The Reznor® Model SDH Separated Combustion Gas Heating Air Handler
Model SDH is the a separated-combustion version of the Reznor® line of pre-engineered air-handlers. Since the introduction of separated-combustion technology, Reznor products have been the industry standard. This new separated-combustion packaged heater is engineered with that same quality plus many new standard and optional features.

Model SDH is available in 11 sizes from 75 MBH to 400 MBH. Each size is designed for a minimum of 81% thermal efficiency and is available for use with either natural gas or propane. Model SDH separated-combustion heaters are approved for commercial/industrial installations in the United States and Canada by the ETL Testing Agency.

Standard features include the Reznor Tcore2® heat exchanger and single burner combustion system, a multi-try direct spark ignition with 100% lockout, pressure switch to verify venter flow, resiliently isolated venter motor, a high temperature limit control, and a centrifugal belt-driven blower capable of up to 3” w.c. of total static pressure. Both the forward curved blower and the blower motor are factory installed on vibration isolation mounts. All published airflow data are supported by AMCA tested and rated airflow performance curves. The energy usage of the system has been designed to meet the current ASHRAE Standard 90.1 (maximum 1.2 bhp per 1000 cfm).

Operation is controlled through an integrated circuit board. The circuit board monitors heater operation and has LED diagnostic indicator lights to identify abnormalities in heating control functions.

Optional features include factory-assembled, modular sections – a draw-through cooling coil cabinet module with either chilled water or DX coil and an inlet air mixing box module with a variety of configurations and damper options. A complete heating and cooling advanced digital control package is available in addition to common industry standard analog heating only and makeup air controls.

The unit also provides dehumidification of 100% outside air or a mixture of outside/return air. The self contained dedicated Re-Heat Pump™, provides 13°F – 20°F reheat temperature rise from the main evaporator coil discharge. The DX cooling coils are optimized for best performance when the reheat pump is on and off. For precise control, modulating reheat can be added.

Model SDH separated-combustion units require installation of either a horizontal or vertical vent/combustion air kit that includes a specially designed concentric adapter box. The unique box design allows for only one building penetration for both the flue outlet and combustion air inlet.

For more details on design, installation or selection of separated combustion, go to www.Rezsepc.com.

STANDARD FEATURES:
● Patented* Tcore2® Combustion System – includes titanium stabilized aluminized steel heat exchanger
● ETL certification
● Minimum 81% thermal efficiency throughout modulated range
● Proven separated-combustion technology including shipped-separate vent/combustion air kit (vertical or horizontal)
● Maximum 70°F temperature rise (optional 120°F)
● Circuit breaker protected transformer for 24-volt controls
● Integrated circuit board with diagnostic indicator lights
● Multi-try direct spark ignition with 100% lockout
● High temperature limit control
● Vibration/noise isolated venter motor, blower(s) and blower motor (spring or rubber isolators)
● L50 bearing rating with a life expectancy of 150,000 hours
● Reverse airflow limit switch
● Airflow pressure switch to verify circulating blower operation on makeup air options
● Socketed, high quality switching relays to facilitate service
● All service and vent connections from a single side
● Vent runs up to 45 feet
● Through-the-cabinet or through-the-base electrical
● Engineered heat exchanger condensate management
● Three hinged service doors with heavy duty hardware
● Fully gasketed control compartment door panel with safety door switch
● Pre-coat white gloss cabinet finish
● Slab or floor mounted; or ceiling suspended (4, 6 or 8 point base suspension based on modules selected)
● Fork lift openings built into the heavy gauge steel base

