Fulton Hopkins (HPN) Horizontal Coil Thermal Fluid (hot oil) Heater - Manual (Page 76)

© The Fulton Companies
MAINTENANCE
HPN-IOM-2014-0416
SECTION 4
4-16
TABLE 10-N - PILOT FLAME FAILURE TROUBLESHOOTING
Problem Potential Remedy
Pilot fl ame strength is
inadequate Cycle the unit. During the pilot trial for ignition, carefully observe the pilot fl ame strength.
On Honeywell controllers, the pilot fl ame strength must be between 1.25 to 5.0 VDC. On Fireye controllers, the pilot fl ame strength
must be greater than 10 VDC.
Current controls are supplied with a test switch that can hold the programmer in the pilot trial for ignition stage. If a pilot signal
greater that 0.0 but less than the minimum required is detected, look through the sight hole provided on the burner plate of the
heater to visibly detect fl ame. If fl ame is seen, make small adjustments to increase pilot gas and air to provide larger fl ame.
Pilot sensing device does not
work properly Cycle the unit. If a pilot signal of 0.0 is detected, look through the sight hole provided on the burner plate of the heater to visibly
detect fl ame.
If fl ame is seen, your fl ame detection device or amplifi er may be faulty. If the unit has a fl ame rod, lockout and tag heater’s electrical
circuit and fuel supply. Pull pilot assembly out of unit. Inspect the fl ame rod. If the fl ame rod is corroded, shows signs of heat
impingement, has been turned off or has cracks in the porcelain, replace with a new fl ame rod.
Reinstall and cycle unit. If the unit has a U.V. scanner, lockout and tag heater’s fuel supply. Remove U.V. scanner from U.V. sight tube.
Make sure that the lens of the scanner is clean. Use a lighter or match and make a fl ame in front of the scanner eye. Lens should
fl icker. If unit does not fl icker, change U.V. scanner. If this change does not work, change U.V. amplifi er. Reinstall and cycle unit.
Room air pressure is diff erent
from outside air pressure Check room air pressure relative to outside air pressure. Heater room pressure should equal outside air pressure. Signifi cant
diff erences in pressure will result in an erratic fl ame, which will not deliver a strong fl ame signal.
TABLE 10-O - MAIN FLAME FAILURE TROUBLESHOOTING
Problem Potential Remedy
Main fl ame strength is
inadequate Cycle the unit. During the main fl ame proving period , carefully observe the pilot fl ame strength. Current controls are supplied with a
test switch that can hold the programmer in the main fl ame proving period.
If a main signal is greater than 0.0 but less than the minimum required is detected, look through the observation port to try to visibly
see fl ame. A combustion change may be necessary to establish main.
If observed fl ame is blue, slightly decrease the air damper setting and recycle. If fl ame is red or orange, slightly increase air damper
setting and recycle. Once adequate fl ame signal is established, reset input and combustion throughout range of modulation.
Flame sensing device does not
work properly Cycle the unit. If a signal of 0.0 is detected, look through the sight hole provided on the burner plate of the heater to visibly detect
fl ame. If fl ame is seen, your fl ame detection device or amplifi er may be faulty.
If the unit has a fl ame rod, lockout and tag heater’s electrical circuit and fuel supply. Pull pilot assembly out of unit. Inspect the fl ame
rod. If the fl ame rod is corroded, shows signs of heat impingement, has been burned off or has cracks in the porcelain, replace with a
new fl ame rod. Reinstall and cycle unit.
If the unit has a U.V. scanner, lockout and tag heater’s fuel supply. Remove U.V. scanner from U.V. sight tube Make sure that the lens
of the scanner is clean. Use a lighter or match and make a fl ame in front of the scanner eye. Lens should fl icker. If unit does not fl icker,
change U.V. scanner. If this change does not work, change U.V. amplifi er. Reinstall and cycle unit.
Room air pressure is diff erent
from outside air pressure Check room air pressure relative to outside air pressure. Heater room pressure should equal outside air pressure. Signifi cant
diff erences in pressure will result in an erratic fl ame, which will not deliver a strong fl ame signal.
Unit is experiencing too great
of a restriction At the breaching of the heater, take a draft reading. Draft should read between -.02” w.c. and -.04” w.c. with the heater off and
between -.04” w.c. and -.08” w.c. with the unit on. A restrictive draft would be a draft that was positive. A restrictive draft is usually
the result a stack that is undersized, a stack with too many elbows or a stack whose cap or piping is warped and damaged. Another
source of restriction results from broken refractory. If the unit’s refractory breaks, large enough pieces could block the fl ue passes.
The burner should be pulled for refractory inspection. A broken refractory should be cleaned out and replaced.