Chromalox PN400-3 specifications General, Installation, Wiring, KW/Circuit

GENERAL

The Chromalox Unitary Electric Immersion Heater, Type RST or RSTO, is a thoroughly engineered pretested package designed to give years of service vitrually maintenance free and shipped ready for installation in storage tank. They provide low watt denisty heating over a large heating surface with precise tempera- ture control for such materials as asphalt, fuel oil, pitch and tar, liq- uid sugar, lube oils, linseed oil, and many other heat sensitive compounds.

The heating elements, either metal sheath (RST) or open coil (RSTO) are housed in 3” Schedule 40 carbon steel pipes which are

welded into the tank adaptor box. Once the Unitary Immersion Heater is welded into your tank, the heating elements are remov- able without draining the tank.

The control panel contains a master circuit-breaker which is safety-interlocked so the door cannot be opened when the power is on, two contactors, a two-step indicating thermostat with the tem- perature range of 50 to 400°F*, over-temperature cutout with man- ual reset, control relay, selector switches, pilot lights, and a 120V control circuit transformer.

*Optional ranges available are 50 to 300°F or -20 to 120°F.

INSTALLATION

DANGER: Hazard of Explosion or Fire. The tank must be purged of all flammable vapors prior to cutting or welding.

1.Select a location for this installation according to the following:

A.Heating elements are removable thru the lower half of the control enclosure but adequate room must be provided for this purpose. This removal length for the RST would be equal to the length “B” dimension as tabulated in the Specifications Table 1. The element removal length for the RSTO is 3 foot since it can be bent on a 12” radius.

B.The control enclosure should not be located where it will be in direct sun light or be affected by any other heating equip- ment in the area.

2.Cut a rectangular hole in the tank approximately 1/4” larger than the adapter box dimensions tabulated on the Specification Table 1.

3.Install heater tube supports on 10 foot centers before installing Immersion Heater assembly (refer to Figure 1). Do not anchor the heater tubes to the supports as the tubes must be allowed to expand.

Note: Heater tubes should be level or slightly inclined away from the control panel.

4.Insert heater tubes and position adapter box as per Figure 1.

5.Weld adapter box to tank insuring that the weld is liquid tight.

6.Tank suction pipe should be mounted at least 2” above the level of the heaters. A separate line can be provided to drain tank after heaters have been de-energized.

Figure 1 — Typical Installation in Dished Head Tank

WIRING

CAUTION: Hazard of Electric Shock. The Unitary Immersion Heater must be grounded using ground- ing means provided in the control box and employ- ing wiring in accordance with National Electrical Code.

1.This heater assembly is completely prewired. The only wiring necessary is the terminals L1, L2, L3 on the main circuit break- er and the grounding lug in the control panel.

Note: All electrical connections should be checked and tight- ened if necessary. These sometimes loosen during transit.

2.The Unitary Immersion Heaters’s internal wiring is per the typ- ical wiring diagram (Figure 2) with the kW loads being tabu- lated in Table 2.

Table 2

		kW/Circuit
Model	A		B
RST (or) RSTO-21915	7.5		7.5
RST (or) RSTO-21920	10.0		10.0
RST (or) RSTO-21925	12.5		12.5
RST (or) RSTO-51530	18.0		12.0
RST (or) RSTO-52038	22.8		15.2
RST (or) RSTO-31518	12.0		6.0
RST (or) RSTO-41524	12.0		12.6
RST (or) RSTO-61536	18.0		18.0
RST (or) RSTO-81545	22.5		22.5
RST (or) RSTO-31720	13.3		6.7
RST (or) RSTO-41726	13.0		13.0
RST (or) RSTO-51732	19.2		12.8
RST (or) RSTO-61740	20.0		20.0
RST (or) RSTO-71848	27.4		20.6
RST (or) RSTO-31922	14.7		7.3
RST (or) RSTO-41930	15.0		15.0
RST (or) RSTO-51936	21.6		14.4
RST (or) RSTO-61945	22.5		22.5
RST (or) RSTO-72156	32.0		24.0
RST (or) RSTO-32024	16.0		8.0
RST (or) RSTO-42336	18.0		18.0
RST (or) RSTO-52548	28.8		19.2
RST (or) RSTO-62660	30.0		30.0
RST (or) RSTO-72672	41.1		31.9

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