WattMaster Water Source Heat Pump, Installation & Operation Manual

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WattMaster WHP Section 4
4-40 Start-Up and Troubleshooting
5.4.5 Comm Driver Chip Replacement
LOOP CONTROLLER CPU BOARD
COMM DRIVER CHIP
( U1 ) PIN 1
COMMLINK II
COMMUNICATIONS
DRIVER CHIP
WHP CONTROLLER MINILINK COMMUNICATIONS INTERFACE
PIN 1
WHP CONTROLLER
COMM DRIVER CHIP
( U5 )
WARNING!
USE EXTREME CAUTION WHEN REMOVING ANY CHIPS
TO AVOID DAMAGING ANY CIRCUIT BOARD TRACES WHICH
ARE UNDER THE CHIP.
BE SURE THAT ANY SMALL SCREWDRIVER OR OTHER
SHARP OBJECT USED TO REMOVE THE CHIP DOES NOT
COME INTO CONTACT WITH THE PRINTED CIRCUIT BOARD
SURFACE.
A SMALL SCREWDRIVER MAY BE INSERTED BETWEEN THE
CHIP AND THE SOCKET TO AID IN REMOVAL OF THE CHIP.
BE VERY CAREFUL NOT TO INSERT THE SCREWDRIVER UNDER
THE SOCKET!! DAMAGE TO THE BOARD IS NOT COVERED
BY WARRANTY.
TYPICAL RS-485
DRIVER CHIP
PIN 1
DOT
SOCKET
PRINTED
CIRCUIT
BOARD
LO
O
P
32
16
8
4
1
2
N
E
T
W
ORK
NETWORK LOOP
COMMUNICATIONS
DRIVER CHIP
(U5)
LOCAL LOOP
COMMUNICATIONS
DRIVER CHIP
(U8)
T
SH
R
24VAC
GND
T
SH
R
PIN 1
System Manager
Comm Driver Chip
(U13) Pin 1
U12
R1
0
Cx
9
1
EP
R
O
M
Cx
1
3
U9
U13
CX7
PAL
U8
CX
8
RN1
C2
C1
EW
D
O
G
U7
X1
X2
C3
U3
CX5
R3
Ys101806 REV.2
MODULAR
SYSTEM MANAGER
R4
R1
U1
U6
Cx
1
2
SC1
R13
C5
U1
0
CX
3
CX4
CX6
R9 D3
U4
PJ1
U2
CX
2
R2 R3
U3
D1
D2
R5
R6
DSPY1
P3
R7
RV1
Figure 4-11: Comm Driver Chip Replacement