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INSTALLATION
INSTRUCTIONS
UNIT HEATERS
507930-04
5/2021
Supersedes 507930-03
Shipping and Packing List ..............................................2
LF25-030/105 Compact Unit Dimensions.......................3
Compact Unit Parts Arrangement ...................................4
LF25-125/200 Standard Unit Dimensions ......................5
LF25-250/400 Standard Unit Dimensions ......................6
Standard Unit Parts Arrangement...................................7
Optional Accessory .........................................................8
Requirements in USA .....................................................8
Requirements in Canada ................................................8
Additional Requirements ................................................9
Unit Heater Installation ...................................................9
Rotation of Combustion Air Inducer - 125/150.............. 11
Combustion and Ventilation Air.....................................12
Venting..........................................................................12
Electrical Connections ..................................................17
Gas Connection ...........................................................22
Leak Check ..................................................................23
Unit Start-Up ................................................................23
To Turn Off Gas to Unit
................................................24
Heating Sequence of Operations ................................24
Ignition Control LED ....................................................25
High Altitude Adjustments ............................................25
Gas Flow .....................................................................25
Supply Gas Pressure Adjustments ..............................25
Supply Pressure Measurement ....................................25
Manifold Pressure Measurement..................................26
Limit Control Switch ......................................................26
Louver Vane Adjustment ..............................................26
Combustion Air Pressure Switch .................................26
Flame Roll-out Switch ..................................................26
Service..........................................................................26
Start-Up and Performance Checklist ...........................27
LF25
30,000 to 400,000 Btuh Series
Table Of Contents
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.
Note - Unit heaters are designed for indoor use only.
RETAIN THESE INSTRUCTIONS FOR FUTURE REFERENCE
WHAT TO DO IF YOU SMELL GAS:
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.
Do not try to light any appliance.
Leave the building immediately.
Do not touch any electrical switch; do not use
any phone in your building.
Immediately call your gas supplier from a
neighbor's
structions.
If you cannot reach your gas supplier, call the
fire department.
FIRE OR EXPLOSION HAZARD.
Failure to
ly could result in serious injury, death,
or property damage.
WARNING
Be sure to read and understand the
structions in this manual.
ation, service or maintenance can cause
serious injury, death or property damage.
