Energy Tech Laboratories MR212 Manuale Utente

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9
Copper Wire Ampacity 
Wire Size AWG 
Maximum Amps 
14 20 
12 25 
10 30 
8 40 
6 55 
4 70 
Electrical 
Before connecting power to the heater, read and understand this 
entire section of this document.  As-built wiring diagrams are 
furnished with each fan by the factory, and are attached to the 
door of the unit. 
 
Electrical wiring and connections should be done in accordance 
with local ordnances and the National Electric Code, 
ANSI/NFPA70.  Be sure the voltage and phase of the power 
supply and the wire amperage capacity is in accordance with the 
motor nameplate.  For additional safety information refer to AMCA publication 410-96, Recommended 
Safety Practices for Users and Installers of Industrial and Commercial Fans. 
 
1. Always 
disconnect power before working on or near a 
heater.  Lock and tag the disconnect switch or breaker to 
prevent accidental power up. 
2.  An electrical drop containing the motor power wiring is 
shipped with every fan.  The electrical drop should be 
brought through one of the conduit openings located in 
the base of the unit, run through the curb, and connected 
to a junction box inside the building.   
3.  A dedicated branch circuit should supply the motor circuit 
with short circuit protection according to the National 
Electric Code.  This dedicated branch should be run to the junction box mentioned above and 
connected as shown in a following 
illustration labeled “Fan to Building 
Wiring Connection”. 
4.  Make certain that the power source 
is compatible with the 
requirements of your equipment.  
The heater nameplate identifies 
the  proper phase and voltage of 
the motor. 
5. Units shipped with an optional 
remote panel have two electrical 
circuit drops.  It is important to run 
the motor wires in a separate conduit from the remote control wiring.  The DC wires from the unit 
temperature controller, located in the control drop, should either be shielded cable or be run in a 
separate conduit. 
6.  Before connecting heater to the building power source, verify power line wiring is de-energized.  
7.  Secure the power cables to prevent contact with sharp objects.  
8.  Do not kink power cable and never allow the cable to come in contact with oil, grease, hot 
surfaces or chemicals.  
9.  Before powering up the heater, check fan wheel for free rotation and make sure that the interior of 
the heater is free of loose debris or shipping materials. 
10.   If any of the original wire supplied with the heater must be replaced, it must be replaced with type 
TW wire or equivalent. 
Motorized Intake Damper 
On units shipped with the optional motorized intake damper, a power transformer is supplied with the unit 
if the main incoming voltage is greater than 120V.  The damper motor is automatically energized when 
the main disconnect switch is in the ON position.  No external wiring to the damper motor is required.
 
 
WARNING!!
 
Disconnect power before 
installing or servicing fan.  High 
voltage electrical input is 
needed for this equipment.  This 
work should be performed by a 
qualified electrician.