Gas Furnace Problem


  #1  
Old 10-14-02, 09:17 AM
Lon Winters
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Gas Furnace - won't click on -

I would appreciate any help on this one -

Turning up the thermostat or shorting the contacts on the unit produce nothing. There is power going to the unit, checked that.

What is the next likely source of the problem? My guess is that it has something to do with the module or a component of the module that the thermostat connects to.

I can read voltages and have the schematic, but even at that point it's a little outta my league - so if I can narrow it down, and replace a part or two I wouldn't mind. And, its hard to find someone to work on this thing as its in the crawlspace!

Other info: Consolidated/Quattro brand, honeywell parts. Age, unknown, electric ignite. It worked 2 weeks ago, so all the fans and burners are most likely not the problem.

Thanks!
 
  #2  
Old 10-14-02, 01:05 PM
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Hello Lon Winters. Welcome to our Heating and Cooling forum and the Do-It-Yourself Web Site.

I'm not exactly sure which type of electronic ignition system this unit has. Is it a sparking ignitor which lites a pilot? Or does it have a glowing hot surface ignition? Below is a summation of possible causes and cures for both type systems. Hope it helps.

Electronically operated and controlled appliances often require several tests on several componets to determine the exact cause of a problem. The procedures and methods vary and at times can become rather complexing. Therefore, be advised that only your heating contractor may be able to resolve the problem.

If the pilot lighting system has an electronic sparker that lites the pilot flame, and there is no sparking, the sparking element and or electronic module are the most likely defective parts. I would suggest you clean the sparker and pilot assembly first and retest.

Also check for a good electrical connection, etc. to the sparking device, spark module and the pilot flame sensor, if the pilot flame appears and is heating the sensor element.

The wire that should be cleaned is usually green in color and attached to the sparker module. The other end of this wire will be attached to the furnaces frame.

Be sure the terminal connection is clean and free of any rust and or corrosion. Wire brush or use sanding paper to clean the effected area, then reattach the terminal end exactly as you found it prior to removal.

The pilot flame sensor is not the same as a thermocouple. It's a true flame sensor that sends a signal the main electronic sparking module that a pilot flame is established. The pilots flame will be heating this element directly.

Once the signal is received at the main spark module, the main module allows the gas valve to open, sending gas to the burners. If the signal is not sent or recieved, the module will not allow the burners gas valve to open. Therefore, either no burner flames or the burner flames will cycle on and off intermittently.

Below is a list of some of the possible problems and solutions for heating appliances using a Glow Bar type ignition system. Pick and choose which type, problem or condition applies to the heating appliance you have.

Defective Glow Coil:
The glow coil may glow but just be too weak to allow current to continue to flow to the magneto coil and other parts it supplies current to. Replacing the Glow Bar {Hot Surface Ignitor} may solve the problem.

The main computer circuit board also controls and regulates functions of the heater. It too may have a defective componet.

Defective Solenoids:
The solenoids are on top or inside the body of the gas valve body. Solenoids also supply voltage to a glow bar {if applicable} gas to the pilot flame {if applicable} main burner gas and or other parts and componets of the entire electrical loop.

Defective Gas Valve:
Remove entire unit as an assembly. Take the entire assembly to your local appliance parts store for testing. Gas valves are not repairable. Replacement is the only option, if defective.

CAUTION:
Do Not attempt to repair the gas valve!
This is a NON repairable item!

The ideal method for determining if either the solenoid, gas valve, gas valve parts, electronic parts or componets, circuit boards or other componets are defective, is to remove the item or items.

Take the entire assembly and or componets to the local retail appliance parts store or heating appliance dealers retail store and have the entire assembly and or parts inspected and or tested, as needed.

Flame Sensor:
This part is located on the burner or near the pilot assembly. If it's defective, it will cause the glow coil to not function or cause the problem your describing.

The flames sensor element, is the part which the pilot flame heats once a pilot flame is established. Cleaning the flame sensor element may solve the problem.

Not all furnaces have a seperate flame sensor element. If your heating is equipped with one, insure the flame sensors element is connected securely and correctly in the pilot assembly, is being heated by the pilots flame, is properly connected to the computers modual or spark modual and that either or both modual is in turn grounded well and correctly.

FYI:
The do-it-yourself person can test some of these parts yourself using a voltage tester, continuity tester or an ohm meter. However, do not rely totally and solely on any of these tests to determine if the part or componet is functioning correctly.

TIP:
The only positive proof any part is functioning correctly, is to carefully remove the part or parts you suspect to be the potential culprit, and have the local appliance parts store person test it or check it. Appliance parts dealers carry replacement parts for all appliances and are listed in the phone book under appliances.

Suggestions:
Read the manufacturers online web site for product information, problem solving methods, disassembly, reassembly methods, repair proceedures and instructions, pictorials and schematics, which may be available online.

CAUTION:
Be absolutely positive the electrical power is turned OFF before attemping ANY repairs!

Read the RECENT postings & ARCHIVES, within this forum, for other postings on this topic and the replies offered.

Regards & Good Luck
Gas Appliances Forum Moderator
Tom_Bart...Fast, Fair, Friendly & Highly Efficient.....
Energy Conservation Consultant & Natural Gas Appliance Problem Diagnostics Technician.
 
  #3  
Old 10-14-02, 06:14 PM
Lon Winters
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Thank you for the comprehensive reply -

It does sound like the electronic module, which I will have tested and replace if needed. If that isn't it I will surely get one of the pros in here. Thanks again!
 
 

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