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Gas Supply 

Check all local codes for requirements, especially for the size and type of gas supply line required. On natural gas lines less than 
15” (380 mm) long, use 1/2” tube; on longer runs, use 3/4” iron tube or equal. On LP gas lines, consult LP gas supplier. 

Installing a New Main Gas Shutoff Valve 

Each appliance should have its own manual gas shutoff valve. A manual main gas shutoff valve should be located in the vicinity 
of the furnace. Where none exists, or where its size or location is not adequate, contact your local authorized installer for 
installation or relocation. 

Compounds used on threaded joints of gas piping must be resistant to the action of propane (LP) gas. The gas lines must be 
checked for leaks by the installer. This should be done with a soap solution watching for bubbles on all exposed connections, 
and if unexposed, a pressure test should be made.  Repair all leaks prior to operating the furnace. 

Never use an exposed flame to check for leaks. Appliance must be disconnected from piping at inlet of control valve 
and pipe capped or plugged for a pressure test.  Never pressure test with appliance connected; the control valve will 
sustain damage! 

A gas shutoff valve and ground joint union should be installed in the gas line upstream of the gas control to aid in servicing. It is 
required by the National Fuel Gas Code that a drip line be installed near the gas inlet. This should consist of a vertical length of 
pipe tee connected into the gas line that is capped on the bottom in which condensation and foreign particles may collect. 

The use of the following gas connectors is recommended: 
– ANSI Z21.24 Appliance Connectors of Corrugated Metal Tubing and Fittings, CGA 6.10 
– ANSI Z21.45 Assembled Flexible Appliance Connectors of Other than All–Metal Construction. 
The above connectors may be used if accepted by the local codes or authority having jurisdiction. 

Pressure Testing of the Gas Supply System 

1.  To check the inlet pressure to the gas valve, a plugged tapping, accessible for test gauge connection, is provided on the 

gas valve (Figure 8). 

2.  The appliance and its individual shutoff valve must be disconnected from the gas supply piping system during any pressure 

testing of in excess of 1/2 psig (3.5 kPa). 

3.  The appliance must be isolated from the gas supply piping system by closing its individual manual shutoff valve during any 

pressure testing of the gas supply piping system at test pressures equal to or less than 1/2 psig (3.5 kPa). 

Attention

:  If any of the above procedures results in pressures in excess of 1/2 psig (14” w.c., 3.5 kPa) on the appliance gas 

valve, it will result in a hazardous condition. 

High Altitudes (US Only) 

For altitudes/elevations above 2,000 feet (610 m), ratings should be reduced at the rate of 4 percent for each 1,000 feet (305 m) 
above sea level by reducing the manifold pressure at a rate of 8% on the gas supply. Maximum altitude allowed for installation is 
5,500 feet (1680 m). 

High Altitudes (Canada Only) 

The appliance is tested according to CGA 2.17 M91 for installation between 0 and 4,500 feet (0 and 1370 m) altitude. For 
altitudes/elevations above 2,000 feet (610 m), ratings should be reduced at the rate of 4 percent for each 1,000 feet (305 m) 
above sea level by reducing the manifold pressure at a rate of 8% on the gas supply. Maximum altitude allowed for installation is 
5,500 feet (1680 m).  

High Altitude Adjustment 

Based on the altitude of the installation site, reduce the manifold pressure specified in the “Technical Data” chart and as shown 
in the table below: 

Altitude 

Manifold Pressure 

Reduction Rate 

0-2,000 ft 

0% 

2,000-3,000 ft 

8% 

3,000-4,000 ft 

16% 

4,000-5,000 ft 

24% 

5,000-5500 ft 

32% 

First Firing the Furnace 

Start the furnace following the instructions given in the “Operating Instructions“.  The initial pilot lighting may be difficult due to air 
trapped in the gas lines.  During initial firing of the furnace, residual manufacturing grease will bake-out and smoke will occur 
which is not a health danger. To prevent nuisance and operation of fire alarms, ventilate the room for the first two hours of 
operation. 

 

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Summary of Contents for 2903511

Page 1: ...losion may result causing property damage personal injury or loss of life Williams Furnace Co 250 West Laurel Street Colton CA 92324 U S A MODEL Natural Gas Only 2903512 MODEL Propane Gas Only 2903511...

Page 2: ...d repair should be done by a QUALIFIED SERVICE TECHNICIAN The installation must conform to local codes or in the absence of local codes the installation must conform to the National Fuel Gas Code ANSI...

Page 3: ...lified service technician to inspect the furnace and to replace any part of the control system and any gas control which has been under water Safety Information for Users of LP Gas Propane LP Gas is a...