Note: * U.S. Patent No. 6,889,686

FACTORY INSTALLED OPTIONS :
● Stainless steel heat exchanger – 409 or 316 (stainless steel heat exchanger required for 70° – 120°F temperature rise)
● Heat exchanger extended warranty – 5-year or 10-year
● Natural gas or propane
● Controls
◊ Space temperature heating only
– Analog single or two-stage gas valve with room thermostat control (thermostat is available as a shipped-separate accessory or may be field-supplied)
◊ Space or discharge temperature heating/cooling (FX06/07 platform) (optional room command module required for space control)
– Digital two-stage heating/three-stage cooling
– Digital electronic modulation heating (25% low fire – natural gas; 40% low fire – propane)/ two-stage cooling
◊ Discharge temperature makeup air (heating only)
– Analog 2-stage with 2-stage ductstat or electronic sensor and 2-stage valve
◊ Discharge temperature heating/cooling makeup air
– Digital two-stage heating/three-stage cooling
– Digital electronic modulation heating (25% low fire – natural gas, 40% low fire – propane)/ three-stage cooling, reheat control
● Supply voltage – 115/1; 208/1; 230/1; 208/3; 230/3; 460/3; 575/3
● UV germicidal lamps – ultraviolet emitter for neutralization of VOCs and airborne micro-organisms for improved IAQ – not filtration. (Requires cooling coil cabinet Option AU. Separate 115/1 or 208/1 or 230/1 wiring/
breaker and a separate disconnect must be provided.)
● Inlet air filters – or 2” disposable or permanent; 2”, or 4” pleated disposable; arranged in vertical flat bank for ease of service
● Cabinet configuration and construction
◊ Left or right side controls
◊ No insulation; single or double wall with standard (R value 3.8) or high-density (R value 4.4) insulation
◊ Blower cabinet screen, inlet duct connection flange, or inlet on/off damper with duct flange
◊ Discharge duct flange or louvers (horizontal or horizontal and vertical)
● Mixing box module
◊ Five inlet configuration combinations including top, bottom, and rear
◊ Manual, motorized 2 or 3 position, motorized modulating return air, or outside air and return air dampers
◊ Direct-coupled 24VAC damper actuators
◊ Damper control selections such as 0-135 ohms resistance potentiometer, building pressure, or 0-10 volt control
● Blower motor (1/4 to 5 HP) – see pressure drops and blower charts
◊ Open dripproof, TEFC (motors meet EISA specifications for efficiency)
◊ Adjustable sheave and belt
◊ Motor contactor; IEC motor starter; or factory-installed variable frequency drive
● Cooling coil module with coil
◊ DX coil (single, 50/50, or 1/3-2/3 circuit; galvanized or stainless casing; copper or aluminum fins [coated or uncoated]) – non-ozone depleting, R410A refrigerant
◊ Chilled water coil (3-45 tons; 1/4, 1/2, 3/4, or full circuiting; galvanized or stainless casing; copper or aluminum fins [coated or uncoated])
● DX coil module with dehumidification control. Single, dual and 1/3-2/3 circuit, main DX coil with modulating or standard reheat control
● Evaporative cooling module
◊ White pre-painted or 300 series stainless steel cabinet
◊ 300 series stainless steel reservoir
◊ Recirculating pump or AquaSaver microprocessor-based, timed water distribution system
– Water recirculating pump with optional (field installed) fill and drain kit
– AquaSaver water metering device with optional (field installed) freeze protection
◊ 12” CELdek® or GLASdek® UL 900 Class II noncombustible media
◊ 1” or 2” aluminum pre-filter
◊ Water hammer arrestor (field installed)
● Unit mounted, lockable, non-fused service on/off switch
● Convenience outlet (requires separate power supply)
● Firestat
● Discharge temperature low limit
● Over/under voltage or phase loss protection
● High ambient limit (burner cutoff)
● Gas pressure switches (high, low, or both)

FIELD INSTALLED OPTIONS:
● Variable frequency drive (factory-installed is also available)
● Downturn nozzles (25-65° or 50-90°) with directional louvers
● Thermostats to match analog controls
● Gas pressure regulator
● Smoke detector (in ductwork)
● Remote control console and unit monitoring
● Main unit disconnect switch
● M-Series condenser