Stelpro ASB05 User manual

INS_ASB/ASB-M-I-0212
(Replacement component list included)
Installation guide
“ ASB ” Series / “ ASB-M ” Series
Dual energy duct heater
This section must be read carefully by the installer.
www.stelpro.com
For further information or to consult this guide online, please visit our Web site.
E322241
This unit is approved according
to the Canadian and American
manufacturing standards.
ASB
ASB-M

INS_ASB/ASB-M-I-02122
Before installing and operating this product, the user and/or installer must read, understand and follow these instructions and keep them handy
for future reference. If these instructions are not followed, the warranty will be considered null and void and the manufacturer deems no further
responsibility for this product.
This product must be installed by a qualified person and connected by a certified electrician, according to the electrical and building
codes effective in your region.
The following instructions must be adhered to in order to avoid personal injuries or property damages, serious injuries and potentially fatal
electric shocks.
Make sure that all screws and electrical terminal connections are tightly secured before operating the unit in case they would have loosened
during transportation.
Protect the heating unit with the appropriate circuit breaker or fuse, in accordance with the nameplate.
Make sure the line voltage (volt) is consistent with that indicated on the unit’s nameplate.
This unit must be grounded.
Switch off the power at the circuit breaker/fuse before installing, repairing and cleaning the unit.
Make sure the unit is appropriate for the intended use (if needed, refer to the product catalog or a representative).
If the unit’s capacity is insufficient for the size of the house, it will be in operation continuously, and may become defective earlier.
Respect distances and positions indicated in the installation section.
If the installer or the user modifies the unit, they will be held responsible for any damage resulting from this modification, and the UL certification
could be void.
This unit must not come into contact with a water source and must be protected from splashes (e.g. a wet mop). Do not use it if any part has
been immersed. Moreover, do not turn it on or off when standing in water or if your hands are wet.
When cutting a piece of steel for the installation of the return duct, do not damage electrical wiring of the unit.
Because this unit is hot when in use, it may pose risks even in normal operation. Therefore, be careful and responsible when using it. To avoid
burns, do not let bare skin touch hot surfaces. Let the unit cool down for a few minutes before handling it (it stays warm for some time after
shut-down).
Never block air vents. This obstruction could lead to overheating, which could result in a fire.
Do not insert or allow foreign objects to enter any air vent as this may cause electric shocks, fires, or damages to the unit.
This unit has hot and arcing or sparking parts inside. It is not designed to be used or stored in wet areas or areas containing flammable liquids,
combustible materials or corrosive, abrasive, chemical, explosive and flammable substances such as, but not limited to, gasoline, paint, chlorine
and cleaning products.
Some areas are dustier than others. Thus, it is the user’s responsibility to evaluate if the filter must be changed based on it. Accumulated dirt
can lead to a component malfunction or discoloration (yellowing). It may cause a fire hazard if not installed and maintained in accordance with
these instructions.
Thermal protection activation indicates that the unit has been subjected to abnormal operating conditions. If the thermal protection remains
activated or activates and deactivates repeatedly, it is recommended that a qualified electrician or a certified repair centre examine the unit in
order to make sure it is not damaged. (Refer to the limited warranty).
If the unit is damaged or defective, cut off power supply at circuit breaker/fuse and call a certified repair centre. (Refer to the limited warranty).
Label all wires prior to disconnection when servicing controls. Wiring errors can cause improper and dangerous operation.
WARNING WARNING WARNING WARNING
Note:
When a part of the product specification must be changed to improve operability or other functions, priority is given to the product specification itself. In such instances, the
instruction manual may not entirely match all the functions of the actual product.
Therefore, the actual product and packaging, as well as the name and illustration, may differ from the manual.

