Chromalox NWHO-33015 specifications Operation, Maintenance, Wiring Diagrams Table B

INSTALLATION

3.Whether vertically or horizontally, the heater should be rigidly mounted so that vibration is at a minimum since excessive vibra- tion will result in erratic thermostat operation. The NWHO-3 is provided with mounting lugs to support the heating chamber. (See photo.)

4.By using a slotted mounting assembly on either of the lugs, the heater chamber will be permitted to expand with increasing tem- perature.

5.DANGER: Hazard of Fire. Provide minimum of 6” spacing from chamber and related piping to nearest combustible material. Do not operate near combustible fluids or in combustible vapor or gas laden atmosphere.

6.Provide adequate space at terminal end to permit withdrawal of the heater from chamber should servicing be required.

WIRING

WARNING: Hazard of Shock. Any installation involving electric heaters must be effectively grounded in accordance with the National Electrical Code to elim- inate shock hazard.

1.Be sure line voltage matches heat voltage (on nameplate).

2.Electric wiring to heater must be installed in accordance with local and National Electrical Codes by a qualified person as defined in the NEC.

3.Power controllers must be used when heaters are rated 3 phase and when the heater amperage exceeds the rating of the thermostat.

4.Refer to Wiring Diagram, Table B, to properly connect the heater.

Wiring Diagrams — Table B

	240V, 1Ø	240V, 3Ø s	480V, 1Ø	480V, 3Ø s
Model	Fig.	Fig.	Fig.	Fig.
NWHO-3301	2	1	2	1
NWHO-3451	2	1	2	1
NWHO-3601	2	1	2	1
NWHO-3751	2	1	2	1
NWHO-3901	2	1	2	1
NWHO-3031	2	1	2	1
NWHO-3041	2	1	2	1

Note: Use wire size and type specified by N.E.C. 480V and 550V heaters require 600V wire, per N.E.C. Contactors and wire supplied by customer.

Contactor

Ground	L1
	L2
	L3
	120V
	or
	240V
	Thermostat
Figure 1
240V, 480V 3Øs

Ground

Figure 2

240V, 480V, 1Ø

Contactor

Line

120V

or

240V

Thermostat

Use contactor when the heater amperage exceeds the rating of the thermostat.

Note: Dotted lines indicate “customer furnished.” However, Thermostat could have been furnished by Chromalox if so specified on the order.

OPERATION

1.Do not heat solutions that are corrosive to the heating element sheath or the heating chamber.

WARNING: Type NWHO Circulation Heaters are equipped with steel heating elements and steel heat- ing chambers. It is the responsibility of the user to know the chemical composition of the corrosive solu- tion and the character of the materials entering the solution as well as the corrosive effect of the solution upon the heating elements and chamber. Chromalox cannot warrant any electric circulation heater against

failure by sheath corrosion if such failure is the result of operating conditions beyond our control.

2.Terminal ends of heater must be protected from drippings, con- densation, spray or direct spill-over of material. Their presence at the terminals may damage heater electrical insulation. Liquid-tight terminal enclosures are available to protect heater. Check with local sales representative.

3.If foreign material is carried by the liquid flow, install suitable fil- ters in the inlet pipe line to the heater.

4.Do not allow heater to operate when liquid flow is interrupted.

MAINTENANCE

1.WARNING: Hazard of Shock. Disconnect all power before servicing heater.

2.Remove heating element assembly periodically to check heater sheath for scaling, corrosion or excessive oxidation. Correct oper- ating conditions to minimize sheath deterioration.

3.Periodically check temperature control and limit control operation to insure accurate and safe process operation.

4.Check all electrical connections periodically and retighten connec- tions which may have loosened in service. Replace wire terminals that show signs of oxidation which would interfere with establish- ment of reliable electrical connections.