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XV.
TROUBLESHOOTING GUIDE FOR UNIT OPERATION
Blown
Fuse/Tripped
Circuit
Breaker
Replace fuse or
reset
circuit
breaker. (Check
for
correct
size
fuse
or
circuit
breaker.)
Blown
Fuse
on
Controller
Replace fuse on
controller.
(Check
for
correct
size
fuse.)
Broken
or
l,oose
Wires
Replace or tighten the wires.
Voltage
Supply
Low
If
voltage is
below minimum
voltage on
data
plate, contact
local
power company
Low Voltage
Circuit
Check
24-volt
ffansformer
for
burnout,
blown
fuse
or
voltage
less
than
l8
volts.
Remote
Hydronic Control or
Room Thermostat
Set system
to
"Cool"
and
lowest temperature setting,
unit
should run.
Set
system
to "Heat"
and
highest temperature setting,
unit
should run.
If
unit
does
not run
in
either
case,
the
hydronic control
(or room thermostat)
could
be
faulty or
incorrectly wired. To
prove
faulty
or
miswired,
disconnect thermostat wires
at the
unit
and
jumper
between
'R",
'Y'
and
"G" terminals,
and
unit
should run.
Only
replace
with
correct replacement.
A
substitute may not
work properly.
Interruptible
Power
Check
incoming
supply voltage.
Entire unit
does
not
run.
Water
Lack of sufficient
pressure.
flow.
temperature and/or
quantity of
water.
Unit
Undersized
Recalculate heat gains
or
losses
for
space
to
be
conditioned.
If
excessive,
rectify
by
adding
insulation,
shading,
etc.
Check
for
leaks
in
ductwork
or
introduction of
ambient air
throush
doors
and
windows.
Loss of
Conditioned
Air
by
Leaks
Thermostat
Improperly
located thermostat
(e.9. near
kitchen
sensing inaccurately the
comfon
level in
living
areas).
Check
anticipator
setting (Should
be
i.0 or
1.2).
Airflow
(Across
fan
coil)
Lack of
adequate
airflow
or improper distribution of
air. Check the
motor
speed
and duct
sizing.
Check the
filter, it
should
be
inspected every
month
and
changed
if
dirry.
Remove
or
add
resistance accordingly.
Refri_eerant
Char-ee
Low
on
refrigerant
charge causing
inefficient
operation.
Adjust only after
checking
CFM, GPM
and
inlet/outlet
temperatures.
Compressor
Check
for
defective compressor.
If
discharge
pressure
is too
low
and suction
Dressure
too
hieh.
comDressor
is
not
pumping
prooerlv.
Reolace
comDressor.
Reversing
Valve
Defective reversing
valve
creating
bypass
of refrigerant from
discharge to suction
side
of
compressor. When
it
is necessary
to replace the reversing valve, wrap
it
with
a
wet
cloth
and
direct
the
heat away. Excessive heat
can damage
the valve.
Insufficient cooling or
heating
Desuperheater
The desuperheater
circuit
(in-line
fuse) shouid be disconnected
during cold
weather to
a1low
fuIl
heating load to
house.
Remote
Hydronic Control or
Room Thermostat
Check setting
and
wiring.
If
thermostat
has an
anticipator,
set
it
at
1
.0
or
1.2.
Wiring
Check
for
loose or broken wires
at
compressor, capacitor, or contactor
Biown
Fuse
Replace fuse or
reset
circuit breaker.
(Check
for
corect
size
fuse
or circuit
breaker.)
High or Low
Pressure
Controls
The
unit
could be
off
on the high
or
low-pressure cutout
control.
Check water
GPM
and
temperatures, ambient temperature
and
loss
of
refrigerant.
If
unit
still
fails
to run, check
for faulty
pressure
controls
individually.
Replace
if
defective.
Defective
Capacitor
Check capacitor,
if
defective remove, replace.
and
rewire
correctly.
Voltage
Supply
Low
Ifvoltage
is
below minimum
voltage specified on the
data
plate. contact local
power company. Check voltage at compressor
forpossible
open
terminal.
Low
Voltase Circuit
Check
24-volt
transformer
for burn
out
or
voltage
less
that
l8
volts.
With
a
voltmeter,
check signal
from tlermostat
at
Y
to
X,
M
I
on
controller
to
X,
capacitor voitage drop. Replace component that
does
not energize.
Compressor Overload
Open
In
all
cases
an
"internal"
compressor overload is
used.
Ifthe
compressor motor is
too
hot,
the overload
will
not
reset
until
the
compressor cools down.
If
the
compressor is
cool
and
the overload
does
not
reset,
there may be
a
defective
or
open overload. Replace the compressor.
Compressor
Motor
Shorted to
Ground
Internal
winding
grounded to
the
compressor shell.
Replace
the compressor.
If
compressor burnout replace the
liquid line fllter/drier.
Compressor
Windin_es
Open
Check
continuity of
the compressor
windings
with
an
ohmmeter.
If
the
windings
are
open, replace the compressor.
Hydronic
pump runs
but
compressor
does
not,
or
compressor
short cycles.
Seized
Compressor
Try
an
auxiliary
capacitor
in parallel
with
the
run capacitor
momentarily.
If
the
compressor
still
does
not
start,
replace
it.
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?ROBLAE{
POSSIBLE CAUS$
C}IECKS
A
ND
COB"RECI'IONS
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