Have a problem with my furnace, and I hope you can help me.
I switch the tstat to call for heat, and the following is what I get .....
1. The Combustion blower starts.
2. Then I hear a '' CLICK ''
3. There is a long quite moment.
4. The another '' CLICK. ''
5 Finally the main blower turns on, and all we have is cold blowing air. NO HEAT.
I never see the Igniters glow, and I only smell a hint of gas.
MAKE : LENNOX
Sounds like the ignitor is bad. there shoule be a 2 wire plug going to it. after the inducer motor starts, you can check the voltage at the 2 wire plug located under the burners. you can unpug it to check voltage or you can probe the back side of the plug with a volt meter. if you are getting 120v but it is not glowing, it is bad. you can also ohm it out while it is off.
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If its a high or mid efficiency furnace most of the time the sequence of operation goes as follows: tstat calls for heat (R&W at tstat ) ventor motor starts, pressure switch closes, spark or hsi lights pilot or main burners. main blower motor comes on. From your description of a humming noise it sounds like maybe the ventor motor is seized.
Sounds like a bad tstat. The Tstat does control the on and off of the unit.
You can check the Tstat by taking off the white wire to the tstat and turning the heat to the on position and if it still comes on you have a bad wire. If it does not come on then you have a bad tstat.
Another option is to open the furnace and look inside at the control wires and follow them back to ensure that they are not shorted together anywhere inside the unit before checking the tstat wires.
If its the control wires then follow option 1 if not follow option 2.
1.Normally people who run tstat wire pull more wires than necessary to the tstat. Because of this you can use a different one for the heat which is white on the tstat. Remember that if you use another color on this then you need to change it on the inside unit as well. Otherwise it will not work. In other words change it on one end of the line you have to change it on the other to make it work.
To check the tstat wires, use continuity. Take all the wires off the tstat and the inside unit. These are the small control wires, not the main 110 wires. Check each one against each other to see if any of them are shorted together. Be sure to write down the wire colors and the terminals that they belong to on both sides before you take them off otherwise you will have big problems...
If you do not have another wire then pulling a new wire will be the next option.
2. If this does not solve it, then its the TSTAT, Replace it.
Hope this helps.
you will need to verify voltage from the board to the inducer. If you have the installtion manual there is a flow chart for the sequence of operation of the furnace.
The basic sequence is:
1. thermostat calls for heat
2. inducer motor starts and runs for a pre-set amount of time
3. the pressure switch closes and allows for ignition trial
4. ignition is proved back to the board allowing the system to operate.
Verify 120VAC to the inducer motor upon call for heat from stat, if you have 120 at the leads that connect to the inducer and it does not start , the motor is faulty. If the inducer starts use a voltmeter across the pressure switch terminals, a voltage reading of 0 VAC will verify contact closure and ignition should occur.
The pulse furnace was under a factory recall due to breaches in the heat exchanger, unfortunately for you, the Lennox Corp. has ended the program that allowed for an allowance / furnace for replacement. To test the heat exchanger a special kit is required from lennox that will verify integrity of the heat exchanger. (If the heat exchanger seal has been comrimised the pressure switch will not prove and the igniton sequence will be interupted and cause the system to go into "lock-out" mode).I know this is probably not what you wanted to hear. Hope this helps, please list as "very helpful" if it did
Hi check out the flame senser is clean also jump ou tthe pressure switch see if it lights when you do this , igntion modul is just a box with some push on wires just get the right one the info is all on the module
Expensive is relative, service calls are never free. But if you have an idea what the problem is, you are armed against an unethical service company. Now to what you describe, could be a couple things, first let me explain the difference in fan speeds. Furnaces that both heat and cool have multi-speed blower motors. High speed is for cooling and lower speeds are for heating. The fan switch at the T-Stat turns on the high speed fan relay. The lower speed fan is turned on by either a temperature activated switch (silver box mounted on front on furnace above burners) or a time delay relay which is solid state. That being said, your problem could be a defective fan switch or one of your blower motor windings has gone bad. Most motors have 3 or 4 speeds and a technician could just change speeds and all would be good. A fan/limit switch is not so expensive that you would replace the unit. Bottom line, unless your really handy, a heating company is in your future. Good luck and please rate my answer if it was helpful to you.
POssible feed back thru tstat. This sometimes happens. Take a look at tstat disconnect w or white wire that goes to heater. Turn from heat to cool and abck and see if it does it again if not change tstat. You can get a good one at Home depot or Lowes about 20.00 easy to install Keep in touch Rus
Most of the Lennox G-16s that I have repaired were having problems with the gray Penn-Johnson Piggyback igniton control module.
This is best repaired by replacing the spark module. Sometimes it may be neccesary to replace the gas valve also. Lennox updated to a ROBERTSHAW ignition system. Honeywell can also be used.
Also check that there is no water in the pressure switch or tube.
Hope this helps.
the tstat sounds like it is not connecting the white and red terminals which is usually the heat cycle if it is a gas furnace if so to check I take tstat cover off and jump white terminal to red terminal this is the standard heat position the unit should fire the heat cycle if not a gas funace let me know what type of unit you have hope this helps