Page 4: ...is a good safety measure under any condition If at any time you do not smell the LP Gas odorant and you should assume you have a leak Then take the same immediate action recommended above for the occa...

Page 5: ...th CAN CSA C22 2 No 3 Installations in the State of Massachusetts All installations in the State of Massachusetts must use the following requirements when installing maintaining or operating direct ve...

Page 6: ...ne of the terminal 18 inches 46 cm minimum E Clearance to unventilated soffit 12 inches 30 cm minimum clearance to vinyl soffit 36 inches 90 cm minimum F Clearance to outside corner 12 inches 30 cm mi...

Page 7: ...ipe in the wall through the hole provided in the support bracket Place the round adhesive gasket around the hole so that the air pipe remains in its position 6 Attach the supporting bracket with the s...

Page 8: ...ace 14 Position the vent cap and attach it with the screws Figure 7 15 Connect the female end of the three prong plug to the furnace connection on the bottom of the furnace 16 Connect the gas supply l...

Page 9: ...s pressure and settings Minimum Burner Pressure Setting a Set LOW burner capacity by pressing button Z2 b Connect a micro manometer to the test gauge B Figure 8 c Rotate the internal screw D Figure 8...

Page 10: ...he inlet pressure to the gas valve a plugged tapping accessible for test gauge connection is provided on the gas valve Figure 8 2 The appliance and its individual shutoff valve must be disconnected fr...

Page 11: ...pressure must be checked both in Hi and Lo input The gas manifold pressure must be as shown in the Technical Data Differences of plus or minus 0 1 in w c are accepted If the Hi or Lo gas manifold pres...

Page 12: ...SSURE SWITCH FLAME SENSOR SPARK IGNITER 2 pcs COMBUSTION BLOWER MOTOR FLAME VIEW LAMP GREEN LAMP SB TR Z1 Z2 Z3 Z8 Z9 L1 L2 GND LOCK OUT LAMP RED LAMP TRANSFORMER 120 24 V RESET AND SUMMER WINTER SWIT...

Page 13: ...ot try to light any appliance Do not touch any electric switch Do not use any phone in your building Immediately call your gas supplier from a neightbor s phone FOR YOUR SAFETY READ BEFORE OPERATING W...

Page 14: ...rnace will operate in heating mode according to the thermostat and or clock s program When the button is down the appliance will provide ventilation MIN MAX BUTTON For faster heating keep this button...

Page 15: ...solution and correct any leaks prior to operating the furnace The HI and LO pressures must be adjusted as explained above Never try to adjust them independently from each other Checking Removing and...

Page 16: ...s 4 Check air flow switch 5 Clean and check exhaust flue pipe and air intake pipe 6 Check for gas leaks on all connections 7 Check and adjust gas pressure Check red O Ring Gasket NRNG003 If it is dama...

Page 17: ...tion Programmable day blocks 1 2 3 4 5 Monday Friday 1 2 3 4 5 6 Monday Saturday 1 2 3 4 5 6 7 Monday Sunday 6 7 Saturday Sunday KEY A On Off Switch Pos I The appliance is controlled by the room therm...

Page 18: ...7 Figure 10 D a triangular shaped indicator proceeds one day at a time Number 1 stands for Monday number 2 stands for Tuesday etc C To set the time press the Hour Selector button h Figure 10 E to set...

Page 19: ...ght Press the Program Selector Figure 10 C button and select the program to be cancelled B Simultaneously press the Program Selector Figure 10 C and SKIP button Figure 10 G for at least 2 seconds The...

Page 20: ...nd summer winter switch The switch is closed if there is no ignition block 4 Check Z2 Hi Lo flame and fan speed switch Button down Minimum velocity Button up Maximum velocity TROUBLESHOOTING STEP 2 Po...

Page 21: ...wirings and connections If they are OK replace the thermostat STEP 4 8 Check Z9 Room thermostat Close the thermostat by a clockwise rotation 9 Check M1 Overheat thermostat automatic reset The thermos...

Page 22: ...e the transformer Point 14 EV1 Valve closed during ignition Z2 down Check wirings connections and voltage If everything is OK replace the gas valve Point 15 RP7 No spark during ignition Check electrod...

Page 23: ...inter Switch Part Number P332571 Z8 Z3 Timer and Manual Program Mode Switch Part Number P332570 Z2 Hi Lo Flame and Fan Speed Switch Part Number P332569 SF SB Green and Red Lamps Part Number P332538 P3...

Page 24: ...ion Blower Motor Part Number P332514 M1 Overheat Thermostat Part Number P332522 M2 Fan Thermostat Part Number P332496 Fan Blades 4 pieces Part Number P332572 Left P332638 Right M Fan Motor 2 Pieces Pa...

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