18-BB38D1-1D-EN
21
Figure 15.
ECM Fan Control
CFM
SELECTION
LIGHT
DIP
SWITCHES
D
De
em
ma
an
nd
d D
De
effrro
osstt O
Op
pe
erra
attiio
on
n
During the heating cycle, the outdoor coil may require
a defrost cycle which is determined by the demand
defrost control ((D
DF
FC
C)). This control continuously
measures the outdoor coil temperature ((C
CB
BS
S)) and the
outdoor ambient temperature ((O
OD
DS
S--B
B)) and calculates
the difference or delta-T measurement. When the
calculated delta-T is met, the demand defrost control
((D
DF
FC
C)) opens the circuit to the outdoor fan motor
((O
OD
DM
M)) and energizes the switch-over valve ((S
SO
OV
V)),
placing the unit in the cooling mode to defrost the
outdoor coil. The outdoor coil temperature sensor
((C
CB
BS
S)) terminates the defrost cycle, or times out after
fifteen minutes in defrost, the ((D
DF
FC
C)) energizes the
outdoor fan motor ((O
OD
DM
M)) and twelve seconds later de-
energizes the ((S
SO
OV
V)), which returns the unit to the
heating mode. Supplementary electric heat, if
provided, is brought on to control indoor temperature
during the defrost cycle.
F
Fiin
na
all IIn
nsstta
alllla
attiio
on
n C
Ch
he
ecckklliisstt
IIm
mp
po
orrtta
an
ntt:: Perform a final unit inspection to be sure
that factory tubing has not shifted during
shipment. Adjust tubing if necessary so
tubes do not rub against each other when
the unit runs. Also be sure that wiring
connections are tight and properly secured.
☐
Does the unit run and operate as described in the
Sequence of Operation section in response to the
room thermostat?
☐
Are the condenser fan and indoor blower operating
correctly with proper rotation and without undue
noise?
☐
Is the compressor operating correctly and has the
system been checked with a charging chart?
☐
Has the voltage and running current been checked
to determine if it is within limits?
☐
Has the thermostat been checked for calibration
and the air discharge grills adjusted to balance the
system?
☐
Has the ductwork been checked for air leaks and
condensation?
☐
Has the heating air temperature rise been checked?
☐
Has the unit been checked for tubing and sheet
metal rattles? Are there any other unusual noises to
be checked?
☐
Are all covers and panels in place and properly
fastened?
☐
Has the owner been instructed on the proper
operation and maintenance of the unit? Be sure to
leave this manual with the owner.
Maintenance
O
Ow
wn
ne
err M
Ma
aiin
ntte
en
na
an
ncce
e
Some of the periodic maintenance functions of the unit
can be performed by the owner; this includes replacing
the disposable or cleaning the permanent air filters,
cleaning the unit cabinet, cleaning the condenser coil,
and conducting a general unit inspection on a regular
basis.
F
Fiilltte
errss
When the system is in constant operation, inspect the
filters at least once each month.
If the unit has disposable-type filters, replace them with
new filters of the same type and size. D
Do
o n
no
ott a
atttte
em
mp
ptt
tto
o cclle
ea
an
n d
diissp
po
ossa
ab
blle
e ffiilltte
errss..
Permanent-type filters can be cleaned by washing them
with a mild detergent and water. Make sure that the
filters are thoroughly dry before reinstalling them in
the unit (or duct system).
N
No
otte
e:: It may be necessary to replace permanent filters
annually if washing fails to clean the filter or if
the filter shows signs of deterioration. Be sure to
use the same type and size as was originally
installed.
C
Co
on
nd
de
en
nsse
err C
Co
oiill
Be sure to keep all vegetation and debris away from the
condenser coil area.
