Lennox LGH420 User'S Information Manual Download Page 1

LGH420, 480, 540, 600

©

2015

506345-02
9/2015
Supersedes 506345-01

WHAT TO DO IF YOU SMELL GAS:

FIRE OR EXPLOSION HAZARD

Failure to follow safety warnings ex­
actly could result in serious injury
death or property damage.

WARNING

Do not store or use gasoline or other
flammable vapors and liquids in the
vicinity of this or any other appliance.

Installation and service must be per­
formed by a qualified installer, ser­
vice agency or the gas supplier.

D

Do not try to light any appliance

.

D

Do not touch any electrical switch; do not
use any phone in your building.

D

Immediately call your gas supplier from a
neighbor's phone. Follow the gas supplier's
instructions.

D

If you cannot reach your gas supplier, call
the fire department.

D

Extinguish any open flames.

ROOFTOP

UNITS

READ ALL INSTRUCTIONS IN THIS MANUAL

AND RETAIN FOR FUTURE REFERENCE

See unit nameplate for manufacturer
and address.

(35, 40, 45 and 50 TONS)

D

Leave the building immediately.

Summary of Contents for LGH420

Page 1: ...t be per formed by a qualified installer ser vice agency or the gas supplier D Do not try to light any appliance D Do not touch any electrical switch do not use any phone in your building D Immediately call your gas supplier from a neighbor s phone Follow the gas supplier s instructions D If you cannot reach your gas supplier call the fire department D Extinguish any open flames ROOFTOP UNITS READ...

Page 2: ...PTIONAL BURNERS GAS VALVES 2 CONDENSER COILS 4 CONTROL BOX COMPRESSORS 4 CONDENSER FANS 6 BLOWERS FILTERS ELEVEN 16 x 25 x 2 406 x 635 x 51mm OR 16 X 25 X 4 406 X 635 X 102mm ECONOMIZER OPTIONAL ENERGY RECOVERY WHEEL OPTIONAL FILTER DRIERS LGH420 480 540 600 PARTS ARRANGEMENT LOUVERS OPTIONAL ...

Page 3: ... and protective clothing WARNING Danger of electrical shock explosion and fire Improper servicing could result in dangerous operation serious inujry death or property damage WARNING Do not use this furnace if any part has been under water A flood damaged furnace is extremely dan gerous Attempts to use the furnace can result in fire or explosion A qualified service agency should be contacted to ins...

Page 4: ...ll gas STOP Immediately call your gas supplier from a neighbor s phone Follow the gas supplier s instructions If you do not smell gas go to the next step 7 Turn gas valve switch to ON See figure 1 On Honeywell VR8305Q gas valves turn the knob on the gas valve counterclockwise to ON Do not force See figure 2 8 Close or replace the heat section access panel 9 Turn on all electrical power to applianc...

Page 5: ... Service To maintain efficiency and longevity your equipment must be serviced yearly by a qualified service technician Failure to provide proof of service can void warranty CAUTION Label all wires prior to disconnection when ser vicing controls Wiring errors can cause improper and dangerous operation Verify proper operation after servicing Servicing Filter Units are equipped with eleven 16 X 25 X ...

Page 6: ...nspect the position of the flame sensor Sensor should be centered in the path of the flame 3 Before each heating season examine the burners for any deposits or blockage which may have occurred Clean burners as follows 4 Turn off the electrical power and gas supply to the unit and open heat section access panel 5 Remove and retain two screws securing burners to the burner support See figure 5 Clean...

Page 7: ...lue box cover Clean the flue box with a wire brush as required 3 Clean the tubes with a wire brush 4 Reassemble the unit The flue box cover gasket and combustion air inducer gasket should also be replaced during reassembly Service Reminder Call a qualified service technician if the unit is inoperative Before calling always check the following to be sure service is required 1 Be sure electrical dis...

Page 8: ... maximum heating input 3 Measure the manifold pressure at the gas valves Manifold pressures should be GV1 GV3 Natural 4 0 w c LP 10 8 w c GV4 GV5 Natural 3 7 w c LP 10 5 w c 4 Turn the OPT2 switch OFF The unit will operate at minimum heating input 5 Measure the manifold pressure at the gas valves Manifold pressures should be GV1 GV3 Natural 4 0 w c LP 10 8 w c GV4 GV5 Natural 0 9 w c LP 2 6 w c FI...

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