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

Page 73

Fulton Thermal Corp.*Electric Thermal Fluid Heaters Manual* Version 2010-0423

Page 73

2. Observe heater outlet pressure at temperature with all users / heat

exchangers calling for heat (100% user). Observe heater outlet pressure

at temperature with all users / heat exchangers not calling for heat

(100% bypass).

3. Bypass regulating valve(s) should be adjusted to equal flow condition

through users. Call or e-mail Fulton for further details.

4. It may be possible that an automatic control valve has failed. If this is the

case, the valve should be replaced.

b) Improper switch setting

1. The High Inlet Pressure Switch should be set at ambient temperature.

The setting should be 5 psi over than the maximum pressure read on the

heater outlet pressure gauge during proper operation.

c) Differential Pressure Switch

1. Units newer than mid-1993 have a Differential Pressure Switch. This is a

normally open diaphragm switch that closes with a proper heater

differential pressure between the heater inlet and outlet.

2. The purpose of the Differential Pressure Switch is to protect the heater

coil from too high of a temperature and to protect the thermal fluid from

exceeding its maximum film temperature. Each heater model number

has a specific minimum differential pressure.

3. See Section 1 if you do not know this pressure. This pressure is the

difference in pressure between the heater inlet pressure gauge and the

heater outlet pressure gauge.

Differential Pressure Switch Break

a) An obstruction downstream of the heater outlet

1. Any obstruction downstream of the flow switch(es) will increase the

pressure that the heater outlet sees. Any increase in outlet pressure will

result in diminished flow. This obstruction will generally result from an

improper valve setting.