furnace airflow rates are provided in section 8.2 of this manual.
When a furnace is installed so that the supply ducts carry air
circulated by the furnace to areas outside the space containing
the furnace, the return air shall also be handled by duct(s)
sealed to the furnace casing and terminating outside the space
containing the furnace. This furnace may be installed, with
a two pipe sealed combustion configuration (direct vent), in a
space utilized as part of the return air supply. A filter must be
installed in the return opening of the furnace and a grill should
be installed in the space to allow proper circulation of air.
Secure ductwork with proper fasteners for type of ductwork
used. Seal supply and return duct connections to the furnace
with code approved tape or duct sealer.
Ductwork passing through an unconditioned space should
be insulated to enhance system performance.
When air
conditioning is used, a vapour barrier is recommended.
Maintain a 1 in. (25 mm) clearance from combustible materials
to supply air ductwork for a distance of 36 in.
(914 mm)
horizontally from the furnace. See NFPA 90B or local code for
further requirements.
Flexible connections can be used between ductwork and
furnace to prevent transmission of vibration.
Many states, provinces and localities are considering or
have implemented standards and/or restrictions on duct
sizing practices, ductwork leakage, and/or ductwork thermal,
airflow and electrical efficiencies. CONSULT LOCAL CODE
OFFICIALS for ductwork design and performance requirement
in your area.
4.2
DUCT EXTERNAL STATIC
PRESSURE
Higher than prescripted static pressure will decrease the air
flow, causing excessive temperature rise, opening of the
thermodisk, failure of the heat exchanger and / or poor
performance of the heat pump / air conditioning.
To measure total external static pressure, proceed as follow:
1. Run the furnace at the system maximum airflow
2. Return duct : Make sure the furnace filter is clean and
measure the static pressure between the filter and the
inlet of the furnace (negative pressure reading)
3. Supply duct : Measure the static pressure between the
furnace and the cooling coil (positive static pressure).
Tape up the hole when test is complete.
4. Substract the inlet pressure from the supply pressure.
For exemple, if you measured 0.3"w.c. in the supply and
-0.2" in the return:
0.3"w.c. - (-0.2"w.c.) = 0.5"w.c.
If the total external static pressure exceeds the maximum listed
on the furnace rating plate, check for closed dampers, register,
unproperly size duct work or incorrect dipswitch settings. Make
sure the temperature rise is coherent with the furnace rating
plate.
4.3
SMART DUCT SYSTEM
Dettson Industries also offers the Smart Duct System. Please
refer to the Smart Duct Manual (X40240) for proper installation
of this system.
Please note Smart Duct system can only be used with
approuved Smart Duct furnaces.
4.4
RETURN AIR CONNECTIONS
The return air duct must be connected to the bottom, left side
or right side. If necessary (depending on your filter restriction),
provision should be made for a double return.
In downflow configuration, side return air is not permitted, it
must be connected to bottom.
Connection to the back of the furnace is prohibited.
Static pressure in the return air duct should be -0.2"w.c. at
system maximum airflow.
4.4.1
Bottom return
Cut a rectangular opening on the bottom plate of the furnace
using the knock-outs.
In Upflow orientation when using the bottom inlet, return air
base can be used. This base allows the connection of the duct
on the side with a bottom inlet. See table 26 for the part number
corresponding to your furnace.
4.4.2
Side return
Remove 4 knock-outs on the side of the furnace of the 8 knock-
outs available. Use table 3 for suggested return size. Install the
return air inlet as per local codes.
Table 3 – Suggested Return size
Model
Return size
C30-2-V
11.25" x 24.00"
C45-2-V
11.25" x 24.00"
C60-2-V
13.25" x 24.00"
C75-2-V
13.25" x 24.00"
C105-2-V
15.25" x 24.00"
C120-2-V
15.25" x 24.00"
4.5
SUPPLY AIR DUCTS
The supply air duct must be connected to the furnace supply
outlet air duct flanges. DO NOT cut furnace casing to attach
supply air duct, humidifier, or other accessories. All accessories
must be connected to the supply or return ductwork, external
to furnace’s casing. It is recommend that the outlet duct be
provided with a removable access panel. This opening shall be
accessible when the furnace is installed and shall be sized to
allow the heat exchanger to be viewed or a probe to be inserted
for sampling the air stream. The cover attachement should
prevent leaks.
4.5.1
Ductwork acoutiscal treatment
Metal duct systems that do not have a 90 degree elbow and 10
ft. (3 M) of main duct to the first branch take-off may require
internal acoustical lining. As an alternative, fibrous ductwork
may be used if constructed and installed in accordance with
the latest edition of SMACNA construction standard on fibrous
glass ducts. Both acoustical lining and fibrous ductwork shall
14
Содержание C105-2-V
Страница 24: ...Figure 29 Direct vent clearance 23 ...
Страница 25: ...Figure 30 Other than Direct vent clearance 24 ...
Страница 32: ...Figure 31 Dimensions 31 ...
Страница 33: ...Figure 32 Two Stage ECM Wiring diagram 32 ...
Страница 36: ...Figure 33 Exploded view Cxx 2 V part 1 35 ...
Страница 37: ...Figure 34 Exploded view Cxx 2 V part 2 36 ...