3INS_ASB/ASB-M-I-0212
SPECIFICATIONS
“ ASB ” DUAL ENERGY DUCT HEATER
Type volts kW amps height (in) width (in) depth (in) lb kg
ASB05* 240/208 5,0/3,8 20,8/18,1 12 9/16 20 1/8 20 9/16 - 23 9/16 33,4 15,5
ASB10* 240/208 10,0/7,5 41,7/36,1 12 9/16 20 1/8 20 9/16 - 23 9/16 33,4 15,5
ASB15 240/208 15,0/11,3 62,5/54,2 12 9/16 20 1/8 20 9/16 - 23 9/16 33,4 15,5
ASB18 240/208 18,0/13,5 75,0/65,0 12 9/16 20 1/8 20 9/16 - 23 9/16 33,4 15,5
ASB20 240/208 20,0/15,0 83,3/72,2 12 9/16 20 1/8 20 9/16 - 23 9/16 33,4 15,5
ASB23 240/208 23,0/17,3 95,8/83,1 12 9/16 20 1/8 20 9/16 - 23 9/16 33,4 15,5
ASB27 240/208 27,0/20,3 112,5/97,5 12 9/16 20 1/8 20 9/16 - 23 9/16 33,4 15,5
ASB30 240/208 30,0/22,5 125,0/108,3 12 9/16 20 1/8 20 9/16 - 23 9/16 33,4 15,5
N.B. Please consult appendix 1 for more technical specifications.
*For the ASB05 and ASB10 models, no breakers are needed.
TECHNICAL DRAWING
FRONT
TOP
RIGHT SIDE
B
A
1 3/4''KOE&1 1/8''
1 3/8''KOE&1 1/8''
4 1/4''
[108mm]
20 1/8''
[512mm]
12 9/16''
[319mm]
CONTROL
4 9/16''
[116mm]
LOW VOLTAGE INLET
TYPICAL TOP & BOTTOM)
LEFT SIDE
7/8''
[22mm]
KOE Ø
7/8''
[22mm]
KOEØ
1 13/16''
[46mm]
6 7/16''
[164mm]
MODEL AB
16X18 18''16''
19X1919''19''
BREAKER
1 3/4''
[44mm]
KOE&1 1/8''
1 3/8''
[35mm]
KOE&1 1/8''
Ø
Ø
Ø
Ø
INSTALLATION
N.B. Cut off power supply at circuit breaker/fuse before proceeding to the installation.
Please note that each ASB duct heater is factory inspected before shipping in order to ensure that every component is operating efficiently.
The ASB series dual energy duct heater is available in several models of various heating capacity (from 5 to 30 kW). All these models are designed to be
installed downstream of the furnace, this is to say, on the supply side.
Installation clearances
When performing the installation, respect clearances given by the following picture 2A or 2B.
A 28” front panel clearance is required to facilitate servicing.
FURNACE
3''
[76mm] MINIMUM
7 1/2'' MINIMUM
[191mm]
VAR
10''
[254mm] MINIMUM
28''
[711mm] MINIMUM
4''
[102mm]
MINIMUM7''
[178mm]
MINIMUM
48'' [1220mm] MINIMUM
FURNACE
COOLING COIL
WALL OR OBSTRUCTION
FLUE PIPE
COOLING COIL
SUPPLY DUCT
FROM THE BLOWER
Figure 2BFigure 2A
Figure 1

INS_ASB/ASB-M-I-02124
Duct Heater Orientation
The ASB & ASB-M duct heater can be installed in a vertical or horizontal conduit (see figure 3). In the case of a horizontal installation, the control panel should
not face the floor or the ceiling (see figure 4). Such an installation could affect the safe and reliable operation of the unit.
Duct cut-out
Installer must cut an opening in the duct in order to install the duct heater unit. The following illustration gives the dimensions of that opening. If the baffles are
to be used, the installer must cut a slot on each side of the opening. These slots have to be wide enough to avoid interference with the baffles at the insertion
of the unit into the duct.
N.B : The duct cut-out must be positioned accordingly to figures 2A & 2B.
FURNACE
AIR FLOW
UP FLOW
FURNACE
AIR FLOW
DOWN FLOW
HORIZONTAL FLOW
HORIZONTAL FLOW
DUCT HEATER
DUCT HEATER
DUCT HEATER
DUCT HEATER
TEMPERATURE
SENSOR
COOLING COIL
COOLING COIL
TEMPERATURE
SENSOR
FURNACE
TEMPERATURE
SENSOR
COOLING COIL AIR FLOW
FURNACE
TEMPERATURE
SENSOR COOLING COILAIR FLOW
Figure 3 Figure 4
Figure 5
PLENUM HEATER
FURNACE
TEMPERATURE
SENSOR
COOLING COIL AIR FLOW
X
PLENUM HEATER
X
HORIZONTAL FLOW
FURNACE
TEMPERATURE
SENSOR
COOLING COIL AIR FLOW
HORIZONTAL FLOW
DUCT CUT-OUT
THERE MUST HAVE NO
INSULATION INTO THE DUCT
IN THIS AREA
4 1/2''
114mm
(FOR 16 X 18 & 19 X 19)
19 1/4''
489mm(FOR 19 X 19)
18 1/4''
464mm (FOR 16 X 18)
10''
254mm
INSERTION SLOTS MUST
BE CUT-OUT TO ALLOW
BAFFLES AND SCREWS TO
SLIDE INTO POSITION

5INS_ASB/ASB-M-I-0212
Baffle Installation
Baffles have to be installed by matching the clips on the baffles to the holes on the heat body and by securing them with self-tapping screws. Then, they have
to be cut in order to fit in the duct with a gap of 1/8” between the duct lining and the baffle edge.
N.B. : If the clips are too tight to slide, they can be opened with a flat screwdriver.
Heater Installation
Insert heat body through the opening in the duct and secure it with six self-tapping screws in the predrilled holes inside the electrical enclosure. Seal the
baffles slots and the enclosure perimeter in order to avoid air leaks.
Figure 6
Figure 7
DETAIL B
B
24''
[610mm]
19''
[483mm]
5 5/8''
[143mm]
3 1/8''
[80mm]
3 1/8''
[80mm]
19''
[483mm]
1/8" FREEPLAY BETWEN BAFFLES
AND PLENUM WALLS
1/8''
[3mm]
1/8''
[3mm]
1/8''
[3mm]
BAFFLE SECURING
SCREWS
24''
[610mm]
24''
[610mm]
23''
[584mm]
21''
[533mm]
SB 19 X 19
Model dimensions with baffles installedBaffle dimensions
SB 16 X 18

