Thermolec Application &Technical Notes - Manual (Page 39)

SPECIFICATION FOR
OPEN COIL HEATERS
Long Form
Supply where indicated in these specifications, or where shown on drawings, CSA (NRTL/C) approved open
coil duct heaters as manufactured by THERMOLEC.
☛ 1- CONSTRUCTION:
• Frame shall be corrosion-resistant and made of galvanized steel of suitable gauge as required by CSA.
• Coils shall be made of high grade Nickel-Chrome alloy and shall be insulated by floating ceramic bushings from the
galvanized steel frame.
• Coil terminal pins shall be in stainless steel, mechanically secured and insulated from the frame by means of
non-rotating ceramic bushing.
• Coil support bushing shall be made of ceramic and shall be held in the frame by a lock which will keep it floating and
stress-free.
☛ 2- SAFETY CONTROLS:
• Heaters shall be equipped with fail-safe automatic reset disc-type thermal cut-out(s) located in the top frame
component above the heating elements.
• In addition to the automatic reset cut-out, heaters of 30KW and less, rated for voltages below 300 volts shall be
equipped with a fail-safe manual reset disc-type thermal cut-out, semi-recessed in the terminal box, facing the
heating element hairpin as required by CSA.
• The sensing element of the cut-out shall be stream mounted, shall be shielded from mechanical damage and shall
face the center portion of the heating section so as to make the heater non-sensitive to air flow direction.
• Cut-outs shall de-energize the heater in case of insufficient air flow.
• For maintenance and safety purposes, the heater shall be equipped with a built-in disconnect to switch the power
off at the heater location (option X1) and protective screens on both sides (option MS).
• Load fuses shall be supplied as recommended by NEC (National Electrical Code).
• When heaters are used in VAV systems, they should be modulating type “THERMO-V” equipped with an electronic
air flow sensor as described in item #8.
☛ 3- AIR FLOW:
• Duct heaters shall be non-sensitive to air flow direction and interchangeable for horizontal or vertical ducts without
impairing safety.
• Heaters shall be CSA approved for zero clearance in horizontal ducts.
☛ 4- MOUNTING METHOD:
• Heaters shall be open coil model SC slip-in type or model FC flanged type, as shown on the plans or on the coil
schedule.
• Slip-in heaters shall be suitable for insertion into the duct through an opening on its side and shall have a flange for
securing it to the duct side.
• Flanged heaters shall be suitable for attaching to matching flanges on the duct.
• Mounting flanges on both models shall be independent of the terminal box so as to allow installation without opening
the box or drilling into it.
☛ 5- SIZE & CAPACITY:
• Heater size, volts, phases, kilowatt and number of control stages shall be as per heater schedule.
☛ 6- INTERNAL WIRING:
• All internal wiring shall terminate on clearly identified terminal blocks.
• A wiring diagram shall be installed on the control box cover.
• Prior to shipping, heaters shall withstand tests as required by CSA.
OPEN COIL HEATER
THERMOLEC