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STARTUP AND OPERATIONAL CHECKOUT

Do not use this furnace as a construction heater.
Use of this furnace as a construction heater
exposes the furnace to abnormal conditions,
contaminated combustion air and the lack of air
filters. Failure to follow this warning can lead to
premature furnace failure and/or vent failure which
could result in a fire hazard and/or bodily harm.

The automatic gas valve controls the flow of gas to

the main burners. The ignition system control switch built
into the automatic valve body has 2 positions: "OFF" and
"ON" (Figure 13). To shut off gas manually:

Rotate

 switch

from "ON" to "OFF" position. When in "OFF" position, the
main burners are extinguished.

This furnace is equipped with an automatic hot-

surface ignition control and does not require the manual
lighting for furnace operation.

Figure 13

GAS CONTROL DIAGRAM

Do not attempt to manually light the burners.
Failure to follow this warning can lead to electrical
shock that could result in bodily harm.

After the ductwork connections have been made, gas

piping and electrical wiring completed and the furnace
has been properly vented, the unit should be started and
adjusted for proper operation. Check off the following
steps as they are completed.

1. Be sure all electrical power is OFF.
2. Check all wiring using proper wiring diagram on

inside of the control box cover.

3. Turn ON the electrical power.
4. Set the 

gas control knob 

in the "ON"

 position.

5. Set the thermostat above room temperature.
6. The 

ignitor will spark and the main burner

 will ignite.

Figure 14

TYPICAL FLAME APPEARANCE

(Main Burners)

7. Recheck for leaks in the manual shut off valve, gas

control valve and gas connections using a soap
solution.

Never use an open flame when testing for gas
leaks! Use of an open flame could lead to a fire or
explosion.

Many soaps used for leak testing are corrosive to
certain metals. Piping must be rinsed thoroughly
with clean water after leak check has been
completed.

Manifold  Pressure  Adjustment:

Turn OFF the gas and electrical before

preceeding!

 Remove the manifold pressure tap pipe

plug from the gas valve (Figure 13 outlet pressure tap)
and install a pressure tap and connect it to a manometer.
Turn on the gas and electrical supplies, then measure the
manifold pressure 

with the furnace in operation.

20541501

 

Issue 0240

 

      Page 18 of 26

Summary of Contents for MPGA 050 B3

Page 1: ...APPLICATION GUIDE GAS FURNACE Fit s All 80 English 02 2004...

Page 2: ......

Page 3: ...and liquids in the vicinity of this or any other appliance Installation and service must be performed by a qualified installer service agency or the gas supplier Installation by an unqualified person...

Page 4: ...or the detection of leaks to check all connections as specified in The Gas Connection section on page 16 of these instructions 6 Always install furnace to operate within the furnace s intended tempera...

Page 5: ......

Page 6: ...s in place or A C evaporator in place When operating the furnace in the heating mode the static pressure and the temperature rise supply air temperature minus return air temperature must be within tho...

Page 7: ...FURNACE WIRING SPECIFICATIONS 20541501 Issue 0240 Page 5 of 26...

Page 8: ...lson Boulevard Arlington VA 22209 or the Canadian installation codes obtainable from Canadian Standards Association 178 Rexdale Boulevard Etobicoke Ontario Canada M9W 1R3 This furnace is designed for...

Page 9: ...e furnace is to be installed in a crawl space consult local codes Use of a concrete pad 1 to 2 thick is recommended If the furnace is to be suspended from the ceiling it will be necessary to use steel...

Page 10: ...on of gas proper venting and maintenance of ambient temperature at safe limits under normal conditions of use The furnace shall be located so as not to interfere with proper circulation of air In addi...

Page 11: ...000 60 000 80 000 100 000 120 000 140 000 160 000 100 100 100 100 120 140 160 12 12 12 12 13 14 15 EXAMPLE 50 000 Btuh Furnace 10 000 Btuh Water Heater 60 000 Btuh Total Input 12 Dia Round Duct If ve...

Page 12: ...n of rectangular air ducts must not be less than 3 inches Each opening must have a free area of not less than one square inch per 2 000 Btu per hour of total input of all appliances within the Confine...

Page 13: ...re should be at least one 90 air turn between blower and return grille Further reduction in sound can be accomplished by installing acoustical air turning vanes and or lining the inside of the duct wi...

