Troubleshooting
4.4
Functional check of the cooling system
To test the function of the cooling system you can use the following functions tables.
During program course use a multimeter to measure the output signal at the analog output
AA1
(pins 17 and
18) of the controller MB1 I/O-board (-
3N2
).
The clocking of the corresponding valves can be detected by the corresponding LED.
The values given under
X
indicate the start values. The values given under
W
indicate the target values to be
triggered. The target values must not be reached for the test, it is sufficient to watch them during the first five
minutes.
Humidity switch (-8S1) ON
Temperature / Humidity
Solenoid valve
(
-7Y1
),
Binary output
BA2
on controller MB1
I/O-board,
large
evaporator
Solenoid valve
(
-7Y2
),
Binary output
BA3
on controller MB1
I/O-board,
small
evaporator
Analog output
AA1
on
controller MB1 I/O-
board, controller cooling
X:
Temperature: 20°C to 25°C
68°F to 75°F
Humidity: < 95 % r.H.
W:
Temperature: 10°C /
50°F
Humidity: 95 % r.H.
Clocking
on / off
2 / 15
seconds
Clocking
on / off
2 / 15
seconds
According to regulation
ratio of temperature
initially ≤ 5 V DC
gradually decreasing
if X=W then 0 V
X:
Temperature: 20°C to 25°C
68°F to 75°F
Humidity: 50 % r.H.
W:
Temperature: 10°C /
50°F
Humidity: 0 % r.H.
Clocking at least
1 minute
on / off
2 / 15
seconds
then completely “OFF”
Clocking
on / off
2 / 15
seconds
According to regulation
ratio of temperature and
humidity
initially ≤ 5 V DC
gradually decreasing
if X=W then 0 V
X:
Temperature: 20°C to 25°C
68°F to 122°F
Humidity: < 50 % r.H.
W:
Temperature: 50°C /
122°F
Humidity: 95 % r.H.
“OFF”
Clocking
on / off
2 / 15
seconds
near 0 V
See also chap. 10.5, “checking the step motor valve”.
Service Manual KBF (E5.2) 04-2015
25
