heatco EM Series User guide

EM Series Application
High Efficiency Condensing Duct Furnace
ANSI Z83.8 (2016) - CSA 2.6M (2016) –Gas-Fired Duct Furnace
161202

EM Series Indirect-fired Duct Furnaces
Efficiencies up to 96%
EMA Series - Inputs from 180,000 to 720,000 Btuh
EMG Series –Inputs from 90,000 to 360,000 Btuh
EM Series units employ a stainless steel primary heat exchanger
similar to conventional 80% efficient furnaces, but also incorporate
a (recuperative) heat exchanger to extract additional heat from the
flue gases.
Additional heat is transferred to the circulating air stream and flue
gas temperatures are reduced below their dew point temperature.
Water vapor present as a by-product of the combustion process, is
condensed in the recuperative heat exchanger.
This process releases another 972 Btu/lb. of water condensed
(latent heat of vaporization).

A fully condensing heater can produce up to 1 gallon of water per
hour for every 100,000 Btuh of input.
The recuperative heat exchanger tubes are made from super
ferritic stainless steel alloy, resistant to the corrosive condensate
formed in this heat exchanger.
Aluminum fins attached to the exterior tube surfaces enhance heat
transfer from the recuperative heat exchanger to the circulating air
stream.

CONDITIONS OF APPLICATION
Basic application guidelines are similar to mid efficiency furnace
applications including:
Must be installed on the positive pressure side of the circulating air
blower
Must be installed in a non-combustible duct or cabinet
The Heat exchanger must be properly sheeted to direct all airflow over
tubes and eliminate by-pass air for optimum performance.
No portion of the heat exchanger exposed outside the duct or cabinet
The duct furnace must have an ample supply of combustion air to the
vestibule / burner compartment.
The Duct furnace must be connected to a properly designed venting
system to convey flue gases outside of the heating unit and the heated space
to the outdoors and away from combustion air inlet.
Must be applied applied in accordance with manufacturer’s listed input ratings,
maximum and minimum airflows.

EM Series
Patent Pending heat exchanger design with the recuperative coil located
between primary heat exchanger passes.
Circulating air may enter either side of the furnace, reducing the number
of configurations.
Recuperative heat exchanger is
located between passes of
primary heat exchanger
depending on airflow condition.

Configurations
Maximum 5:1 Turndown
10:1 Turndown
10:1 turndown designs require two induced draft fans per furnace
EM furnaces may be installed in series provided the entering air temperature to
the downstream furnace does exceed 80oF.

EM Series - Application Summary Table
Parallel heater installations are acceptable for EM Series with all
configurations.
EAT
LAT
Location
Configurations
Eff. %
< 80 oF
< 160 oF
Outdoor, Indoor
All
≥93%
Duct
Furnace
Duct
Furnace
Airflow
Top View
OK

Venting
Safe operation of indirect-fired gas furnaces requires a properly operating
vent system which vents all the products of combustion (flue gases) to
the outside atmosphere.
EM Series duct furnaces are listed for Category II or IV vents. Category II furnaces
operate with a negative vent pressure and Category IV furnaces operate with a positive
vent pressure. Vent gas temperatures are typically less than 150 oF.
The vent piping must be exclusive to a single furnace and induced draft fan.
Common vent headers may not be used.
The venting system must be gas tight and water tight.
Use Schedule 40 PVC pipe or vent pipe listed to UL 1738. In Canada, the vent pipe
must be approved to ULC S636.
When using PVC pipe for venting, sections must be solvent welded (glued)
consistent with industry standards and applicable local codes. Primer and cement
for joints must conform to applicable ASTM standards.
Proper installation of the vent system must also assure drainage of condensate to
prevent deterioration of the vent system.
Do not use dampers in vent pipes.
All pipe openings external to building must have a protective screen installed.

Outdoor Installations
The venting system is designed for direct discharge of flue gases to the
outdoors.
Vent pipe diameter depends on furnace input rating. See Table below for
required pipe diameter for vent installation.
All vent piping is installer provided.
A coupling is installed on the induced draft fan for attachment of vent pipe.
Depending on orientation a drain hose may be attached to the ID fan.
Flue Products must be directed downward.
Table –Outdoor Vent Pipe Sizing
For vent piping attached to a single induced draft fan
Input Rating (Btuh) Input Rating (W) Vent Pipe Dia.
90,000 –135,000 26,376 –39,564 3 in. (76 mm)
180,000 –360,000 52,753 –87,921 4 in. (102 mm)

Figures –Outdoor Venting
Side Discharge
Vent
Pipe
Install
Termination
Screen
12.0" (0.3m) Min.
18.0" (0.45m)Max.
18" (.45m) Minimum above
grade or expected snow level
45oor 90o
Elbow
For horizontal runs, the vent pipe should be pitched downward ¼” per foot
toward the inducer fan drain.

