Service Manual

SERVICE AND MAINTENANCE FAN COILS
4 496 08 8001 02
Specifications subject to change without notice.
IF TRACES ARE OVERHEATED ON BACK OF PCB:
Usually whenever a trace is blown on PCB, it means either
there has been a high−voltage short or high voltage has been
applied to low−voltage circuit. This can be prevented by
making sure PCB is wired correctly before PCB has power
applied to it.
C. If Transformer Fuse Keeps Blowing:
When low−voltage fuse blows, it means transformer would
have blown if fuse had not been in circuit to protect it. The fuse
usually blows when there is a high current draw on
transformer, high voltage applied to low−voltage circuit, or a
direct secondary short. When there is a high current draw on
transformer, it is most likely because transformer has been
shorted or system is trying to draw more VA than transformer
rating allows. When fuse blows because of high voltage, the
system has mixed high− and low−voltage signals.
1. Check wiring of sequencers/relays as shown in
Figure 1. Be sure transformer is not shorting out
because thermostat wires are miswired.
2. Check wiring of relays as shown in Figure 1. Be sure
low−voltage and high−voltage wiring is correct.
3. Check VA draw on transformer. If VA draw is more than
VA rating of transformer, fuse will blow. If this is the
case, replace transformer with one that has a higher VA
rating and meets system specifications.
D. If Fan Runs Continuously:
1. If PCB has no low−voltage power, check blue and black
fan leads. These may be switched at sequencer/relay.
2. If PCB has low−voltage power, check fan relay to see if
it is opening and closing. It may be stuck in the normally
closed position due to debris in relay.
E. Transformer Failure:
Check 208−V and 230−V transformer connections. They may
be miswired.
Figure 1 − Fan Coil Printed Circuit Board (contact FAST for part number)
®
®
CPC-E
94V-0
LR40061
HSCI
5 AMP
C
T
G
R
SPT
K1
U1
R7
R9
R10
C8
C7
R2
R3
C3
R6
R11
C4
C6
C5
R8
R5
R4
Q1
C1C2
F1
JW1
R1
Z1
D2
D1
NO
NC
FAN
RELAY
C
C
Representative drawing only. Please contact FAST for part number.
A03010
Figure 2 − Electric Heater Control Box
312753
T-O-D 60TX11
HH19ZA945
C9725
L145-55F
312753
T-O-D 60TX11
HH19ZA945
C9725
L145-55F
SPT
FAN
RELAY
NO
NC
5
PULL TO OPEN
WARNING
ELECTRIC SHOCK
HAZARD
DISCONNECT
REMOTE POWER
SUPPLY BEFORE
OPENING PANEL.
322861-101 REV. A
A13032