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4.Make s ure h eater size installed isanapproved
size forunit
and size installed.
NOTE: Fan coilcontrol willnot o perate electric heater until t his
Status Code i sresolved.
If the heater size i sset t hrough the UI, t he
heater willbe operated
as asingle stage heater. Ifstaging isdesired,
the IDR value m ust be read i nbythe unit c ontrol.
STATUS (;ODE 36, H EATER OUTPUT NOT SENSED
WHEN
ENERGIZED
Fan coil c ontrol isprovided withcircuitry todetect presence
ofa
24-vac signal onelectric heater stage i and stage 2outputs.
If fan coil c ontrol energizes
either heater stage and d oes n ot d etect
the 24-vac signal on output, Status Code 36 will b e displayed
on the
STATUS LED, c ontrol willcontinue menergize
heater output(s)
and adjust blower operation
toasafe a irflow level f orenergized
electric heat stage(s).
To findthe fault:
1.Check for24-vac onheater stage outputs.
Fan coil c ontrol
orsensing
circuit may b ebad.
NOTE: It may beuseful asanelectric heater troubleshooting
procedure
todisconnect
the system communications
toforce S tatus
(;ode 16enabling ofemergency
heat mode. It isdifficult toknow
which heater output is energized
or notenergized
in normal
operation.
When u nit i soperated
inemergency
heat mode u sing
electric heaters, bothoutputs areenergized
andde-energized
together.
Terminal strip inputs t ofancoilcontrol canthen be
connected
RtoWtoturn on both e lectric heat outputs.
Heater output
sensing
circuits can t hen b e checked
toresolve Status Code 36or37
problems.
STATUS
(;ODE 41, B LOWER MOTOR FAULT
If MOTOR LED islitand flashing and motor does n ot r un:
1.Check STATUS
LED. IfSTATUS LED isindicating
Status
Code 4 1. m otor control has d etected
that the motor ,,rill n ot
come uptospeed within 3 0 seconds
ofbeing c ommanded
to
run orthat the motor has b een s lowed tobelow 250 rpm for
more than 10seconds
after c oming uptospeed. Motor
wiring h arness
andfan coil c ontrol are operating
properly,
donot r eplace.
2.Check tobesure that the blower wheel isnot r ubbing the
housing.
3.Check motor tobesure t hat t he motor shaft isnotseized
(motor control module nmst beremoved and electronics
disconnected
fromwindings t o perform this check
properly).
4.Check m otor windings section following i nstructions
in
Section C.Indoor Fan Motor Troubleshooting.
If all t hese checks are normal, the motor control module may n eed
replacement.
STATUS
(;ODE 16, S YSTEM COMMUNICATION
FAULT
If,atany time, system c ommunications
are notsuccessful
fora
period e xceeding
2minutes, the fan coil c ontrol willonly allow
emergency
heating o r cooling operation using a common
thermostat,
and the terminal strip connections
and will display
Status code 16 on the amberSTATUS LED (see
Non-Communicating
Emergency
Cooling/Heating
Mode). No
further unit t roubleshooting
information
willbeavailable
atthe UI
until communications
are re-established.
Check system wiring t obe sure t he UIispowered
and connections
are made AtoA,BtoB, e tc.. and wiring i snot s horted.
Mis-wiring
orshorting ofthe ABCD communications
wiring willnot a llow
successful
communications.
Correcting
wiring faults willclear the
code a nd re-establish
communications.
Shorting
or mis-wiring the low voltage system
wiring w illnot cause
damage
tounit c ontrol ortoUIbut m ay c ause the lowvoltage fuse
toopen.
STATUS CODE 4 6, B ROWNOUT
CONDITION
If the secondary
voltage ofthe transformer
falls below 15-vac for
aperiod exceeding
4seconds,
Status (;ode 4 6willbedisplayed
on
STATUS
LED and the UIwillcommand
the control board t oturn
offcompressor.
When s econdary
voltage r ises a bove 1 7-vac f ormore than 4
seconds,
the brownout condition is cleared and normal system
operation will resume subject to anyminimum compressor
off-delay function which m ay b eineffect. Brownout
does not affect
blower orelectric heater operation.
STATUS
(;ODE 5 3, OUTDOOR
AIR TEMPERATURE
SENSOR
FAULT
Ifan OAT sensor isfound a tpower-up,
input isconstantly
checked
tobe within a valid temperature
range. If sensor isfound tobe open
orshorted atany t ime after initial validation,
Status Code 53will b e
displayed
atamber STATUS
LED.
Check forfaults i nwiring connecting
sensor toOAT terminals.
Using a n Ohm meter, check resistance
ofthermistor
forashort or
open c ondition.
If thermistor
isshorted oropen, replace ittoreturn t he system t o
normal operation.
If fault isinthe wiring c onnections,
correcting
the
fault willclear the code a nd return the system t onormal operation.
NOTE: Iffault condition isan open t hermistor
orawiring p roblem
that a ppears
tobean open t hermistor
and the power tothe unit i s
cycled off, t he fault c ode willbecleared onthe next power-up but
the fault willremain and system operation
willnot b eas expected.
This
is because on power-
up, the unit control cannot discern the
difference
between
an open sensor or ifa sensor is not installed.
F.
HP/AC
Control
Troubleshooting
See
Table
3
for
HP/AC
control
board
status
codes
and
troubleshooting
information.
Step 2--Sequence
of Operation
The 50DU packaged
air conditioner
is designed
for installation
with
a communicating
UI. This
unit will not respond
to commands
provided
by a common
thermostat
except under certain emergency
situations
described
in Step 1--Start-Up.
The UI uses temperature,
humidity
and other data supplied
from
indoor
and
outdoor
system
components
to control
heating
or
cooling system
for optimum
comfort.
The unit will be commanded
by UI to supply
airflow.
The unit will operate
the indoor
fan at
requested
airflow for most modes.
The nominal
requested
airflow will be 350 cfm per ton of nominal
cooling capacity
as defined by unit size. Actual airflow request will
be adjusted
from nominal
using indoor
and outdoor
temperature
and indoor
humidity
data to optimize
the system
operation
for
occupant
comfort
and system
efficiency.
Refer to UI literature
for
further system control
details.
Airflow
during
electric
heater
operation
must
be greater
than a
minimum
level for safe operation.
If UI instructs
unit
to turn on
electric heat and the requested
airflow is less than the minimum
level
the fan coil control will override
requested
value.
NOTE:
Once the compressor
has started and then has stopped,
it
should
not be started
again
until 4 minutes
have
elapsed.
The
cooling
cycle remains
"on"
until the room temperature
drops
to
point that is slightly below
the cooling
control setting of the UI.
16
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