Fan User Manual

59
Table 36—Perfect Humidity Adaptive Dehumidification System Subcooling Mode Service Analysis
PROBLEM CAUSE REMEDY
Subcooling Mode (Liquid Re heat)
Will Not Energize.
No power to control transformer from
evaporator-fan motor.
Check power source and evaporator-fan relay. Ensure all
wire connections are tight.
W
i
l
l
N
o
t
E
n
e
r
g
i
z
e
.
No power from control transformer to liquid lin e
solenoid valve.
1. Fuse open; check fuse. Ensure continuity of wiring.
2. Low-pressure switch open. Cycle unit off and allow
low-pressure switch to reset. Replace switch if it will
not close.
3. Transformer bad; check transformer.
Liquid line solenoid valve will not operate. 1. Solenoid coil defective; replace.
2. Solenoid valve stuck open; replace.
Liquid line solenoid valve will not open. Valve is stuck closed; replace valve.
Low System Capacity. Low refrigerant charge or frosted evaporator coil. 1. Check charge amount. Charge per Fig. 53--- 56.
2. Evaporator coil frosted; check and replace low-pres-
sure switch if necessary .
Loss of Compressor Superhe at
Conditions with Subcooling/Reheat
Dehumidification Coil Energized.
Thermostatic expansion valve (TXV). 1. Check TXV bulb mounting, and secure tightly to suc-
tion line.
2. Replace TXV if stuck open or closed.
Table 37—Perfect Humidity Adaptive Dehumidification System Hot Gas Reheat Mode Service Analysis
PROBLEM CAUSE REMEDY
Reheat Mode Will Not Energize. No power to control transformer from
evaporator-fan motor.
Check power source and evaporator-fan relay. Ensure all
wire connections are tight.
No power from control transformer to hot gas
line solenoid valve
1. Fuse open; check fuse. Ensure continuity of wiring.
2. Low-pressure switch open. Cycle unit off and allow
low-pressure switch to reset. Replace switch if it will
not close.
3. Transformer bad; check transformer.
Hot gas line solenoid valve will not operate. 1. Solenoid coil defective; replace.
2. Solenoid valve stuck closed; replace.
Low refrigerant charge or frosted evaporator coil. 1. Check charge amount. Charge per Fig. 53---56.
2. Evaporator coil frosted; check and replace low-pres-
sure switch if necessary .
Loss of Compressor Superhe at
Conditions with Subcooling/Reheat
Dehumidification Coil Energized.
Thermostatic expansion valve (TXV). 1. Check TXV bulb mounting, and secure tightly to suc-
tion line.
2. Replace TXV if stuck open or closed.
Excessive Superh eat. Liquid line solenoid valve will not operate. Valve is stuck, replace valve.
E
x
c
e
s
s
i
v
e
S
u
p
e
r
h
e
a
t
.
Hot gas line solenoid valve will not close. Valve is stuck; replace valve.
Table 38—EconoMi$er IV Input/Output Logic
INPUTS OUTPUTS
D
e
m
a
n
d
C
o
n
t
r
o
l
Enthalpy* Compressor NTerminal†
D
eman
d
C
ontro
l
V
t
i
l
t
i
(
D
C
V
)
O
u
t
d
o
o
r
R
e
t
u
r
n
Y1 Y2
Stage Stage
Occupied Unoccupied
V
entilation (DC
V
)
O
ut
d
oor
R
eturn
Y
1
Y
2
1 2
Damper
Below set
(
D
C
V
L
E
D
O
f
f
)
High
(
F
C
l
i
L
E
D
O
f
f
)
Low
On On On On
Minimum position Closed
B
e
l
o
w
s
e
t
(DCV LED Off)
H
i
g
h
(F ree Cooling LED Off)
L
o
w
On Off On Off
M
i
n
i
m
u
m
p
o
s
i
t
i
o
n
C
l
o
s
e
d
Off Off Off Off
Low
(
F
C
l
i
L
E
D
O
)
High
On On On Off
Modulating** (between min.
i
i
d
f
l
l
)
Modulating** (between
l
d
d
f
l
l
)
L
o
w
(F ree Cooling LED On)
H
i
g
h
On Off Off Off
M
o
d
u
l
a
t
i
n
g
(
b
e
t
w
e
e
n
m
i
n
.
position and full-open)
M
o
d
u
l
a
t
i
n
g
(
b
e
t
w
e
e
n
closed and full-open)
Off Off Off Off Minimum position Closed
Above set
(
D
C
V
L
E
D
O
)
High
(
F
C
l
i
L
E
D
O
f
f
)
Low
On On On On
Modulating†† (between min.
i
i
d
D
C
V
i
)
Modulating†† (between
l
d
d
D
C
V
A
b
o
v
e
s
e
t
(DCV LED On)
H
i
g
h
(F ree Cooling LED Off)
L
o
w
On Off On Off
M
o
d
u
l
a
t
i
n
g
†
†
(
b
e
t
w
e
e
n
m
i
n
.
position and DCV maximum)
M
o
d
u
l
a
t
i
n
g
†
†
(
b
e
t
w
e
e
n
closed and DCV
m
a
x
i
m
u
m
)
Off Off Off Off
ma
x
imum)
Low
(
F
C
l
i
L
E
D
O
)
High
On On On Off
Modulating*** Modulating†††
L
o
w
(F ree Cooling LED On)
H
i
g
h
On Off Off Off
M
o
d
u
l
a
t
i
n
g
M
o
d
u
l
a
t
i
n
g
†
†
†
Off Off Off Off
*For single enthalpy control, the module compares outdoor enthalpy to the ABCD set point.
†Power at N terminal determines Occupied/Unoccupied setting: 24 vac (Occupied), no power (Unoccupied).
**Modulation is based on the supply-air sensor signal.
††Modulation is based on the D CV signal.
***Modulation is based on the greater of DCV and supply-air sensor signals, between minimum position and either maximum position (DCV) or fully open (sup-
ply-air signal).
†††Modulation is based on the greater of DCV and supply-air sensor signals, between closed and either maximum position (DCV) or fully open (supply-airsig-
nal).
551B,C