HTP MODCON1000 - Page 52

LP-428 Rev. 6.6.16
52
SUPPLY SENSOR F02
PUMP ON
F02 indicates the supply temperature sensor
of the boiler has failed. The boiler will not
restart until a technician replaces the sensor
and pushes RESET on the display. This is
a serious safety issue as indicated by the
illuminated red light and the word LOCKOUT
ashing on the display. During this lockout
fault, the pump will be on.
1. Check the electrical connection to the thermistor on the outlet
manifold. Verify 5 VDC by checking the Molex connector. If
there is no 5 VDC, check the harness. If harness is OK, replace
the control. Verify thermistor values by referencing chart in this
manual.
2. Replace thermistor if necessary.
NOTE: The boiler will reset automatically once the fault is
corrected.
RETURN SENSOR F03
PUMP ON
F03 indicates the return temperature sensor
of the boiler has failed. The boiler will not
restart until a technician replaces the sensor
and pushes RESET on the display. This is
a serious safety issue as indicated by the
illuminated red light and the word LOCKOUT
ashing on the display. During this lockout
fault, the pump will be on.
1. Check circulator pump operation.
2. Ensure adequate ow through the boiler by accessing the
status menu and determining there is less than a 50
o
F rise from
the return thermistor to the supply thermistor.
3. Troubleshoot thermistor by following the steps in F02.
FLUE SENSOR F04
PUMP ON
F04 indicates that the ue temperature
sensor of the boiler has failed. The boiler will
not restart until a technician replaces the
sensor and pushes RESET on the display. This
is a serious safety issue as indicated by the
illuminated red light and the word LOCKOUT
ashing on the display. During this lockout
fault, the pump will be on.
Inspect the ue sensor for physical damage or corrosion and
replace it if necessary. Check the electrical connection to the ue
sensor and repair as necessary. Measure the resistance of the
sensor and refer to the sensor resistance table in this manual. The
temperature on the chart should be close to the temperature in
the ue. If not, replace the ue sensor.
Screen Description Possible Remedy
SUPPLY TEMP HIGH F05
PUMP ON
F05 indicates the boiler supply temperature
is excessive. When accompanied by the
red FAULT light and LOCKOUT ashing on
the display, this code indicates the supply
sensor temperature has exceeded 230
o
F and
a serious safety issue exists. The boiler will
not restart until a technician determines and
repairs the cause of excessive temperature
and pushes RESET on the display.
If the FAULT light is not illuminated and
this message is displayed, the supply tem-
perature of the boiler is at or above 210
o
F.
The message will clear automatically when
the temperature drops below 194
o
F. During
the time that this fault is displayed, the pump
will be on.
1. Check circulator pump operation.
2. Ensure adequate ow through the boiler by accessing the
status menu and determining there is less than a 50°F rise from
the return thermistor to the supply thermistor.
3. Check the direction of ow o the boiler circulator. (See Piping
Details in this manual.)
4. Troubleshoot the thermistor by following steps in F02.
RETURN TEMP HIGH F06
PUMP ON
This display indicates that the boiler
return temperature is excessive. When
accompanied by the red FAULT light and
LOCKOUT ashing on the display, this code
indicates that the return sensor temperature
has exceeded 230
o
F and a serious safety
issue exists. The boiler will not restart until a
technician determines and repairs the cause
of excessive temperature and pushes RESET
on the display.
If the red FAULT light is not illuminated and
this message is displayed, then the return
temperature of the boiler is at or above
210
o
F. The message will clear automatically
when the temperature drops below 194
o
F.
During the time that this message or lockout
fault is displayed, the pump will be on.
1. Check circulator pump operation.
2. Ensure adequate ow through the boiler by accessing the
status menu and determining there is less than a 50°F rise from
the return thermistor to the supply thermistor.
3. Check the direction of ow on boiler circulator. (See Piping
Details in this manual.)
4. Troubleshoot thermistor by following steps in F02.