Top Discharge
Flue gases must be directed downwards

Indoor Installations
Installations with Ambient Combustion Air Supply
For indoor installations, duct furnaces typically draw combustion air from
the space surrounding the heating unit. Customer designed cabinets
must have properly sized Combustion air openings must be provided in
a panel with access to the burner vestibule area.
Installation must be in an unconfined space with sufficient volume for all
appliances located in the space. A single, properly sized pipe from the
duct furnace vent connector to the outdoors must be provided.
Furnaces may be vented vertically or horizontally as shown in Figures
below.

Vertical One-Pipe Vent
Side Discharge Top Discharge
To Building Exterior
Connect condensate
drainper Section VII
Standard Vent
Drip Leg (US only)
For top discharge orientations, a flue exhaust drain coupling is provided and
must be installed for proper condensate drainage from venting system.

To Building
Exterior
Pitch Vent pipe
up ¼” per foot
Connect to
condensate drain
Horizontal One-Pipe Vent
Figure a)
Figure b)

Vent pipe diameter and maximum vent length are determined by furnace input
rating as shown in Table.
Model
Size
Input (Btuh)
Flue Exhaust (Vent Pipe)
Max. Vent
Pipe
Length
Diameter
Material
090
90,000
3"
PVC
70’
135
135,000
3"
PVC
70'
180
180,000
4"
PVC
70'
225
225,000
4"
PVC
70'
270
270,000
4"
PVC
70'
315
315,000
4”
PVC
50'
360
360,000
4”
PVC
50'
400
400,000
(2) 4”
PVC
(2) 70'
450
450,000
(2) 4”
PVC
(2) 70'
540
540,000
(2) 4”
PVC
(2) 70'
630
630,000
(2) 4”
PVC
(2) 50'
720
720,000
(2) 4”
PVC
(2) 50'

Outdoor Combustion Air Supply –Separated Combustion
Provide outside combustion air in applications with poor indoor air quality or
when furnace is located in de-pressurized area.
Combustion air is supplied from outdoors into the furnace burner compartment
through a properly sized pipe attached to the air intake collar.
This duct furnace installation requires a two (2) pipe separated combustion vent
system with separate air intake and vent pipes terminating in the same
pressure zone.
The venting and combustion air supply must be exclusive to a single
furnace.
Do not use dampers in vent or combustion air pipes.

Separated Combustion - Indoor Vertical Venting
Side Discharge Top Discharge
Combustion
Air Inlet
18.0" (0.3m) Min.
To Building Exterior
Connect condensate
drains
Standard Vent
Drip Leg (US only)
Vent Pipe

Separated Combustion - Indoor Horizontal Venting
To Building
Exterior
Pitch Vent pipe
up ¼” per foot
Combustion
Air Inlet
Connect condensate
drains
Both the furnace and vent system must be connected to a condensate removal
system.
The maximum vent length is the equivalent length of pipe, including any elbows
and fittings. (Note: for 90o wide sweep elbows, equivalent length is 5 ft.)
Combustion air pipe should be approximately the same length as the vent pipe
so that air intake and vent discharge are in same pressure zone
Note: When single wall galvanized pipe is used for air pipe, joints must be
sealed with silicone sealant or metallic tape.

Vent pipe and air inlet pipe size depends on input rating of the furnace. See
Table following for sizing and materials based on model size and input rating.
Minimum length is 5 ft.
Vent and Combustion Air Pipe Sizing for Separated Combustion
Model
Size
Input (Btuh)
Combustion Air Inlet
Flue Exhaust (Vent Pipe)
Max. Vent
Pipe
Length
Diameter
Material
Diameter
Material
090
90,000
3"
PVC
3"
PVC
35’
135
135,000
3"
PVC
3"
PVC
35'
180
180,000
4"
PVC
4"
PVC
35'
225
225,000
4"
PVC
4"
PVC
35'
270
270,000
6"
Galv. Steel (or) SS
4"
PVC
35'
315
315,000
6”
Galv. Steel (or) SS
4”
PVC
25'
360
360,000
6”
Galv. Steel (or) SS
4”
PVC
25'
400
400,000
6”
Galv. Steel (or) SS
(2) 4”
PVC
(2) 35'
450
450,000
8”
Galv. Steel (or) SS
(2) 4”
PVC
(2) 35'
540
540,000
8”
Galv. Steel (or) SS
(2) 4”
PVC
(2) 35'
630
630,000
10”
Galv. Steel (or) SS
(2) 4”
PVC
(2) 25'
720
720,000
10”
Galv. Steel (or) SS
(2) 4”
PVC
(2) 25'

Vertical Vent Termination
24" (0.6m) Minimum
From adjacent wall
or building
6" (152mm)
Minimum
Combustion Air
Inlet Pipe
Vent Pipe
Roof flashing at
all penetrations
90o Elbow
Vent Pipe
45o or 90o
Elbow
Install
Termination
Screen
12" (0.3m) Minimum
Above roof or snow line
12" (0.3m) to 18" (0.45m)
Above combustion
air intake)
Combustion Air
Inlet Pipe
Install
Screen