Crown Boiler PHNTM080 - Page 116

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a) Soft Lockout-Asoftlockoutpreventstheboilerfromringuntiltheproblemhasbeencorrectedand,insomecases,a
speciedamountoftime(upto1hour,dependingonthenatureofthefault)haspassed.AnexampleoftheFaultMenu
structure during a soft lockout is shown in Figure 14.0
b) Hard Lockout-AhardlockoutpreventstheboilerfromringuntiltheproblemhasbeencorrectedANDtheboilerhas
been manually reset. This can either be done at the boiler control itself or on the hard lockout screen. An example of the
Fault Menu structure during a hard lockout is shown in Figure 14.2.
A hard lockout closes the alarm contact connections on the low voltage PCB.
c) Sensors - The Sensor Screens show the status of all sensors. Possible states of the sensors include:
• None - The boiler control (R7910B) is not looking for an input from this sensor
• Normal - The sensor is working normally
• Shorted - There is a short between the boiler control (R7910B) and the sensor or the sensor is defective
• Open - There is a break in the wiring between the boiler control (R7910B) and the sensor or the sensor is defective
• Out of Range - The sensor is defective or is being subjected to electrical noise.
• Unreliable - The sensor is defective or is being subjected to electrical noise.
d) Limit Status - The Limit Status Screen shows the status of all safety limits. Each of these limits is either shown as being
ON or OFF. It is important to remember that since all of limits are wired in series, any limit which is in the OFF state
will cause all limits “downstream” of it to also appear on this screen as being OFF, regardless of whether or not they
actually are. The limits are wired in the following order (also see Figure 10.5):
1. External Limits, including LWCO if used.
2. Air Proving Switch (APS)
3. Sump Pressure Switch
4. Flow Switch
Therefore, in the example shown in Figure 14.1, the Auxiliary limit is known to be closed, the LWCO is known to be
open, and the High Limit and Air Pressure switches could be either open or closed.
B. Troubleshooting when the Display is Blank
UsetheowchartinFigure14.3tolocatetheproblemwhenthedisplayisblankorisnotreadable.
C. Operation and Troubleshooting of Boiler Controls Other than the Sola
For the location of the controls described below, see Figure 14.4.
Fuses – This boiler is equipped with two 5 x 20mm fuses:
 • Pump Fuse – This fuse protects the relay contacts in the boiler control from excessive current draw caused by an
oversized or seized pump. The fuse supplied with the boiler is a 6.3A, slow blow type. A replacement fuse is supplied
with the boiler. If this fuse blows, look for a seized pump, a short circuit in the pump wiring, or an oversized DHW or
system pump. When a Taco 0013 is supplied for the boiler pump, the total draw of the DHW and system pumps cannot
exceed 4.3A.
 • 24V Fuse – This fuse protects the transformer from excessive draw and is a 1.6A slow blow type. If this fuse blows, look
  forashortcircuitinthe24Vwiringbeforereplacing.Ashortcircuittogroundineldwiring(suchasathermostatwire
touching a pipe) will cause this fuse to blow. A replacement fuse is supplied with the boiler