Thermolec FC, SC, ST, FT Installation, Operating And Maintenance Instructions

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Electric Heating and Controls

Installation, Operating and Maintenance Instructions for

THERMOLEC electric heaters - type FC & SC - (or tubular FT & ST).

1- Mechanical Installation of THERMOLEC heaters.

1.1 Handling. 1. Remove the shipping covers just before installation.

2. Inspect the heater carefully and report any damage to the manufacturer.
DO NOT INSTALL A DAMAGED HEATER.

1.2 Installation.
Heater Position

1.2.1 The axis of the duct must always be perpendicular to the face of the heater.

1.2.2

The heating elements must always be installed horizontally.

1.2.3

1.2.4 Cut an opening in the side of the duct.

1.2.5

1.2.6

1.2.7 If the heater is heavy, use additional hangers to support the heater.

The air direction may be either vertical or horizontal, but when the unit is installed horizontally, the cut-out cover
must be on top.

Model SC or ST (Slip-in type) (Please see drawings page 4).

Slip the heater into the duct until the hole is completely covered by flanges around the heater.
Fasten the heater to the duct with sheet metal screws and seal openings with a suitable sealing compound.

Model FC or FT (Flanged type)

1.2.8 Flange both ends of the duct outwards on three sides to match the heater’s flanges.

1.2.9 Fasten the heater to the duct with sheet metal screws. (For heavy heaters, use nuts and bolts and additional

hangers to support the heater).

1.2.10

Seal openings with a suitable sealing compound.

1.2.11 Spacing Requirements to obtain Optimal Operating Conditions (Please see drawings page 4).

•

** inches between the heater and elbows in the duct.
** inches between the heater and branches in the duct.
** inches between the heater and sharp transitions of the duct.
** = minimum distance = the largest of two dimensions (

Examples: heater of 12” x 12” minimum distance 12”.
heater of 30” x 12” minimum distance 30”.
Heater of 60” x 30” minimum distance 48”.

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•

heater.

•

•

service.

•

the control box cover and obstructions to allow slipping the heater out the duct and to allow safe servicing.

24 inches between the heater and filter frames.

48 inches between the heater and a double outlet fan, except with split duct design.
30 inches between the heater and access doors or diffusers, except if a metal screen is supplied with the

1 inch between the duct at the outlet side and combustible materials for a length of 72”, for vertical ducts only.

For the flanged type, 24 inches between the control box cover and obstructions to allow space for installation and

For the slip-in type, width of the duct (dimension W) + depth of the control box + ten (10) inches between

(Please see drawings page 4).

W or

H) up to 48”.

October 2008

1.2.12 Important Notes

• Do not install a duct heater in a vertical duct directly above a ceiling diffuser or an opening in the ceiling.

• Do not install standard heaters outdoors. Order a heater with weatherproof control box instead.

• Do not install spray humidifiers upstream of duct. Install it downstream instead.

• Do not cover the control box with thermal insulating materials.

• Use special air intake louvers of weatherproof construction for preheat duct heaters to avoid intake of water or snow
particles. Make sure that motorized damper blades are not blocked with snow or dirt. Inspect the dampers regularly to
ensure a suitable airflow.

2- Electrical Installation of THERMOLEC heaters.

2.1 Disconnect all power sources before opening the control box and working within.

2.2 Read the nameplate carefully and consult wiring diagram before starting to wire.

2.3 Supply wires:

Use only wires suitable for 75°C. Wires shall be sized according to the Canadian Electrical Code requirements.
All wires must be brought in through knock-outs.

2.4 Disconnecting means:

Install a disconnect switch close to the heater according to the code unless a disconnect switch is already built into
the heater.

2.5 Control circuit wiring: Use class 2 wiring for control circuit connections to the duct heater.

2.6 Magnetic contactors:

If magnetic contactors are mounted outside of the duct heater, use only contactors approved for:

• 250,000 operations when controlled by auto-reset thermal cut-out (A) and by other switching devices in series with
this cut-out (thermostat, step controller, air flow switch, etc.).

• 100,000 operations when controlled by auto-reset thermal cut-out (A) alone.

• 100,000 operations when controlled by auto-reset thermal cut-out (A) plus manual reset cut-out in series.(A&M).

• 6,000 operations when controlled by manual reset cut-out (M) alone.

2.7 External Controls ratings:

Rating of external control devices shall be suitable for handling the VA ratings as marked on the nameplate,
otherwise, a back-up relay must be used.

2.8 Air Flow Interlock:

Heaters are generally supplied with one extra terminal marked (
Remove jumper between terminals

C before connecting the fan interlock, Select a suitable air flow sensing

I and

I) for fan interlock or air sensing device connection.

device of the differential pressure sensing type, with snap acting contacts. A slow make, slow brake device may
cause undue cycling and in some instances chattering of the contactors. When fresh air dampers are used, make
sure the heater is properly interlocked to prevent it from being energized before the damper is fully open.

3- Operating THERMOLEC Heaters.

3.1 Minimum air flow.

Ensure that sufficient air flow as marked on the nameplate is passing through the heater. Air flow should be evenly
distributed across the entire face of the heater. Use air turning vane at duct elbows and splitter damper at duct
branch-offs to streamline the air flow in the heater. Use suitable air flow sensing device or interlock the heater with
fan. An insufficient air flow will lead to the opening of the auto-reset thermal cut-out or damage to the heating
elements.

3.2 Warning.

The air flowing through the duct where the heater is installed shall not contain any combustible particles, nor any
flammable vapor or gas.

3.3 Air Temperature.

The air temperature should not exceed 27°C (81°F) at the heater inlet and 66°C (151°F) at the outlet.