Fulton Hopkins (HPN) Horizontal Coil Thermal Fluid (hot oil) Heater - Manual (Page 71)

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SECTION 4
HPN-IOM-2014-0416
MAINTENANCE
4-11
controllers indicate a Pilot Flame Failure by showing as a fault
code either Fault 28 for Honeywell 7800 series controllers.
Flame Failure PTFI on Fireye E110 series controllers or Fault
9 on Fireye Nexus controls. For electro-mechanical controls,
you need to witness when the failure occurs. A Pilot Flame
Failure indicates that either a strong enough pilot fl ame
was not generated or the means of sensing the pilot fl ame
strength has failed. All gas fi red units have a gas pilot. Oil fi red
units may be 2-stage, in which the 1st stage to light would be
considered the pilot, or may have a gas pilot. In either case,
during the pilot proving period, the fl ame programmer must
sense a strong enough fl ame to initiate the opening of the
main valves.
 MAIN FLAME FAILURE
Main Flame Failure is a fl ame failure that occurs while the
unit is trying to establish an adequate fl ame signal during the
Main Flame Trial for Ignition.
Solid state controllers indicate a Main Flame Failure by
showing as a fault code of either Fault 19 for Honeywell
7800 series controllers, Flame Failure MTFI on Fireye E110
series controllers, or a Fault 09 for Fireye Nexus controls. For
electro-mechanical controls, you need to witness when the
failure occurs.
A Main Flame Failure indicates that either a strong enough
main fl ame was not generated or the means of sensing
the main fl ame strength has failed. During the main fl ame
proving period, the fl ame programmer must sense a strong
enough fl ame to hold the main valves open. If you are
experiencing Main Flame Failures, check the items indicated
in Table 10-O.
TABLE 10-A - LOW INLET PRESSURE SWITCH TROUBLESHOOTING
Problem Potential Remedy
Plugged circulation pump
strainer basket A plugged strainer will result in a decrease of fl ow through the heater. High vacuums developed from plugged strainers can also
stress the seals of the pump causing the pump to fail.
A “Pump Suction” gauge is provided on Fulton Thermal skids to help determine when a strainer needs cleaning. Generally this point
is between 0 and -5” Hg.
If the strainer is plugged, isolate the strainer and drain that section of piping being mindful of the temperature of the thermal fl uid.
Remove the strainer and clean with compressed air, high-pressure water or a cleaning solution. Replace and observe new pump
suction pressure.
Failed Circulation Pump
Coupling A failed coupling will result in a decreased or no fl ow condition through the heater. The coupling can be checked by removing the
coupling guard between the pump and pump motor.
The coupling should not be torn or misshapen. If the coupling needs to be replaced, it is recommended to re-align the circulating
pump fi rst at ambient temperature and again when it’s at operating temperature. Alignment should be within pump manufacturers’
specifi cations
Cavitation of the circulating
pump Cavitation occurs when a pump experiences a loss of head or if any low heater fl ashes to gas at the impeller. During this time, the
pump impeller spins without actually circulating any thermal fl uid.
If Fulton Thermal Corporation provided the heater skid, loss of head to the pump is extremely unlikely with proper fl uid level in the
combination tank.
The most common low heater in a thermal piping system is water, which needs to be boiled out at startup or anytime new piping or
fl uid is added to the thermal oil system.
Once the system has been brought up to full operating temperature, assuming that the entire system has seen fl ow, there should be
no further occurrence of low heater contamination apart from possible heat exchanger failure.
System is open Lack of back-pressure. If control valving is improper or pressure drop across the system is too low, the resulting minimal back-
pressure may not provide enough resistance for the fl ow to make the pressure switch. Check the thermal fl uid system for proper
operation of control valves.
Blocked Sensing Line on
Pressure Switch A blocked sensing line will give an inaccurate pressure reading to the pressure switch. A blocked line will need to be replaced or
cleaned. Most installations have block valves at the heater to facilitate safe isolation and cleaning of the sensing line. Do not attempt
when system is hot.
Improper Switch Setting Low Inlet Pressure Switch should be set at 10 psi less than the pressure read on the heater inlet pressure gauge at full operating
temperature of the system; or 50 psig, whichever is less.
Switch is faulty If pressure is verifi ed and reads correctly above set point on switch and the sensing line to the pressure switch is open, the pressure
switch is faulty. Replace switch, set for desired set point and test for proper operation.