INS_ASB/ASB-M-I-02126
Positioning the duct temperature sensor
The temperature-sensor of the duct must be placed on the supply side at a good distance from the duct heater in order to avoid as much exposure as pos-
sible from the radiation of the elements.
ELECTRICAL CONNECTIONS
Electrical power supply
Note that a qualified electrician must wire this product according to the electrical and building codes effective in your region.
The duct heater must be connected to a of 240/208 VAC power supply source. Note that the nominal power values calculated are based on a supply voltage
of 240VAC.
The connection of the unit itself is made to a power block installed inside the control panel. Knockouts are punched on both sides of the unit to allow power
entry.
Please refer to the national and local electrical codes for selecting the proper cable size as well as the appropriate circuit breakers or fuses.
Before installing the unit, the installer must make sure the distribution panel is adequate to permit the connection of the duct heater .The available power must
be verified to ensure that it is sufficient to support the additional load.
The installer must make sure the heating power of the duct heater does not exceed the nominal power of the furnace burner.
MODELS “ ASB ” OPERATION
Upon a call for heat from the thermostat, the « ASB » dual energy duct heater is designed to activate either its own built-in heating assembly or an external
heating unit; The decision to activate one or the other is based upon the selected operating mode and/or outdoor temperature. To this end, the heat demand
signal is conveyed by the thermostat to the duct heater via terminals “W” and “R” while the SHQ* outdoor sensor will provide the outdoor temperature signal.
*outdoor sensor provided and installed by Hydro-Québec (province of Québec only).
A selector switch on the duct heater allows for 3 operating modes: Dual Energy Mode, Electric Mode and Fossil fuel* Mode (or gas). Simply press the selector
switch to scroll through the 3 operating modes; accordingly the selected mode will be indicated by means of either the “Fossil fuel” or “Electric” indicator light
or both (Dual Energy).
*note: the term fuel refers here to both gas and heating oil.
Dual Energy Mode
In this operating mode the duct heater will decide to activate either its own heating assembly or the furnace heat output in accordance with the outdoor
temperature sensor’s signal.
More specifically, while the thermostat calls for heat, as the outdoor temperature drops to –12oC (10.4oF) or –15oC (5oF) (depending on the climatic zone in
which you live) the outdoor sensor’s signal will trigger the duct heater to deactivate its heating assembly and trigger the furnace burner. Conversely, while the
thermostat calls for heat, as the outdoor temperature rises to –12oC (10.4oF) or –15oC (5oF) (depending on the climatic zone), the outdoor sensor’s signal will
trigger the duct heater to deactivate the furnace burner and subsequently, following a 5 minutes delay, trigger simultaneously its heating assembly and the
furnace blower.
Electric Mode
In this operating mode, regardless of the outdoor temperature sensor’s signal, the duct heater triggers its own heating assembly in response to the thermostat
signal.
Fuel Mode (or gas)
In this operating mode, irregardless of the outdoor temperature sensor’s signal, the duct heater redirects the thermostat call for heat to the furnace.
Figure 8

7INS_ASB/ASB-M-I-0212
Auto-transfer Override
In the event that a malfunction of the activated mode is detected, the duct heater will systematically override the activated mode and revert to its alternate
mode. More specifically, the ASB dual energy duct heater control board is equipped with a “duct” temperature-sensor. This device enables the controller to
detect a malfunction in the heating system (electric or fuel). When the thermostat sends a demand for heat to the duct heater controller, this will start the heat-
ing cycle of one of the two heating modes (electric or fuel) depending on the heating mode selected by the user and/or the condition of the outdoor-tempera-
ture sensor’s signal. Every time a heating cycles starts whether in electric mode or in fuel mode, a 15 minutes countdown begins.
When the countdown has finished, if the temperature of the duct does not exceed the temperature of the auto-transfer and the thermostats demand for heat
is still present, the heating mode activated at the beginning of that cycle will be deactivated and the opposite mode will be activated. For example: When the
thermostat sent the demand for heat, the controller activated the electric mode, the auto-transfer will be the fuel mode and vice versa.
At the same time the diagnostic pilot light (red) will start to blink every second indicating the auto-transfer is activated. The green pilot light will also indicate
which heating mode is taking over (for example fuel if we were heating in electric mode), as it starts to blink in alternation with the red pilot light the other heat-
ing modes green pilot light is off.
Note that if the fuel mode was selected and the burner does not function for lack of fuel for example, in this situation the heating mode will
automatically switch to the electric mode, add the five minutes delay during which the elements will not be activated due to the fact that the burner
has just finished operating.
While auto-transfer is activated, at any time the user can press the heating mode selector button to reinitialize the auto-transfer and return to the heating mode
of his choice.
Auto-transfer will remain active for a 12 hour period after which, the controller will try again to activate the faulty heating mode which initially triggered the
auto-transfer. This function is useful if the corrective measure is taken before the auto transfer is re-initialized.
Auto-transfer Temperature
The auto-transfer temperature is defined as being the minimal air temperature of the duct, which starts the auto-transfer (after a 15 minute delay). The installer
can adjust this by using the rotary button located on the control board. This is directly accessible by the cover of the electrical compartment without having
to disasemble the unit. The rotary button consists of a scale in degrees Celsius and offers an adjustable temperature range between 25°C (77°F) and 50°C
(122°F).
The automatic transfer temperature adjustement is a two-fold procedure. The installer must first take a measurement of the duct air temperature while the ASB heating
elements are full-on and the fuel furnace is not providing any heat ouput. The installer then sets the rotary dial to a temperature lesser than the duct air temperature mea-
surement. For instance, the installer could set the automatic transfer temp. adjustement to 45°C (113°F) after taking a duct air temperature measurement of 55°C (131°F).
Jumper Setting - ASB model
The programming jumpers should never be changed in any case, except for the W3 jumper, which selects the temperature display on a multi-meter in °C or °F.
If the jumpers are changed by error, their correct positions can be found using the chart below.
Jumper Position
W1 B
W2 H
W3 °C or °F according to preference
W4 R
W5 O or B (of no importance)
W10 No jumper
W14 2
ASB SERIES USER INTERFACE
Figure 9

