U.S. Boiler Company X-203 Installation, Operating And Service Manual - page 27
27
X. Troubleshooting
A.
BEFORE TROUBLESHOOTING
The following pages contain trouble shooting tables for
use in diagnosing control problems. When using these
tables the following should be kept in mind:
1. This information is only meant to be used by
a professional heating technician as an aid in
diagnosing boiler problems.
2. In general, these tables assume that there are no
loose or miswired electrical connections. Before
using these tables inspect all electrical connections
on the boiler to make sure that they are tight. Also,
check the wiring on the boiler against the wiring
diagram in Figures 8 and 9. Ensure that incoming
120 Vac power polarity is correct and that the boiler
is properly grounded. Further, ensure that the control
power supply is 24 VAC (minimum 18 VAC to
maximum 30 VAC) and polarity is correct.
4. All controls on the X-2 Series are tested at least
once in the manufacturing process and a defective
control or component is generally the least likely
cause. Before replacing a component, try to rule out
all other possible causes.
5. When checking voltage across wiring harness pins
be careful not to insert the meter probes into the
pins. Doing so may damage the pin, resulting in a
loose connection when the harness is reconnected.
Press “I” key on the control to change
from one parameter to the next. Each
setting will alternate between display
code (for example
STA
) and value.
When
Err
(error) is shown:
Value
Description
4
Flame current lower than threshold
6
Flame Out of Normal Sequence
18
Electronics Failure
23
Flame Sensed During Pre-purge
32
Temperature Sensor Failure
55
Damper Failed to Open
56
Damper Failed to Close
57
Flame Rod Shorted to Ground
58
AC Line Frequency
59
Line Voltage Error
60
Thermostat input higher than threshold
61
Line Voltage Unstable
63
Soft Lockout – Recycles Exceeded
64
Soft Lockout – Internal Failure
Possible
STA
(status) values:
Figure 27: Using Control Display to Troubleshoot
Value
Description
1
Standby
4
Pre-purge
6
Spark
7
Flame Proving
8
Running
10
Retry/Recycle Delay
13
Soft Lockout
14
Hard Lockout
15
Waiting for Limit to Close
16
Flame Present Out of Sequence
17
Self Test
18
Waiting for Damper to Open
19
Waiting for Damper to Close
20
Damper Failure to Open
21
Damper Failure to Close