are: the wheel belt breaking or
slipping, wheel motor failure, proxy sensor failure or incorrect
setting, or wiring error.

T418 OAU LOW CFM

This alarm indicates that the ERV cannot bring in the desired
amount of outside air. The alarm occurs when the actual out-
side air CFM (Operating Modes
10% of the commanded outside air CFM (Operating Modes
→ →
OAU C.OA) after 10 minutes. This alarm will not occur
in test mode or defrost mode. The Rooftop unit might be able
to help by ramping its indoor fan up. Refer to the base controls,
start up, operation, and troubleshooting manual for details. The
OAU Low CFM Alarm point will be turned to on (Operating
→ →
Modes OAU ALM.3 = On). This alarm will automatical-
ly reset if the actual CFM is within 10% of the commanded
CFM. Possible causes of this are: outside air CFM setpoint set
too high, dirty filter or plugged screen, pressure tubing wrong
or disconnected, wrong OA CFM curve programmed, or RTU
indoor fan speed running too low.

T418 OAU GENERAL ALARM

This alarm is not currently used by the ERV.

Check Diagnostic LEDs

Use the on board LEDs to assist in troubleshooting the Ener-
gyX system. The EnergyX Control Board (EXCB) and the
®
Universal Protocol Converter (UPC) each have LEDs that can
help in the troubleshooting process. See Tables 25-27.
The EXCB has five green LEDs and one red LED. The red LED
is for power indication and the green LEDs are status indicators.
The UPC has seven LEDs. There are four communication
LEDs and three status LEDs. The communication LEDs indi-
cate if the translator is speaking to the devices on the network
and should reflect communication traffic based on the baud
rate set. The higher the baud rate, the LEDs would become
more solid.
→
OAU.F = Yes), the ERV will
→ →
OAU ALM.1 =
→ →
OAU ALM.1 = On).
→ →
OAU A.OA) is less than
Table 25 — EXCB LED Indicators
LED COLOR DESCRIPTION
D9 Red 24vAC board power
D2 Green Run light Flashing
D12 Green ERV Wheel Status Alarm
ERV Wheel Frost
D14 Green
Protection
D16 Green ERV Dirty Filter Alarm
D18 Green ERV Blower Status Alarm
Table 26 — EXUPC LED Indicators
LED COLOR DESCRIPTION
Power Green Power Indicator
Port 1 Receiving
Rx1 Green
Data
Port 2 Receiving
Rx2 Green
Data
Port 1
Tx1 Green
Transmitting Data
Port 2
Tx2 Green
Transmitting Data
Run Green Run indicator
Internal Error
Error Red
indicator
* Modbus is a registered trademark of Schneider Electric.
Table 27 — EXUPC LED Flash Code Diagnostics
Error LED
Run LED Status
Status
Off
2 flashes,
alternating with
Run LED
3 flashes then off
2 flashes per second
4 flashes then
pause
1 flash per
second
On
On
5 flashes per second
Off
7 flashes per
second,
7 flashes per second
alternating with
Run LED
14 flashes per
14 flashes per second,
second alternating with
Run LED
Alternating with Alternating with
Error Run
67
STATUS IF LIGHT
IS LIT
Board has power
ERV is Running
ERV Wheel not
rotating when it
should be
ERV detects frost on
the wheel and
running in Frost
Mode
Dirty Filter
Fan Failure
STATUS IF LIGHT IS LIT
Lights when power is being
supplied to the translator.
Lights when the translator
receives data from
ComfortLink MBB via LEN
Lights when the translator
receives data from the
Modbus* EXCB
Lights when the translator
transmits data to the
ComfortLink MBB via LEN
Lights when the translator
transmits data to the Modbus
EXCB
Lights based on translator
health. See Table 27.
Lights based on translator
health, See Table 27.
ERV Module Status
Normal
5 minute auto - restart delay
after system error
Module has just been
formatted
Two or more devices on this
network have the same
ARC156 network address
Module is alone on the network
Operation halted after frequent
system errors or control
programs halted
Operation start - up aborted.
Boot is running
Firmware transfer in progress.
Boot is running
Ten second recovery period
after brownout
Brownout
Restoring memory from
Archive