Table 35 — Illegal Configurations Recognized
by PSIO-1
CODE
NUMBER
ILLEGAL CONFIGURATION
DESCRIPTION
1
Incorrect Check Sum in configuration code
(factory or service code)
2 Unit type outside range of (1-3)
3
Number of compressors in a circuit outside the
range of 0-2
4
Air cooled chiller with a fan type outside the
range of 1-16
5
Air cooled chiller with Low Temperature Brine
fluid
6
Water cooled chiller configured for air cooled
head pressure
7
Selecting both OAT and Space Temp sensors
for External Reset operation
8 Air cooled chiller with condenser water pump
9 Air cooled chiller with condenser thermistors
10
MOP Set point is outside the range of
40 - 55 F (4.4 - 12.8 C)
11
Maximum Condensing Temperature Set point
(MCT
_
SP) is outside the range of 0 - 158 F
(-17.8 - 70 C)
LEGEND
MOP — Minimum Operating Temperature
OAT — Outdoor-Air Temperature
EXD Troubleshooting Procedure — Follow steps
below to diagnose and correct EXV/Economizer problems.
On 30HX units with economizers, verify that the valve
for the bubbler tube (bottom of economizer) is open. Check
EXV motor operation first. Press on the HSIO II
keypad and select the appropriate EXV. Press to
move the valve to 25%. You should be able to feel the ac-
tuator moving by placing your hand on the EXV or econo-
mizer body (the actuator is located about one-half to two-
thirds of the way up from the bottom of the economizer shell).
Press three more times until the display reads 100%
for a Target Percent (waiting until actuator stops each time).
A hard knocking should be felt from the actuator when
it reaches the top of its stroke (can be heard if
surroundings are relatively quiet). Press again if
necessary to confirm this. Press four times to step
the actuator closed in 25% increments, waiting again in be-
tween each move. The actuator should knock when it reaches
the bottom of its stroke. If it is believed that the valve is not
working properly, continue with the checkout procedure
below:
Check the EXV output signals at appropriate terminals
on EXV driver module (see Fig. 12). Connect positive test
lead to terminal 1 on the EXV driver for Circuit A and to
terminal 7 for Circuit B. Set meter for approximately 20 vdc.
Enter Valves and Motor Master test subfunction by pressing
on the HSIO. The EXV for Circuit A will be dis-
played; if desired, press the down arrow key for Circuit B.
When at the desired valve, press . The display should
change to show a Target Percent of 25%. The driver should
drive the circuit EXV under test. During the next several sec-
onds, connect negative test lead to pins 2, 3, 4, and 5 in suc-
cession (pins 8, 9, 10 and 11 for Circuit B). Voltage should
rise and fall at each pin. If it remains constant at a voltage
or shows 0 volts, remove the connector to the valve and
recheck.
Press to close the circuit EXV. Check the DSIO
address setting (the address should be 50). If a problem still
exists, replace the EXV driver module. If the voltage read-
ing is correct, the expansion valve and EXV wiring should
be checked. Check the EXV terminal strip and interconnect-
ing wiring.
1. Check color coding and wire connections. Make sure they
are connected to the correct terminals at the EXV driver
and EXV plug and that the cables are not crossed.
2. Check for continuity and tight connection at all pin
terminals.
Check the resistance of the EXV motor windings.
Remove the DSIO-EXV plug J4 terminal strip and check the
resistance between the common lead (red wire, terminal D)
and remaining leads, A, B, C, and E (see Fig. 12). The re-
sistance should be 25 ohms ± 2 ohms.
RED
GRN
WHT
BLK
BRN
D
C
E
B
A
RED
GRN
WHT
BLK
BRN
D
C
E
B
A
EXV-A
EXV-B
7
2
1
1
2
3
4
5
8
9
10
11
EXV DRIVER BOARD, J4
EXV — Electronic Expansion
Valve
Fig. 12 — EXV Cable Connections to EXV Driver Module, DSIO-EXV
50
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