Harsco Industrial SC-2000 Installation & Owner's Manual page 26

3.5.5 Sealed Combustion/Direct Vent Systems
These boilers are also certified for operation with a sealed
combustion air and pressurized venting system. Such a system
employs a sealed combustion air intake duct leading from outdoors
and a sealed exhaust vent terminating outdoors. Air flow through the
system is maintained by the combustion air fan. Allowable
configurations of vent and air intake terminations are illustrated to the
right.
NOTE: Drains have been omitted for clarity.
The combined pressure drop of the air supply duct and exhaust vent
must not exceed 0.44" wc. This pressure drop includes both the
inlet and exhaust duct friction loss.
NOTE: The inlet air duct loss should not exceed 0.22" w.c.
If the air inlet and the exhaust vent terminate on the same wall of the
building they must utilize the same type of termination fitting.
Allowable termination fittings are either 90° elbows or tees.
This boiler may be installed with sidewall vent using room air. (Refer to air inlet requirements Section 3.5.2.1)
Figure 3.5.5 shows the sidewall penetration requirements. The exhaust vent must be at least 3 feet above the air
intake. The air intake and exhaust vent must extend 6" to 12" from the exterior wall and be offset.
3.5.5.1 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.
3.5.5.2 Intake Duct Materials and Sizes
The air intake duct can be fabricated from
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 must be cemented. For galvanized duct, wrap each joint and seam with adhesive aluminum tape
PVC CPVC
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.
3.5.6 Removing an Existing Boiler
When an existing boiler is removed from a common venting system, the common venting system is likely to be
too large for proper venting of the appliances remaining connected to it.
At the time of removal of an existing boiler, while the other appliances remaining connected to the common
venting system are not in operation, the following steps should be followed with each appliance remaining
connected to the common venting system placed in operation:
1. Seal any unused openings in the common venting system.
2. Visually inspect the venting system for proper size and horizontal pitch and determine that there is no blockage or
restriction, leakage, corrosion or other deficiency which could cause an unsafe condition.
3. Insofar as is practical, close all building doors and windows and all doors between the space in which the appliance
remaining connected to the common venting system are located and other spaces of the building. Turn on clothes
dryers and any appliances not connected to the common venting system. Turn on any exhaust fans, such as range
hoods and bathroom exhausts, so they will operate at maximum speed. Do not operate a summer exhaust fan. Close
fireplace dampers.
Harsco Industrial, Patterson-Kelley Technical Service 1.877.728.5351
, , single wall galvanized steel, or other suitable materials.
PVC CPVC
26
Gas Fired Boiler
Figure 3.5.5
. Fasten the air
OD
36"
Minimum
12" Minimum