Lennox LS25 Series Installation Instructions Manual

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 installer (or equivalent), service
agency or the gas supplier.
CAUTION
As with any mechanical equipment, personal injury can
result from contact with sharp sheet metal edges. Be
careful when you handle this equipment.

Table Of Contents

Shipping and Packing List ..............................................2
125/200 Unit Dimensions Single Fan .............................3
250/400 Unit Dimensions Dual Fan ................................4
Unit Parts Arrangement ..................................................5
Optional Accessory .........................................................6
Requirements in USA .....................................................6
Requirements in Canada ................................................6
Additional Requirements ................................................7
Unit Heater Installation ...................................................7
Combustion and Ventilation Air.....................................10
Venting..........................................................................10
Electrical Connections ..................................................15
Gas Connection ...........................................................19
Leak Check ..................................................................20
Be sure to read and understand the
structions in this manual.
ation, service or maintenance can cause
serious injury, death or property damage.
Do not store or use gasoline or other
cinity of this or any other appliance.
formed by a qualified installer, service
agency or the gas supplier.
RETAIN THESE INSTRUCTIONS FOR FUTURE REFERENCE
WARNING
FIRE OR EXPLOSION HAZARD.
Failure to
ly could result in serious injury, death,
or property damage.
WHAT TO DO IF YOU SMELL GAS:
Do not try to light any appliance.
Do not touch any electrical switch; do not use
any phone in your building.
Leave the building immediately.
Immediately call your gas supplier from a
neighbor's
structions.
If you cannot reach your gas supplier, call the
fire department.
INSTALLATION
INSTRUCTIONS
LS25
125,000 to 400,000 Btuh Series
SEPARATED COMBUSTION UNIT HEATERS
508064-01
1/2021
Replaces 10/2020
Note - Unit heaters are designed for indoor use only.
Unit Start-Up ................................................................20
To Turn Off Gas to Unit ................................................21
Heating Sequence of Operations ................................21
Ignition Control LED ....................................................22
High Altitude Adjustments ............................................22
Gas Flow .....................................................................22
Gas Pressure Adjustments ..........................................22
Limit Control Switch ......................................................23
Louver Vane Adjustment ..............................................23
Combustion Air Pressure Switch .................................23
Flame Roll-out Switch ..................................................23
Service..........................................................................23
Start-Up and Performance Checklist ...........................24
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