INS_ASB/ASB-M-I-02128
Thermostat and furnace controls signals (“ ASB ” models)
The existing thermostat may be used to control the ASB dual energy duct heater. The duct heater includes a control terminal block connection located directly
on the circuit board. This makes it possible to connect the thermostat and the furnace control wires (R, W and G). Please refer to the following wiring diagrams
to connect the thermostat and the furnace to the duct heater.
Figure 11
Figure 10
TROUBLESHOOTING ASB MODEL
PROBLEM DEFECTIVE PART OR PART TO CHECK
The unit does not work - Defective thermostat, wrong thermostat setting, positioning or wiring
- Open circuit breaker or fuse
- Faulty power supply connections
- Defective transformer
The unit has power but the elements do not work - Defective relay
- Tripped manual reset thermal cut-out
The unit runs continuously - Defective thermostat, wrong thermostat setting, positioning or wiring
- Heat losses greater than the heating capacity of the unit
Element operating and/or cycling continuously - Defective 24V relay (contact probably welded)
All the element operating and/or cycling when there is a heating demand - Defective furnace fan
- Obstructed Return and/or supply air
Unit is overheating - Defective furnace fan
- Obstructed Return and/or supply air
The breaker trips when the heater is turned on - Faulty power supply connections
- Voltage higher than that indicated on the nameplate
Unable to attain desired room temperature - One or more defective elements
- Defective thermostat, wrong thermostat setting, positioning or wiring
- Voltage lower than that indicated on the nameplate
- Heat losses greater than the heating capacity of the unit
- Defective 24V relay
- Tripped manual reset thermal cut-out
The Red “Diagnostic” pilot light is always on - The duct’s temperature-sensor is defective or wrongly connected
The Red “Diagnostic” pilot light blinks every second - The Control board has detected a malfunctioning on one of the two Heating
modes and has started the auto-transfer process
The Red “Diagnostic” pilot light blinks four times every two seconds and
pause for two seconds
- The duct’s air temperature is above 68oC (154.4oF) - Dirty air filter – worn fan
belt
The green pilot light “ELECTRIC” blinks every second - The furnace burner was operating five minutes prior to a demand for heat in
electric mode or there was a power failure within the last five minutes or a prob-
lem with the duct temperature-sensor
The green pilot light “FUEL” blinks every second - There was a power failure within the last five minutes or a problem with the duct
temperature-sensor
N.B. If you do not solve the problem after checking these points, cut off the power supply at the main electrical panel and contact our
customer service (see the “Limited warranty” section to obtain the phone numbers).

