OEM

INSTALLATION INSTRUCTIONS

HE SERIES

DUCT FURNACE MODULE

ANSI Z83.8 (2013) – CSA 2.6(2013) – Duct Furnace

HE-OEM-MAN-2

A Nameplate and Rating Plate are attached to the front shroud of the duct furnace assembly to identify the model

and serial number of this product and ratings for this furnace assembly. These plates must be left attached when the

furnace is installed in the product for identification purposes. The heater Rating Plate contains information including

gas type, maximum and minimum input rating for this furnace assembly and application, manifold pressure to provide

rated Btuh input, maximum and minimum inlet supply gas pressure, maximum and minimum airflow requirements,

output capacity and electrical ratings for this specific module.

A Rating Plate is also attached top the power burner housing by the burner manufacturer. This plate provides the listed

maximum and minimum inputs of the power burner and may not represent the acceptable maximum firing input

rate in this furnace. The burner has been orificed at the factory to provide the required maximum input for this duct

furnace at the manifold pressure marked on the Furnace Rating Plate attached to the front shroud. Never adjust

This product must be applied in accordance with the requirements of its recognition, according to Rating Tables for;

maximum input ratings, duct and cabinet clearances to heat transfer surfaces, maximum and minimum temperature

rise and maximum and minimum airflow. In addition to these specifications the Original Equipment Manufacturer of

the “Listed” equipment shall insure that the installation provides the following in accordance with its product listing:

 The duct furnace provided is installed on the positive side of the circulating air blower only.

 A pre-set High Limit Switch is provided to shut-off of the gas supply to the main burners should the outlet air

reach a temperature not in excess of 250

o

F. This limit has a fixed differential and will cycle the burner on and

off. To prevent heat build-up and possible damage to the cabinet or other components, installation of an

auxiliary manual reset limit downstream of the heat exchanger is recommended.

 Indoor Installations require a blocked vent safety switch to shut-off burner in the event of a blockage in the

vent pipe. Specify unit for indoor installation or request switch kit.

 Adequate airflow within the duct or cabinet, sufficiently well distributed to limit the maximum temperature

minimum 20 oF rise across the heat exchanger. For applications using 50% or more outside air, other

restrictions may apply. Refer to section “Airflow Consideration and Burner Turndown.

 Locate circulating blower at least 24” from closest heater surface. Locate downstream filters (if used) at least

36” from closest heater surface.

 Clearances to combustibles as appropriate for the design, but in no case less than the following unless

determined by test as part of the manufacturer’s listing:

o 6 in. – Sides and back 2 in. – Bottom 36 in. – Top 24 in. – Front

The “Listed” equipment manufacturer’s Installation and Operating Instructions should provide all necessary information

as required by ANSI Z83.8-CSA 2.6 including but not limited to the following; Installation Codes, Hazard Warnings,

operation in chemical environments, gas piping, electrical connection, Lighting Instructions, Sequence of Operation,

proper adjustment of minimum firing rate, Manual reset switches, Wiring Diagrams, Clearance to Combustibles, Airflow

and Rise ranges, Venting and troubleshooting, annual inspection and maintenance.

The final determination of the safety and suitability of this product for the specific application shall be the responsibility

of the manufacturer of the “Listed” equipment and the listing Agency.

during installation into cabinet. Do not lift module by tubes or burner housing, as damage could result.

exchanger mounting employs elongated slots for mounting bolts. Nuts and washers are used to secure heat

exchanger elements to the frame in a manner that will allow for expansion of the heat exchanger assembly

within the frame. NEVER tighten nuts to supports. Heat exchanger damage can occur.

condensate drain fittings are provided in each collector box. Drain lines should be stainless steel, as any

condensate that forms during operating cycles is corrosive, particularly to copper. Attach a drain line with

proper pitch (1/4” per 12”) to provide positive drainage of any condensate. Condensation may occur during first

few minutes, at the beginning of a heating cycle, or during air conditioning operation if furnace is downstream

Outdoor Installation

located to prevent recirculation of flue gases into combustion air supply.

necessary. Exhaust temperatures may be as high as 550 oF

Figure 2 - Standard Vertical Indoor Venting Arrangement

Gas Piping

B149) and any applicable local codes and ordinances.

bubbling indicating a leak. NEVER test for gas leaks with an open flame.

Figure 3 – Typical Burner Gas Piping

Burner Adjustment and Operation

Manufacturer’s instructions for proper set-up, adjustment and operation of the power burner installed are provided with

this furnace. The burner has been test fired at the factory after installation in the HE duct furnace, however final

adjustment is the responsibility of the unit manufacturer.

Main gas regulator must be adjusted to provide the manifold gas pressure marked on the Duct Furnace Rating Plate

to provide the proper maximum firing rate for this furnace. Note that this furnace may be listed for a lower maximum

input rating than marked on the burner rating plate.

Propane Gas: CO

F

Low fire settings will very depending on the actual minimum firing rate, however CO (ppm) should never exceed 250

ppm and flue gas temperatures should not be less than 250

o

Note that the duct furnace is a Category III appliance for non-condensing operation with a positive vent pressure.

While some condensation may occur for the first few minutes of burner operation, especially when a high percentage

of outside air is supplied, operating under continuous condensing conditions must be avoided.

input rating or less.

These conditions can result in reduced heat exchanger temperatures, especially on the secondary tubes. If the tube

surfaces fall below the dew point of the flue gases passing through them, condensation of the water vapor present in

the flue gas can occur inside the tubes. As noted above this condensate is corrosive and can damage heat exchanger.

If any of these conditions is expected, a bypass duct or section should be included so that proper airflow can be

maintained over the heat exchanger to provide sufficient temperature rise and avoid operating conditions where

continuous condensation occurs. Bypass duct should be sized to reduce airflow to provide at least a 20

o

F rise or

In applications with constant volume airflow and a high percentage of outside air, it may be necessary to limit burner

turndown (ei. minimum firing rate) in order to insure conditions that will avoid prolonged condensation in heat

exchanger. These applications are most likely to result in low temperatures on secondary heat exchanger tubes.

Bypass duct for these applications should be sized to reduce airflow over the heat exchanger to obtain the highest

temperature rise possible (up to 100

after mixing with the bypass air.

Gas Supply

 Remove the drip leg and clean any debris or liquid that may have accumulated. Re-attach drip leg and plug.

 Turn off electrical supply to unit. Verify that there is no leakage from combination gas valve (no manifold

pressure) with the system at normal inlet pressure and no power to gas valve.

Burners

 Burner should be inspected to verify that all components are free from damage and cleaned of any debris in

accordance with the burner manufacturer’s instructions provided.

Heat Exchanger / Flue Collector

Electrical Wiring

 Check wiring for loose connections or deterioration. Tighten connections and replace any wiring that is

deteriorated. Wiring materials must be replaced with wire suitable for at least 105 oC.