Centrifugal Fan (Type II) Heaters

air and heat penetration capacity at floor level based on established

design temperature. Suspension from heating pipes will not be permitted.

Fans for vertical discharge type heaters shall operate at speeds not in

excess of 1,200 rpm, except that units with 53 Megajoules (50,000 Btu)

50,000 Btu output capacity or less may operate at speeds up to 1,800 rpm.

Horizontal discharge type unit heaters shall have discharge or face

velocities not in excess of the following:

Unit capacity, liters

Face velocity, meters

per second

Up to 472

4.1

473-1400

4.6

1401 and over

5.1

Unit capacity, cfm

Face velocity, fpm

Up to 1,000

800

1,001 to 3,000

900

3,001 and over

1,000

2.4.2.2

Centrifugal Fan (Type II) Heaters

Heaters shall be arranged for floor or ceiling mounting. Heating elements

and fans shall be housed in steel cabinets of sectionalized steel plates or

reinforced with angle-iron frames. Cabinets shall be constructed of not

lighter than 1.214 mm (18 gauge) 18 gauge black steel. Each unit heater

shall be provided with a means of diffusing and distributing the air. Fans

shall be mounted on a common shaft, with one fan to each air outlet. Fan

shaft shall be equipped with self-aligning ball or roller bearings and

accessible means of lubrication. Fan shaft may be either directly

connected to the driving motor or indirectly connected by adjustable V-belt

drive rated at 150 percent of motor capacity. Fans in any one unit heater

shall be the same size.

2.4.2.3

Heating Elements

Heating coils and radiating fins shall be of nonferrous alloy. Heating

elements shall be free to expand or contract and shall be pitched for

drainage. Elements shall be tested under a hydrostatic pressure of 1.4 MPa

200 psig.

2.4.2.4

Motors

Motors shall be provided with manual selection switches for

[On-Off-Automatic] [On-Off] [High/Low-Off] operation and shall be equipped

with thermal overload protection.

2.4.3

Heating and Ventilating Units

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NOTE: Indicate capacity of unit heaters and heating

and ventilating units on drawings.

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Units shall be ceiling- or floor-mounted type, self-contained, with the

heating coils, fans, dampers, and filters completely encased in a steel

housing of sectionalized steel plates or reinforced with an angle-iron

frame. Each unit shall be provided with latched, removable access panels

SECTION 15562A

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