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FAN POWERED TERMINAL UNITS
Electric Heating Coils
Features, Selection and Capacities
Nailor Electric Coils are tested with terminal units in
accordance with UL Standard 1995 and meet all requirements
of the NEC (National Electric Code) and CSA (Canadian
Standards Association). Units are listed and labeled by the
ETL Testing Laboratory as a total package. All controls are
enclosed in a NEMA 1 electrical enclosure on the side of the
fan package for easy access.
All wiring for the motor and heater terminates in the enclosure
for single point electrical connection in the field. Each unit is
supplied with a wiring diagram. Note: NEC requires a means
to disconnect the heater power supply within sight or on the
terminal.
Standard Features:
• Automatic reset high limit thermal cut-outs.
• Magnetic contactors per stage on terminals with DDC or
analog electronic controls.
• P.E. switch per stage to carry load or pilot duty with
magnetic contactors as required with pneumatic control.
• Positive pressure airflow safety switch.
• P.E. switch for fan on parallel terminals (P35NE) with
pneumatic control.
• Fan relay for DDC fan terminals.
• Control voltage transformer (Class II) for DDC or analog
electronic terminals.
• Class A 80/20 Ni/Cr wire.
Options:
• Toggle disconnect switch.
• Door interlocking disconnect switch.
• Mercury contactors.
• Power circuit fusing.
• Dust tight control enclosure.
• Manual reset high limits.
• SCR Control.
SCR Control Option:
The SCR (Silicon Controlled Rectifier) option provides infinite
solid state heater control using a proportional signal (0 – 10
Vdc or 4 – 20 mA). This option may be specified compatible
with pneumatic, analog electronic or digital (DDC) controls.
Time proportional control of the electric heater provides
superior comfort and energy savings. The SCR controller
modulates the heater to supply the exact amount of heat
based upon the zone requirement. Room set points are
maintained more accurately, undershoot and overshoot
as associated with staged heat are eliminated, reducing
operation costs.
SCR controllers provide silent operation, as mechanical
staged contactors are eliminated. Zero cross switching of the
thyristor prevents electrical noise.
Maximum KiloWatts - 1 Stage Heat
Unit
208/240
Models
120 Volt
Size
Volt
1 phase
1 phase
30
4.5
10*
33SZE
40
4.5
10*
50
4.5
10*
1
–
8
2
–
8
3
–
8
35SE
4
–
8
35SEST
5
–
8
6
–
8
7
–
8
1
–
5.5
37SE
2
–
10.5**
37SEST
3
–
10***
4
–
8
2
–
8
3
–
8
35NE
5
–
8
6
–
8
2
–
8
37NE
3
–
8
4
–
8
*208V max is 8.5
**208V max is 9.0
***208V max is 8.5
Recommended Selection:
The table above is a quick reference guide, to illustrate
the relationship between electrical power supply, heater
capacity in kiloWatts and terminal unit size that are available
for fan powered units.
• Digital and pneumatic control terminals are available with
up to 3 stages of heat. Analog electronic
control terminals are available with 1 or
2 stages of heat only. A minimum of 0.5
kW per stage is required.
• Voltage and kilowatt ratings are sized
so as not to exceed 48 amps, in order
to avoid the NEC code requirement for
circuit fusing.
• A minimum airflow of 70 cfm (33 l/s)
per kW is required for any given terminal
in order to avoid possible nuisance
tripping of the thermal cutouts.
• Discharge air temperature should not
exceed 120°F (49°C).
480 & 600
277 Volt
208 Volt
Volt
1 phase
3 phase
3 phase
11.5
14.5
15
11.5
14.5
18
11.5
14.5
25
8
10
8
8
10
8
11.5
10
14
11.5
10
16
11.5
14.5
20.5
11.5
14.5
26
11.5
14.5
30
5.5
5.5
5.5
12
12
12
12
15.5
17
11.5
14.5
27
8
10
8
11.5
10
14
11.5
14.5
20.5
11.5
14.5
26
11.5
11.5
11.5
11.5
13.5
16
11.5
14.5
27
Tested and approved to
the following standards:
ANSI/UL
st.
1995, 1
ed.
CSA C22.2
No. 236.
C161
C
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