Troubleshooting; Technical Specifications - Johnson Controls FT-04A Quick Start Manual

Troubleshooting

Table 3: Troubleshooting
Problem
The controller does not
turn on due to one of the
following problems:
• The transformer
trips. Power is at the
transformer primary
and there is no voltage
at the secondary.
• The breaker or fuse
trips. Power is at
transformer primary.
You find 24 V at
secondary and 0 V at
breaker or fuse.
Analog output mode is
invalid. 0 V to 10 V output
is set to 100%, but output
terminals are less than 10 V.
Analog mode for a
configurable output is
invalid. For example, 0 V to
10 V output results in an
unwanted offset of up to 1 V.
The Common Reference is
incorrect.

Technical specifications

Table 4: FT-04A UL input, output, and communication ratings
Specification Description
Power supply • 24 VAC, ± 5%
• 24 VDC, + 20% or - 15%
2.5 VA, Class 2
Universal Voltage
inputs
Resistance
Analog output Voltage
Minimum load impedance
Maximum current draw
Cause
The transformer shorted.
The 24 VAC powered sensor is not
wired with the same polarity as the
controller.
Load impedance is lower than 2k
ohms.
The COM terminal is not
connected.
0 VDC to 10 VDC, Class 2
3k to 50k Ohm
0 V to 10 V, Class 2
2k ohm
5 mA
Solution
1. Ensure that the polarity of ~24 V COM on the
controller, auxiliary devices, and input and
output devices is the same.
2. Verify that the short circuit is resolved with an
ohm-meter.
3. Reset the breaker or fuse, or replace the
transformer.
Note: If you replace the transformer,
replace it with a model that uses a reset-
table circuit breaker. A circuit breaker
makes it easier to solve wiring problems.
4. To verify the connection, complete the following
steps:
a. Disconnect the secondary of the 24 VAC
transformer.
b. Use an ohm-meter to measure between ~24
V H and G at the controller. Ensure that no
short circuit occurs.
Note: If your installation requires that
you earth ground the transformer sec-
ondary, verify that the earth ground
connection is valid and not shared
between multiple pieces of equipment.
1. Ensure that the voltage control device load
impedance is higher than 2k ohms. For
more information, refer to voltage device
manufacturer specification.
2. Disconnect the connected device and verify that
the value you require is present.
1. Connect the COM terminal of the configurable
output to the common of the connected end
device.
2. Measure the output and verify that it matches
the command.
3. Disconnect the connected device and verify the
commanded value is present.
3% accuracy
3% accuracy
FT-04A Quick Start Guide
Terminal
H and G
UI1, UI2 and
COM
AO1, AO2 and
COM
7