P-K MACH
®
Gas Fired Boiler
Technical Service 1.877.728.5351
Revised: January 3, 2020
Released: January 3, 2020
Patterson-Kelley 2020
All Rights Reserved.
1004905981 P-K MACH C1500H-C4000 Installation and
Owners Manual (Rev F Jan-2020).docx
Page 34
3.5.4 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 below.
NOTE
Drains have been omitted for clarity. 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
by at least 48” as shown. The inlet
air duct loss should not exceed 0.22” W.C
.
The combined pressure drop of the air supply duct and
exhaust vent must not exceed 0.44” W.C. This
pressure drop includes both the inlet and exhaust duct friction loss. This boiler may be installed with
sidewall vent using room air. Allowable termination fittings are either 90° elbows or tees. This boiler may
be installed without termination fittings if both the exhaust and air intake are on the same wall of the
building, see Section
3.5.5 Inlet Duct Connection to Boiler
Connect the air supply duct to the inlet air collar on the boiler. Fasten the air
inlet duct to the collar with
sheet metal screws at 90° angles and seal with aluminum tape or sealant.
3.5.6 Intake Duct Materials and Sizes
The air intake duct can be fabricated from PVC, CPVC, single wall galvanized steel, or other suitable
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 PVC or CPVC must be
cemented. For galvanized duct, wrap each
joint and seam with adhesive aluminum tape or other sealant. The installation of a
1” x 1” birdscreen
on the intake termination is recommended. Ensure that the screen does not become blocked with
snow, ice, insects, etc.
12” Minimum
36”
Minimum
Air Inlet
Exhaust
Vent
