Lennox LGH420 User'S Information Manual Download Page 4

Page 3

Placing Unit Into Operation

 

WARNING

Danger of explosion and fire. Can cause
injury or product or property damage.
You must follow these instructions ex­
actly.

Gas Valve Operation for White Rodgers 36H54 and
Honeywell VR8205Q/VR8305Q (figure 1 and 2)

WHITE RODGERS 36H54 GAS VALVE

Two-Stage

FIGURE 1

LOW FIRE

ADJUSTMENT

HIGH FIRE

ADJUSTMENT

INLET

PRESSURE

TAP

MANIFOLD

PRESSURE

TAP

GAS VALVE SWITCH SHOWN IN

 ON

 POSITION.

HONEYWELL VR8205Q/VR8305Q SERIES GAS VALVE

GAS VALVE KNOB IS SHOWN IN 

OFF

 POSITION

FIGURE 2

LOW FIRE

ADJUSTMENT

HIGH FIRE

ADJUSTMENT

INLET

PRESSURE

TAP

MANIFOLD

PRESSURE

TAP

1- Set thermostat to lowest setting.

2- Turn off all electrical power to appliance.

3- This appliance is equipped with an ignition device

which automatically lights the burner. Do 

not

 try to

light the burner by hand.

4- Open or remove the heat section access panel.

5- Turn gas valve switch to 

OFF

. See figure 1. On

Honeywell VR8305Q gas valves, turn knob on gas
valve clockwise 

 to 

OFF

. Do not force. See

figure 2.

6- Wait five (5) minutes to clear out any gas. If you then

smell 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 appliance.

10- Set thermostat to desired setting.

11- The ignition sequence will start.

12- If the appliance does not light the first time (gas line

not fully purged), it will attempt up to two more
ignitions before locking out.

13- If lockout occurs, repeat steps 1 through 10.

14- If the appliance will not operate, follow the

instructions “Turning Off Gas to Appliance” and call
your service technician or gas supplier.

Turning Off Gas to Unit

1- If using an electromechanical thermostat, set to the

lowest setting.

2- Before performing any service, turn off all electrical

power to the appliance.

3- Open or remove the heat section access panel.

4- Turn the knob on the gas valve clockwise 

 to

“OFF”

. Do not force.

5- Close or replace the heat section access panel.

 

WARNING

Danger of explosion. Can cause injury or
death. Do not attempt to light manually.
Unit has a direct spark ignition system.

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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