Chromalox specifications General, Installation, Specifications Table a, NWHMTO-3305

Chromalox®

Installation

and

RENWEAL PARTS IDENTIFICATION

SERVICE REFERENCE

DIVISION 4		SECTION NWHMTO
SALES	(Supersedes PE438)		PE438-1
REFERENCE
			161-303185-001

DATE MAY, 1999

Type NWHMTO Circulation Heater (for Regular and

1-1/16" Dia. K.O.

Fuel Oil Heating)

for 3/4" Conduit

Specifications — Table A

Internal

Thermostat

Dimensions (In.)

1" Pipe

9-

1/

4"

Model

Volts

Phase

kW

W/In2

A

B

C

Outlet (Std.)

3"

2 Mtg. Lugs Ea.

NWHMTO-3015

120

1 or 3

1

15

25-5/8

9-3/8

—

NWHMTO-3015

240 or 480

23

with Two 3/8" - 16

NWHMTO-3035

15

x1-1/2" Deep

C

B

A

240 or 480

1 or 3

3

34-3/4

22-1/2

16-1/2

Holes on 1-1/4"

NWHMTO-3305

23

Centers

1" Pipe

NWHMTO-3355

240 or 480

1 or 3

5

15

57-1/2

45-1/4

39-1/4

NWHMTO-3505

23

34-3/4

22-1/2

16-1/2

Inlet

3"

(Std.)

NWHMTO-3505

240 or 480

1 or 3

7.5

15

68-1/4

56

50

3/8" NPT

NWHMTO-3075

23

57-3/8

45-1/4

39-1/4

NWHMTO-3095

240 or 480

1 or 3

9

15

79-1/4

67

61

Pipe Plug

7"

NWHMTO-3905

23

57-1/2

45-1/4

39-1/4

GENERAL

WARNING: This heater is not intended for use in haz- ardous atmospheres where flammable vapors, gases, liquids, or other combustible atmospheres are present as defined in the National Electrical Code. Failure to comply can result in explosion or fire.

Hazardous area terminal enclosures are available, consult your local Chromalox representative for details.

The NWHMTO series is a general-purpose oil circulation heater intended for use indoors.

The 3 steel sheathed tubular elements are centered in a 2-1/2” diam- eter steel heating chamber and welded to a removable screw plug. The assembly is surrounded by 1-1/2” insulation and sheet metal jacket.

Depending upon the specifications, the NWHMTO may or may not be factory equipped with AR or other Chromalox thermostats. Such thermostats function to control outlet temperatures and limits internal temperatures under abnormal flow conditions. These controls do not fail-safe.

CAUTION: Users should install adequate back-up con- trols and safety devices with their electric heating equipment. Where the consequences of failure may be severe, back-up controls are essential. Although the safety of installation is the responsibility of the user, Chromalox will be glad to make equipment recom- mendations.

INSTALLATION

WARNING: Hazard of Shock. Disconnect all power before installing heater.

1.Vertical mounting (axis of chamber vertical as in sketch above) is preferred. (Terminal housing at top of heater)

2.When mounting heater horizontally, inlet and outlet MUST be up. In any other position, heater cannot be purged of air and elements may be seriously damaged. (See Figure B below)

3.The NWHMTO series of circulation heaters are provided with mounting lugs to support the heater chamber. Refer to sketch above for location of these mounting lugs.

4.Mount heaters to permit unrestrained expansion of chamber due to temperature. This can be accomplished by using a slotted mount-

Incorrect

Correct

ing assembly on either of the lugs.

5.DANGER: Hazard of Fire. Provide minimum of 6” spacing from a chamber and related piping to nearest combustible materi- al. Avoid operation of heater near combustible fluids or in com- bustible vapor or gas laden atmosphere.

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

7.If two or more heaters are needed to provide the needed heating capacity, arrange them for series oil flow.

8.DANGER: Possible Explosion. A pressure relief valve should be provided by customer at outlet of vessel. There should be no other valving between vessel and valve.

Correct

Incorrect

Figure A — Vertical Mounting

Figure B — Horizontal Mounting

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