SECTION 15835 ELECTRIC HEATING UNITS

This spec was part of the Des Plaines, IL River WRF project that bid Feb 26, 2015.

SECTION 15835 ELECTRIC HEATING UNITS
PART 1 - GENERAL

1.1 SECTION INCLUDES

A. Electric Unit Heaters - Standard.

B. Electric Unit Heaters – Explosion Proof & Corrosion Resistant

C. Electric Baseboard Heaters

D. Electric Wall Heaters

1.2 REGULATORY REQUIREMENTS

A. Conform to applicable code for internal wiring of factory wired equipment.

1.3 DELIVERY, STORAGE, AND HANDLING

A. Protect units from physical damage by storing in protected areas and leaving factory covers in place.

1.4 SEQUENCING AND SCHEDULING

A. Install units (equipment exposed to finished areas) after walls and ceiling are finished and painted. Avoid damage.


PART 2 - PRODUCTS

2.1 ELECTRIC UNIT HEATERS - STANDARD

A. Assembly:  UL listed and labeled assembly with terminal box and cover, and built-in controls.

B. Heating Elements: Enclosed copper tube, aluminum finned element of coiled nickel- chrome resistance wire centered in tubes and embedded in refractory material or exposed helical coil of nickel-chrome resistance wire with refractory ceramic support bushings, as applicable.

C. Cabinet:  18 gage steel with easily removed front panel with integral air outlet and inlet grilles.

D. Element Hangers: Quiet operating, ball bearing cradle type providing unrestricted longitudinal movement, on enclosure brackets.

E. Fan: Direct drive propeller type, statically and dynamically balanced, with fan guard.

F. Motor: Horizontal models with permanently lubricated sleeve bearings; vertical models with grease lubricated ball bearings.

G. Mounting Bracket: Provide with Universal wall or ceiling bracket.

H. Control: Provide integral power disconnect switch and integral thermostat.

I. Provide electric unit heaters with capacities as scheduled or indicated on drawings. Acceptable manufacturers to be: Qmark type MUH unit heaters, Markel, or TPI.

2.2 ELECTRIC UNIT HEATERS - CORROSION RESISTANT AND EXPLOSION PROOF

A. Electric explosion proof unit heaters shall be INDEECO ULTRA-SAFE Series T3C, of the KW rating, voltage and phase specified in the schedule. They shall be forced fan type. Factory Mutual and CSA Approved for:

1. Class I, Divisions 1 and 2, Groups C and D; Class II, Divisions 1 and 2, Groups F and G Ignition Temperature Code No. T3C, 320°F (160°C) (standard construction).

2. Note: No substitutions allowed for this type of unit.

B. Unit heaters shall have dual automatic reset thermal cutouts for redundant over temperature protection, controlling magnetic contactor and 24 Volt control circuit transformer housed in a NEMA 7, 9 case aluminum enclosure.

C. The heat exchanger shall be liquid-to-air design, utilizing a copper tube core with integral aluminum fins. Nontoxic, inhibited, propylene glycol heat transfer fluid shall be used that provides freeze protection down to -49°F (-45°). Pressure relief valve setting to be 70 psig. The heat exchanger shall include industrial grade INDEECO electric heating elements.

D. Heat exchanger and aluminum fan blade to be enclosed in an industrial grade, corrosion resistant cabinet fabricated from epoxy-coated, 14 gauge steel. Adjustable outlet louvers to have minimum opening safety stops.

E. Fan motor shall include permanently lubricated ball bearings and built-in thermal overload protection. Motor to operate at line voltage and be prewired to the control enclosure to eliminate the need for separate field wiring to the motor.

F. The heater shall be provided with an INDEECO accessory mounting kit as applicable designed to bear the weight of the heater assembly.

G. Code C1 – 316 Stainless Steel Corrosion Resistant Construction: 316 Stainless steel heat exchanger with aluminum fins, 316 stainless steel cabinet: aluminum fan blade: cast aluminum NEMA 4X, 7,9 control enclosure: corrosion-resistant hardware: corrosion- resistant protective coated motor which has passed the ASTM B117 salt-spray test.

H. The following factory installed and prewired control options are to be supplied:

1. Adjustable built-in thermostat.

2. Disconnect switch with external handle.

3. Two position auto/fan selector switch for fan only control.

4. Pilot light

5. "Heater On" to indicate when heating elements are energized.

6. "Warning" indicates when thermal cutouts have tripped which indicates heater needs to be serviced.

2.3 ELECTRIC BASEBOARD HEATERS

A. Enclosures shall be constructed of reinforced 16 gauge steel to withstand heavy-duty, commercial-institutional use. A built-in wireway runs length of heater.

B. Heating elements shall be steel tubular with aluminum fins.

C. Each electric baseboard shall be completely factory assembled, wired, tested, and shipped as a single assembly to eliminate jobsite confusion and loss of parts, and to speed installation.

D. All electric baseboards and electrical accessories shall be listed by Underwriters Laboratories, Inc.

E. Manual disconnect switch shall provide tamper-resistant means of disconnecting individual convector power circuit for service or temporary shutdown.

F. Comfort control SPST thermostat with adjustment range between 55?F to 85?F and manually set "No Heat" position shall be factory installed in baseboard cabinet. "No Heat" position shall deenergize heating elements.

G. Enclosure shall be chemically treated to resist corrosion and finished in neutral white baked enamel. Finish shall be mar and temperature resistant to retain appearance throughout years of usage.

2.4 ELECTRIC WALL HEATERS

A. Heavy-duty 16 gauge steel bar grille construction with tamper resistant construction and surface mounting box.

B. Steel finned metal sheath electric heating elements.

C. Integral thermostat - tamper resistant.

D. Thermal overheat protectors, built in power disconnect switch, built in fan delay switch.

E. Permanently lubricated totally enclosed fan motor. U.L. listed.

F. Provide electric wall heaters with capacities as scheduled or indicated on drawings. Acceptable manufacturers to be: QMark type AWH 4000 Series or CWH1000 Series as indicated on the equipment schedule, or Pre-Approved equal.


PART 3 - EXECUTION

3.1 COORDINATION

A. For electric wall heaters; coordinate recessed openings in walls to accept recessed heater cabinet. Coordinate with General Contractor.

3.2 EXAMINATION

A. Verify that surfaces are ready to receive work and opening dimensions are as instructed by the manufacturer.

B. Verify that required utilities are available, in proper location, and ready for use.

C. Beginning of installation means installer accepts existing surfaces.

3.3 INSTALLATION

A. Install in accordance with manufacturer's instructions.

B. Install heaters as indicated.

C. Hang unit heaters from building structure utilizing mounting brackets. Furnish with heaters. Mount as high as possible to maintain greatest headroom unless otherwise indicated on plans.

D. Install electric heating equipment including devices furnished by manufacturer but not factory-mounted. Furnish copy of manufacturer's wiring diagram submittal. Verify that electrical wiring installation is in accordance with manufacturer's submittals and installation requirements of Division 16 sections.

3.4 CLEANING

A. After construction is completed, including painting, clean exposed surfaces of units. Vacuum clean coils and inside of cabinets.

B. Touch-up marred or scratched surfaces of factory-finished cabinets, using finish materials furnished by manufacturer.



END OF SECTION