Designer Guide

2
LOCHINVAR, LLC
300 MADDOX SIMPSON PKWY
LEBANON, TN 37090
www.lochinvar.com
Designer’s Guide / Knight XL Boiler
Chapter 1 – Venting
Venting is often the most difficult design element for the installation of a gas fired appliance, but
not with the Knight XL. The designs are simple and deliver ideal operation. Still, with the venting
of flue products there are important rules and regulations to follow and the installation bears a
responsibility for human safety.
Lochinvar offers nine different vent configurations on the Knight XL boiler. There are three
layouts or footprints and all are Category IV venting. They are…
Direct Vent / Sidewall
PVC/CPVC with Vent/Air Termination Plate
PVC/CPVC with Concentric Vent Kit (400-601 only)
PVC/CPVC with two pipe termination
Stainless Steel with two pipe termination
Direct Vent / Vertical
PVC/CPVC with Concentric Vent Kit (400-601 only)
PVC/CPVC with two pipe termination
Stainless Steel with two pipe termination
Rooftop Vent with Air from the Equipment Room
PVC/CPVC vent with Room Air
Stainless Steel vent with Room Air
Part 1
Four Important Ideas
Here are four important ideas we need to share
before we look at each vent configuration.
1. Vent Material
2. Air Intake Material
3. Vent & Air Intake Lengths
4. Vent & Air Intake Diameters
VENT MATERIAL
You have three vent materials to choose from. The vent for a Knight XL can be installed with
PVC, CPVC or AL29-4C Stainless Steel. Your choice.
You can choose any one of the three but we remind you to review the jobsite and check local
codes because certain situations require a specific material. For example, if you are going to
install the Knight XL in a closet you MUST use CPVC pipe or Stainless Steel pipe. You cannot
use PVC. The logical reason is, vent pipe temperatures will be higher in a tight, poorly ventilated
closet. Another example, some local codes do not allow the use of PVC or CPVC for venting flue
products. In some areas, local code demands the use of Stainless Steel vent material.
SPILLAGE OF FLUE PRODUCTS AND CARBON MONOXIDE EMISSIONS PRODUCED BY THE
COMBUSTION PROCESS CAN CAUSE SEVERE PERSONAL INJURY OR DEATH.
Warning
Venting