LENNOX 73M72 Vent Extension Kit Instruction Manual
- June 4, 2024
- Lennox
Table of Contents
LENNOX 73M72 Vent Extension Kit
Shipping and Packing List
31W62 (LB-115012A) Used on LG/LD/KG/ZG 024-090, ZG 092-150 & SG 036, 060 Units AND 73M72 (LB-100525E) Used on SG 120 Units Package 1 of 1 contains:
- Vent transition
- Drain cap
- Bracket assemblies
- Vent straps 18- #10 – 16 X 5/8” SDST screws
- 2- 1/4-20 X 1.5 Screws 2- 1/4-20 Nuts
- 2- Split lock washers 1- Gasket
- 1-Label (73M72 only)
The following field-provided, agency-approved parts are required to complete this installation:
- 2- Lengths of 3” diameter B vent pipe (4” on 73M72) 1-3” B Vent tee (4” on 73M72)
- 1-3” Vent cap (4” on 73M72)
42W16 (LB-115012B)Used on LG/LD/KG 092-360 and SG 240 Units Package 1 of 1 contains:
- 1- Vent transition
- 1- B vent tee (4” X 4” X 3”)
- 1- Drain cap
- 2- Bracket assemblies
- 2- 1/4-20 X 1.5 Screws 2- 1/4-20 Nuts
- 2- Split lock washers 1- Gasket
WARNING
Improper installation, adjustment, alteration, service or maintenance can cause property damage, personal injury or loss of life. Installation and service must be performed by a licensed professional HVAC installer or equivalent, service agency, or the gas supplier
CAUTION
As with any mechanical equipment, contact with sharp sheet metal edges can
result in personal injury. Take care while handling this equipment and wear
gloves and protective clothing.
Application
The Vent Extension Kit is used when unit vent is too close to fresh air
intakes per building codes. The vent kit also prevents ice formation on intake
louvers.This kit is approved for installations where the vent pipe extends no
further than 3 ft. (.92m) above the top of the unit. These instructions are
intended as a general guide and do not supersede local codes in any way.
Authorities having jurisdiction should be consulted before installation.
Installation
IMPORTANT – Vent assembly must be removed to allow access to heat and blower section. Leave this instruction with the unit to ensure proper reinstallation of vent extension.
- Disconnect all power to unit.
- Remove bird screen from vent opening.
- Install vent transition in field-provided B vent tee as shown in figure 1 for SG 120 units. See figure 2 for all other units.
- Assemble the vent strap and bracket as shown in figure 3. Do not tighten screw. On LG/LD/KG/ZG/SG 024- 090 units, turn the bracket 180 degrees to allow clearance for the door handle. See figure 4.
- The opening on the vent transition is offset to avoid overlapping the combustion air intake louvers. The tee must be oriented to ensure proper positioning of the offset. Determine the bottom of the tee using figure 5.
- Slide vent strap over the bottom of tee and fit the drain cap in the bottom of the tee. See figure 6. Tighten screw in bracket flange. Secure strap and cap with screws on both sides.
- Install vent tee assembly as shown in figures 7 and 8. Make sure the gasket between the transition and the unit forms a good seal to prevent leaks.
- TRANSITION AND OPENING ARE ROUND ON LG/LD/KG/ZG 024-360 AND SG 036, 060, 240 UNITS
- Insert one of two field-provided B vent pipes into tee and secure in place with two sheet metal screws.
- Assemble vent strap and bracket as shown in figure 3 without tightening screw.
- Slide bracket assembly over the top of installed vent pipe. Secure as shown in figure 9. Make sure bracket is as high on the door as possible but beneath unit top flange.
- Install field-provided vent cap on the second vent pipe. Secure in place with two screws. Insert the vent pipe into the vent pipe which is already installed on the unit. Secure with two screws. See figure 10.
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