Page 14: ...ace Under no circumstances should the air flow be such that cooled conditioned air can pass over the furnace heat exchanger This will cause condensation in the heat exchanger and possible failure of t...

Page 15: ...use of one of the following auxiliary draft inducer kits Table 4 AUXILIARY DRAFT INDUCERS Vent Kit MFR Model Furnace Input Field Controls Co SWG 4G 50000 75000 100000 or 125000 Tjernlund Products Inc...

Page 16: ...ssure switch tubing from the combustion blower 3 Remove the four 4 screws that secure the combustion blower adaptor plate to the flue collector box taking care to support the blower assembly so that i...

Page 17: ...ny other gas fired burning appliance to their previous conditions of use ELECTRICAL CONNECTIONS When installed the furnace must be electrically grounded in accordance with local codes or in the absenc...

Page 18: ...ifically for the detection of leaks to check all connections A fire or explosion may result causing property damage personal injury or loss of life The furnace and its individual shutoff valve must be...

Page 19: ...20541501 Issue 0240 Page 17 of 26 THEORY OF OPERATION...

Page 20: ...g completed and the furnace has been properly vented the unit should be started and adjusted for proper operation Check off the following steps as they are completed 1 Be sure all electrical power is...

Page 21: ...of gas flow by using the formula provided below or Table 5 Cubic Ft Hr Number of Dial Revolutions x Cubic Foot Revolution x 3600 Time in seconds Required for Number of Timed Revolutions TABLE 5 Gas R...

Page 22: ...ifold pressure The appropriate manifold pressures based on the elevation and the heating value can be found in Table 7 TABLE 7 High Altitude Manifold Pressure Derate with standard 42 orifice Natural 5...

Page 23: ...h The furnace should be allowed to cool off before attempting to reset the switch Failure to follow these instructions could result in injury due to burns The switch located behind the burner access p...

Page 24: ...SEQUENCE OF OPERATION Direct ignition system control 20541501 Issue 0240 Page 22 of 26...

Page 25: ...This will expose both the burner and flue openings of the primary heat exchangers 6 Vacuum the length of each heat exchanger tube using a straight attachment into the burner openings and the flue ope...

Page 26: ...2 screws located in the blower compartment that secure the blower legs to the blower partition panel 7 Slide the blower forward about two 2 inches This will disengage the rear of the blower legs from...

Page 27: ...TROUBLE SHOOTING With LED Indicator Assistance 20541501 Issue 0240 Page 25 of 26...

Page 28: ...WIRING DIAGRAM 20541501 Issue 0240 Page 26 of 26...

Page 29: ...he CSA International symbols on each nameplate is your assurance that your furnace design meets nationally recognized standards for safety and performance Do not store or use gasoline or other flammab...

Page 30: ...dor of gas is present Use only your hand to adjust the gas control switch never use tools If the switch will not move by hand don t try to repair it call a qualified service technician Force or attemp...

Page 31: ...tat dial or lever to select the temperature you would like the system to maintain Fan Operation You may wish to increase your comfort by setting your system for continuous air circulation of the indoo...

Page 32: ...flashlight will be useful for these inspections Make one inspection prior to the beginning of the heating season and another during the middle Should you observe unusual amounts of any of the followi...

Page 33: ...and place back in furnace To clean a permanent filter shake filter to remove excess dirt and or use a vacuum cleaner Wash filter in soap or detergent water and replace after filter is dry Permanent fi...

Page 34: ...ner Blower Motor Blower Door Shield Top Bottom Blower Wheel Orifice Capacitor Ignitor Blower Support Leg Gas Control Sensor ELECTRICAL GROUP HEAT EXCHANGER GROUP INDUCER GROUP Access Door Primary Heat...

Page 35: ...FURNACE MARKINGS IN FRENCH CONSULT WITH YOUR DEALER OR LOCAL DISTRIBUTOR HAVE AVAILABLE THE MODEL NO AND SERIAL NO LOCATED ON THE UNIT RATING PLATE TO INSURE THE CORRECT FRENCH INSTRUCTION PACKET POUR...

Page 36: ......

Page 37: ...510 88 111 Fax 420 2 579 10 393 e mail janka janka cz LENNOX DISTRIBUTION MOSCOW Tel 7 095 933 29 55 Fax 7 095 926 56 50 e mail lennox dist moscow co ru LENNOXSLOVENSKOs r o Tel 421 7 44 87 19 27 Fax...

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