Fulton Vertical Electric (FT-N) Thermal Fluid (hot oil) Heater - Manual (Page 69)

Fulton Thermal Corp.*Electric Thermal Fluid Heaters Manual* Version 2010-0423
Page 69
2. 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.
3. If the strainer is plugged, isolate the strainer and drain that section of
piping being mindful of the temperature of the thermal fluid.
4. Remove the strainer and clean with compressed air, high-pressure
water or a cleaning solution. Replace and observe new pump suction
pressure.
e) Failed circulation pump coupling
1. A failed coupling will result in a decreased or no flow condition
through the heater. The coupling can be checked by removing the
coupling guard between the pump and pump motor.
2. The coupling should not be torn or misshapen. If the coupling needs
to be replaced, it is recommended to re-align the circulating pump
first at ambient temperature and again when it's at operating
temperature. Alignment should be within pump manufacturers'
specifications.
f) Cavitation of the circulating pump
1. Cavitation occurs when a pump experiences a loss of head or if any
low heater flashes to gas at the impeller. During this time, the pump
impeller spins without actually circulating any thermal fluid.
2. If Fulton Thermal Corporation provided the heater skid, loss of head
to the pump is extremely unlikely with proper fluid level in the
combination tank.
3. 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 fluid
is added to the thermal oil system.
4. Once the system has been brought up to full operating temperature,
assuming that the entire system has seen flow, there should be no
further occurrence of low heater contamination apart from possible
heat exchanger failure.
g) System is Open
1. 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 flow to make the pressure switch.
Check the thermal fluid system for proper operation of control valves.
h) Blocked sensing line on pressure switch
1. 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