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3.4.3 Inlet Duct Connection to Boiler
Connect the air supply duct to the inlet air collar on the boiler. The air inlet collar is 11.875"
inlet duct to the collar with sheet metal screws at 90° angles and seal with aluminum tape or sealant.
3.4.4 Intake Duct Materials and Sizes
The air intake duct can be fabricated from
materials. The duct must be rigid enough to maintain the full required cross sectional area under all operating
conditions. Proper sealing of the intake ductwork is necessary to prevent infiltration of air from conditioned
space. Joints in
or
PVC
adhesive aluminum tape or other sealant. The installation of a birdscreen on the intake termination is
recommended. Ensure that the screen does not become blocked with snow, ice, insects, etc.
3.4.5 Category II Installations
The SONIC boilers are dual-certified for either Category II or Category IV operation. Category II appliances
operate with a non-positive vent static pressure and with a vent temperature that may cause excessive
condensate production in the vent. There are several requirements for reliable operation of the boilers under
Category II conditions:
1. A stainless steel vent adapter is required to mate the boiler exhaust connection and the vent pipe. See
the table below for the applicable part numbers.
2. A normally-closed motorized damper is required on the boiler's air intake. See the table below for the
applicable part numbers.
3. The draft, measured inside the vent at the rear of the boiler, must not exceed -0.05"
negative draft will cause nuisance trips such as flame failures.
4. The vent system must be properly drained of condensate before returning to the boiler. See
3.6.5.5 Condensate Drain
Table of Required Stainless Steel Vent Adapters and Category II Motorized Dampers
Boiler
Nom. vent
Size
Size
SC-1500
10"
SC-2000
10"
SC-3000
10"
SC-4000
10"
A normally-closed motorized combustion air damper with end limit switch is required for Category II vent
installations, and is optional for Category IV vent installations. 120VAC motorized dampers with end limit
switches are available for purchase from Harsco Industrial, Patterson-Kelley. Other damper motor voltages
are acceptable, provided they do not exceed 240VAC. The Air Damper Interlock circuit for the end limit switch
is always 120VAC which is sourced from the boiler itself. All end limit switches must be rated for a minimum
120VAC.
PVC
must be cemented. For galvanized duct, wrap each joint and seam with
CPVC
for information on installing condensate drains in the exhaust vent.
Stainless Vent
Vent adapter
Adapter
2640000133
2640000133
2640000133
2640000133
T T T T echnical Service 1.877.728.5351
,
, single wall galvanized steel, or other suitable
CPVC
Boiler Combustion
size
Air inlet
10"
12"
10"
12"
10"
12"
10"
12"
TM
P-K SONIC
Gas Fired Boiler
echnical Service 1.877.728.5351
echnical Service 1.877.728.5351
echnical Service 1.877.728.5351
W.C.
Combustion air N.C.
Motorized Damper
1004906946
1004906946
1004906946
1004906989
. Fasten the air
OD
Excessive
Section
Size
12"
12"
12"
14"
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