9INS_ASB/ASB-M-I-0212
SPECIFICATIONS
“ASB-M” DUAL ENERGY DUCT HEATER
Type volts kW amps height (in) width (in) depth (in) lb kg
ASBM05* 240/208 5.0/3.8 20.8/18.1 12 9/16 20 1/8 20 9/16 - 23 9/16 33,4 15,5
ASBM10* 240/208 10.0/7.5 41.7/36.1 12 9/16 20 1/8 20 9/16 - 23 9/16 33,4 15,5
ASBM15 240/208 15.0/11.3 62.5/54.2 12 9/16 20 1/8 20 9/16 - 23 9/16 33,4 15,5
ASBM20 240/208 20.0/15.0 83.3/72.2 12 9/16 20 1/8 20 9/16 - 23 9/16 33,4 15,5
ASBM25 240/208 25.0 104.2 12 9/16 20 1/8 20 9/16 - 23 9/16 33,4 15,5
ASBM30 240/208 30.0/22.5 125.0/108.3 12 9/16 20 1/8 20 9/16 - 23 9/16 33,4 15,5
N.B. Please consult appendix 1 for more technical specifications.
*For the ASBM05 and ASBM10 models, no breakers are needed.
TECHNICAL DRAWING
FRONT
TOP
RIGHT SIDE
B
A
1 3/4''KOE&1 1/8''
1 3/8''KOE&1 1/8''
4 1/4''
[108mm]
20 1/8''
[512mm]
12 9/16''
[319mm]
CONTROL
4 9/16''
[116mm]
LOW VOLTAGE INLET
TYPICAL TOP & BOTTOM)
LEFT SIDE
7/8''
[22mm]
KOE7/8''
[22mm]
KOE
1 13/16''
[46mm]
6 7/16''
[164mm]
MODÈLE AB
16X1818''16''
19X19 19'' 19''
BREAKER
1 3/4''
[44mm]
KOE&1 1/8''
1 3/8''
[35mm]
KOE&1 1/8''
MODELS “ASB-M”OPERATION
The ASB-M series duct heater modulates the electric element’s output according to the set point temperature in the duct. This model was specially developed
to augment the heat from a heat pump. However, It is possible to use this unit only, without any other heat source. In any case, the ultimate goal is to obtain a
constant air temperature in the duct.
In order to achieve this, the control board reads the duct temperature and compares it to the set point chosen by the installer. The set point is adjusted via a
rotating knob accessible on the front of the unit. If the temperature read is below the set point, the electronic control activates the elements until the set point
is achieved. If the duct air temperature should pass the set point, the electronic control will deactivate the elements until the set point is achieved.
Three types of operating modes are possible: “ELECTRIC / ELECTRIC + HEAT PUMP”, “FOSSIL FUEL ONLY” and “ELECTRIC + EMERGENCY FOSSIL
FUEL”. The button on the control panel selects the heating mode. The modes, “ELECTRIC / ELECTRIC + HEAT PUMP” and “FOSSIL FUEL ONLY” are indi-
cated by a light illuminated next to the text. When both lights are illuminated, the unit is in “ELECTRIC + EMERGENCY FOSSIL FUEL” mode.
OPERATING OPTIONS
Electric / Electric + Heat Pump
When “Electric/ Electric + Heat pump mode” is selected, the duct heater only controls its own heating elements. The duct heater, while the thermostat calls
for a heat demand, modulates its heat output to attain the required (duct) temperature. Electric + heat pump: If the heating system incorporates a heat pump,
both the heat pump and duct heater are controlled by the thermostat heat demand. The duct heater modulated output complements the heat-pump output
to achieve the required (duct) temperature. (When electric/ electric + heat pump mode is selected, the “W” terminal on the duct heater terminal block labelled
“heat pump” should be free of any connection).
Fossil Fuel Only
When “Fossil Fuel Only mode” is selected, the duct heater only controls the fossil fuel furnace heat output. To enable the fossil fuel only mode the W14 (stage)
jumper must be set on 2. (See next page for wiring schematic)
Emergency Fossil Fuel
The “Emergency fossil fuel control mode” requires a one stage thermostat (W or Y signal) + emergency mode (E signal). This control mode allows the thermo-
stat to use the fossil fuel furnace as a supplemental heat source. To enable the fossil fuel only mode the W14 (stage) jumper must be set on 2. As with the elec-

INS_ASB/ASB-M-I-021210
tric/ electric + heat pump mode, the thermostat heat demands are conveyed to the duct heater (and heat pump if so equipped). However, if the duct heater/
heat pump combined heat output is still insufficient the thermostat will redirect the heat demand to the fossil fuel furnace. The emergency fossil fuel mode
requires a double stage thermostat for the fossil fuel furnace heat output is to be controlled by means of the thermostat second heating stage (see fig. 13).
Jumper Setting - ASB-M model
The programming jumpers should never be changed in any case, except for the W5 and W3 jumpers. The W3 jumper selects the temperature display on a
multi-meter in °C or °F. If the jumpers are changed by error, their correct positions can be found using the chart below.
Jumper “ELECTRIC” “FOSSIL FUEL” “AUTO EMERGENCY”
W1 M M M
W2 H H H
W3 °C or °F °C or °F °C or °F
W4 T T T
W5 O or B (according to heat pump)* O or B O or B
W10 No Jumper No Jumper No Jumper
W14 1 1 or 2 for 1 or 2 stages 1 or 2
* The W5 jumper should be set according to the heat pump’s inversion valve function. If the inversion valve is activated in heating mode, the W5 jumper
should be set in position “B”. If it is activated during air conditioning mode, the W5 jumper should be in position “O”.
Wiring diagram for duct heater model ASB-M with thermostat, furnace and heat pump
ASB-M SERIES USER INTERFACE
Figure 12
Figure 14
Rh
W
G
SHQ
R
W
THERMOSTAT
G
FURNACE
COM
NC
NO
T
T
Rh
Rc
W
Y
G
R
C
W2
Y
O
R
C
Y
G
ODuct Heater
Fan Relay
Furnace
Heat Pump
Burner
HVAC
Thermostat
Wiring diagram for ASB-M with heat pump and furnace
Figure 13

11INS_ASB/ASB-M-I-0212
TROUBLESHOOTING ASB-M MODEL
PROBLEM DEFECTIVE PART OR PART TO CHECK
The unit does not work - Defective thermostat, wrong thermostat setting, positioning or wiring
- Open circuit breaker or fuse
- Faulty power supply connections
- Defective transformer
The unit has power but the elements do not work - Defective relay
- Tripped manual reset thermal cut-out
The unit runs continuously - Defective thermostat, wrong thermostat setting, positioning or wiring
- Heat losses greater than the heating capacity of the unit
Element operating and/or cycling continuously - Defective 24V relay (contact probably welded)
All the element operating and/or cycling when there is a heating demand - Defective furnace fan
- Obstructed Return and/or supply air
Unit is overheating - Defective furnace fan
- Obstructed Return and/or supply air
The breaker trips when the heater is turned on - Faulty power supply connections
- Voltage higher than that indicated on the nameplate
Unable to attain desired room temperature - One or more defective elements
- Defective thermostat, wrong thermostat setting, positioning or wiring
- Voltage lower than that indicated on the nameplate
- Heat losses greater than the heating capacity of the unit
- Defective 24V relay
- Tripped manual reset thermal cut-out
The Red “DIAGNOSTIC” pilot light is always on - The duct’s temperature-sensor is defective or wrongly connected
The Red “DIAGNOSTIC” pilot light blinks every second (n/a when “ELEC-
TRIC” option is selected)
- The control board has detected a malfunction in the “fossil fuel” mode. Verify
the burner and level of fuel.
The Red “DIAGNOSTIC” pilot light blinks four times every two seconds
and pause for two seconds
- The duct’s air temperature is above 68°C (154.4°F)
- Dirty air filter or worn fan belt
The red “DIAGNOSTIC” pilot light blinks six times in 3 seconds and a
pause for 3 seconds
- The “Y” signal is present along with the “W” signal
- Verify the thermostat programing
The red “DIAGNOSTIC” pilot light blinks 8 times in 4 seconds and a pause
for 4 seconds
- The relay is cycling between proportional mode and stage mode for 12 hours.
The W4 jumper should be set to “T” and not to “R”
The red “DIAGNOSTIC” pilot light blinks 10 times in 5 seconds and a
pause for 5 seconds
- The W1 jumper is set to “B” instead of “M”
- There is a signal on the “W” screw thermostat control board terminal
The red “DIAGNOSTIC” pilot light blinks 12 times in 6 seconds and a
pause for 6 seconds
- The W14 jumper is set to “1” instead of “2”
- There is a signal from the second stage on the “W” screw pump control board
terminal
N.B. If you do not solve the problem after checking these points, cut off the power supply at the main electrical panel and contact our
customer service (see the “Limited warranty” section to obtain the phone numbers).
SAFETY FEATURES ( “ASB” & “ASB-M” )
The ASB and ASB-M duct heaters are designed with several safety features to guarantee safe operation. The following paragraphs describe these safety features.
Duct Overheating Detection
The ASB and ASB-M duct heater control board is able to detect if the temperature of the duct exceeds a certain critical point at which the operation could lead
to premature wear of the elements and an overheating of the unit. For instance a dirty air filter could reduce the circulation of air in the conduits to the point
where it becomes insufficient to dissipate all the heat generated by the elements or the burner of the furnace. As a result the temperature of the duct will rise
above the first threshold point fixed at 68°C (154.4°F). In this situation the control board will only indicate the event by means of a diagnostic pilot light (red). The
pilot light will blink 4 times in two seconds, followed by a two second pause. The indication of the problem can be re-initialized using the heating mode selector
button. No action other then the indication of an overheating will take place at this time.
In fuel mode, if the temperature of the duct exceeds 71°C (159.8°F) for more than two minutes (most likely the result of a very dirty filter), the control board will
switch from fuel mode to electric mode in order to lower the temperature.
In electric mode, if the temperature of the duct exceeds 71°C (159.8°F) for more than two minutes, the electric elements (max. 4) will be deactivated progres-
sively, by the minute, until the temperature of the duct is below 71°C (159.8°F). If the temperature drops below 54°C (129.2°F), the deactivated elements will be
reactivated progressively until the temperature of the duct is above 54°C (129.2°F).
Thermal Protections
The ASB dual energy duct heater is equipped with a thermo-mechanical protection, which provides the ultimate line of defence against any possible overheating.
Each element has its own automatic reset thermal protection, which protects it from overheating. Moreover, a manual reset thermal protection has been installed
in the duct heater in case the elements automatic protection should fail. The automatic thermal protection of the element opens at 71°C (159.8°F) where as the
manual thermal protection opens at 60°C (140°F).
The thermal protections provide a 93°C (199.4°F) maximum temperature limitation on the air output.
ELECTRICAL PROTECTION:
ASB/ASB-M models are equipped with one or more circuit breakers (except for ASB05 and ASB10 models).
Heating demand interlock (“ASB” only)
The demand for heat received by the control board can only operate one heating mode at a time even if the microcontroller is damaged. Indeed, an electrome-
chanical interlock built into the control board (Relay K1 see page 15), prevents the two heating modes from operating at the same time as a result from a dam-
aged microcontroller requesting erratic demands.

INS_ASB/ASB-M-I-021212
MAINTENANCE
The ASB & ASB-M dual energy duct heater itself does not require any particular maintenance. However, it is important to carry out regular maintenance on the
ventilation system as a whole. The air filter should be replaced when it is dirty and the ventilation shafts cleaned out when necessary. During the cleaning of
the conduits, the ventilator of the furnace must be inspected and cleaned if necessary. A faulty maintenance of the ventilation system will reduce the perfor-
mance of the duct heater.
N.B. : Never activate the duct heater if the ventilation system is not equipped with an air filter.
READING THE AIR TEMPERATURE OF THE DUCT WITH A MULTIMETER
The air temperature of the duct’s temperature sensor can be read with a multimeter set to voltmeter mode on the 2V scale. To do this, connect the black test
lead of the multimeter to the terminal (-) and the red test lead of the multimeter to the terminal (+) of the test connection point “VOLTMETER TEMPERATURE”
on the control board.
The value read on the multimeter must be multiplied by one hundred in order to convert it into a temperature value. The temperature unit can be read in °C or °F.
To select which temperature is displayed °C or °F, the installer simply moves the W3 jumper to the desired position.
AIRFLOW CALCULATIONS
The airflow in the ASB and ASB-M dual energy duct heater is bidirectional and the minimum air velocity is 300 FPM. It is possible to calculate the airflow of the
ventilation system using the following two formulas:
In order to calculate, the installer must initially take the air temperature reading of the duct with his multimeter (see above). The reading must be taken follow-
ing at least five minutes of heating operation. This is important to make sure that all the elements are functioning. With a thermometer, the installer must also
take an inlet temperature reading of the return air (at the return entry of the furnace) period. The inlet temperature must be 25 ± 2°C (77 ± 4 °F). With these two
temperature values, the installer is able to calculate the delta T (dT) that corresponds to the difference in temperature between the return air and the supply air
of the duct heater. Enter the nominal output power (Watts) of the unit into the formula. This value is displayed on the nameplate of the duct heater.
Figure 15

13INS_ASB/ASB-M-I-0212
This limited warranty is offered by Stelpro Design inc. (“Stelpro”) and applies to the following products made by Stelpro: models ASB & ASB-M. Please
read this limited warranty carefully. Subject to the terms of this warranty, Stelpro warrants its products and their components against defects in
workmanship and/or materials for the following period from the date of purchase: 5 years. This warranty applies only to the original purchaser; it is
non-transferable and cannot be extended.
Claim procedure
If at any time during the warranty period the unit becomes defective, you must cut off the power supply at the main electrical panel and contact 1)
your installer or distributor, 2) your service center or 3) Stelpro’s customer service department. In all cases, you must have a copy of the invoice and
provide the information written on the product nameplate. Stelpro reserves the right to examine or to ask one of its representatives to examine
the product itself or any part of it before honoring the warranty. Stelpro reserves the right to replace the entire unit, refund its purchase price or repair a
defective part. Please note that repairs made within the warranty period must be authorized in advance in writing by Stelpro and carried out by persons
authorized by Stelpro.
Before returning a product to Stelpro, you must have a Stelpro authorization number (RMA). To obtain it, call the customer service department at:
1-800-363-3414 (electricians and distributors - French), 1-800-343-1022 (electricians and distributors - English), or 1-866-766-6020 (consumers).
The authorization number must be clearly written on the parcel or it will be refused.
Conditions, exclusions and disclaimer of liability
This warranty is exclusive and in lieu of all other representations and warranties (except of title), expressed or implied, and Stelpro expressly disclaims
and excludes any implied warranty of merchantability or implied warranty of fitness for a particular purpose.
Stelpro’s liability with respect to products is limited as provided above. Stelpro shall not be subject to any other obligations or liabilities whatsoever,
whether based on contract, tort or other theories of law, with respect to goods or services furnished by it, or any undertakings, acts or omissions relating
thereto. Without limiting the generality of the foregoing, Stelpro expressly disclaims any liability for property or personal injury damages, penalties, spe-
cial or punitive damages, damages for lost profits, loss of use of equipment, cost of capital, cost of substitute products, facilities or services, shutdowns,
slowdowns, or for other types of economic loss or for claims of a dealer’s customers or any third party for such damages. Stelpro specifically disclaims
all consequential, incidental and contingent damages whatsoever.
This warranty does not cover any damages or failures resulting from: 1) a faulty installation or improper storage; 2) an abusive or abnormal use, lack of
maintenance, improper maintenance (other than that prescribed by Stelpro) or a use other than that for which the unit was designed; 3) a natural disaster
or an event out of Stelpro’s control, including, but not limited to, hurricanes, tornadoes, earthquakes, terrorist attacks, wars, overvoltage, flooding, water
damages, etc. This warranty does not cover any accidental or intentional losses or damages, nor does it cover damages caused by negligence of the
user or owner of the product. Moreover, it does not cover the cost of disconnection, transport, and installation.
The warranty is limited to the repair or the replacement of the unit or the refund of its purchase price, at the discretion of Stelpro. Any parts replaced
or repaired within the warranty period with the written authorization of Stelpro will be warranted for the remainder of the original warranty period. This
warranty will be considered null and void and Stelpro will have the right to refuse any claims if products have been altered without the written autho-
rization of Stelpro and if the nameplate numbers have been removed or modified. This warranty does not cover scratches, dents, corrosion or discolor-
ation caused by excessive heat, chemical cleaning products and abrasive agents. It does not cover any damage that occurred during the shipping.
Some states and provinces do not allow the exclusion or limitation of incidental or consequential damages and some of them do not allow limitations on
how long an implied warranty lasts, so these exclusions or limitations may not apply to you. This warranty gives you specific legal rights and you may
have other rights which vary from state to state or from province to province.
Limited warranty
E322241
This unit complies with the CSA and UL standards
Stelpro Design inc.
Saint-Bruno-de-Montarville (Quebec) J3V 6L7

INS_ASB/ASB-M-I-021214
APPENDIX 1
Control card top view
Figure 16

15INS_ASB/ASB-M-I-0212
APPENDIX 2
“ ASB ” Control panel view
Replacement components list
Figure 18
#DIAGRAM #PART DESCRIPTION
1 ELF-SB160521 SB ASSEMBLED ELEMENT, 16” LONG., 5 kW, 240 V
1 ELF-SB160421 SB ASSEMBLED ELEMENT, 16” LONG., 4 kW, 240 V
1 ELF-SB160321 SB ASSEMBLED ELEMENT, 16” LONG., 3.5 kW, 240 V
1 ELF-SB190521 SB ASSEMBLED ELEMENT, 19” LONG., 5 kW, 240 V
1 ELF-SB190421 SB ASSEMBLED ELEMENT, 19” LONG., 4 kW, 240 V
1 ELF-SB190321 SB ASSEMBLED ELEMENT, 19” LONG., 3.5 kW, 240 V
2 PROT-065 THERMAL PROTECTION, 165°F, MANUAL RESET
3 PROT-019 THERMAL PROTECTION, 140°F, AUTOMATIC RESET
4 CIR-001 SB ELECTRONIC CONTROL CARD
5 CON-010A CONNECTOR/WIRES ASSEMBLY, RELAYS OUTPUTS SB
6 TRF200040D TRANSFORMER, 208-240/24/40VA, CL.2 CL.B
7 REL-007 RELAY, T9AP5D52-2A - N.O. 20A; N.C, 10A
8 REL-006 RELAY, FR4A COIL DC 24V, N.O 30A/250VAC
9 TRI-001 HEAT SINK OF TRIAC, 40A, 600V, PANEL MOUNT, BTA40
10 BREA-001 BREAKER 120V/240V 30A 2P
10 BREA-002 BREAKER 120V/240V 40A 2P
10 BREA-003 BREAKER 120V/240V 50A 2P
A
DETAIL A
2
6
1
B
DETAIL B
4
5
3
78
9
10

INS_ASB/ASB-M-I-021216
APPENDIX 3
ASB-M with oil furnace fan circuit (R-W thermostat)
OPTO
OPTO
OPTO
OPTO
OPTO
W
R
Y
C
G
O/B
WWW
G
Rh
WWWWWWWWWWWW
G
R
G
W
C
oil furnace fan circuit
ASB-M PCB
THERMOSTAT
CR
240VAC
24 VAC
M
OPTO
LOW SPEED
HEATING SPEED
FAN LOW SPEED
SWITCH
FAN LIMIT
COM
NC
NO
FAN RELAY
YELLOW YELLOW
PURPLE
ORANGE
L1 L2/N
NO
NC
OPTO
OPTO
OPTO
OPTO
OPTO
W
R
Y
C
G
O/B
WWW
G
Rh
WWWWWWWWWWWW
G
R
G
W
C
oil furnace fan circuit
ASB-M PCB
THERMOSTAT
CR
240VAC
24 VAC
M
OPTO
LOW SPEED
HEATING SPEED
FAN LOW SPEED
SWITCH
FAN LIMIT
COM
NC
NO
FAN RELAY
YELLOW YELLOW
PURPLE
ORANGE
L1 L2/N
NO
NC
Heating elements and fan relay are activated when signals Y, O/B and G are applied to ASB-M terminal block (heat pump section).
Heating elements and fan relay are activated when signals Y, O/B and G are applied to ASB-M terminal block (heat pump section).
ASB-M with oil furnace fan circuit (R-W-G thermostat)