Have a Goodman 80% efficiency furnace inside our home, installed in a new home that is 2 years old and still under warranty. The igniter will not stay lit long enough to ignite the gas. The process starts blower comes on, click, igniter lights, igniter goes out, you hear the gas released but obviously does not ignite the burners. It cycles three times and then goes into shutdown mode. After interrupting the power and attempting to start again, cycle repeats with no ignition. The LED only flashes 1 time indicating the shutdown mode.

I have had a service person out and after he checked all the switches and bypassed all parts, indicted it was a faulty circuit board. His return trip to install the circuit board was not successful. The furnace fired once and then back to the cycling. He then replaced the gas valve. At the time this appeared to resolve the issue.

Two weeks later, we are having the same issue as described above; blower comes on, igniter lights/goes off, gas released, repeat 2 more times. Have called the service repair. He has indicated that he does not know why this is happening.

Have already "invested" $335 in this event. Any additional thoughts would be greatly appreciated.

Exact model number?

Model GMS8, GMS80704BNBC to be exact.

As a note if interest. For giggles after sitting overnight, I turned it on this morning. It fired up as it should, ONCE. After the room came to temp and it shut off, it began cycling again. I have arrived home this afternoon and again decided to give it a try. Ta da... fired up again, worked as it should. We'll see if it cycles back after it brings the room to temp.

The temp here in Winston-Salem is around 45 degrees as it was last night. As the unit is in a crawl space on the second story, could the cold have something to do with it?

Thanks.

FYI your warranty. I hope you were not charged for parts!

http://www.goodmanmfg.com/Portals/0/pdf/CB-GMS8.pdf

Note: First of all if you were charged for repair labor and the unit is not fixed then you are entitled to a refund if the service provider will not return to fix the problem. His labor warranty has to be longer than 2 weeks so stick to your guns and have him fix the problem correctly OR tell him you are entitled to your money back since he has no idea what he is doing except to replace parts.

Do you know how many flashs/blink codes your circuit board is flashing/blinking as a trouble code? This information would be nice since it will direct us in discovering what the problem could be. Usually when the furnace is turned on and the unit fails to operate properly the furnace failure will set a blink/flash code that can be seen on the circuit board trouble/operating light. See page 29 and 30 of the following furnace install/trouble shoot document for your furnace and tell us what the code is. This will help us further assist you. Also keep a copy on your computer for your future reference. As well as a copy of your warranty as posted above.

http://www.alpinehomeair.com/related/Goodman%20GMS8%20GDS8%20Install%20Instructions.pdf

Once you post the trouble code we can isolate the problem.

You also mentioned
As the unit is in a crawl space on the second story, could the cold have something to do with it?

A crawl space on the second story? Usually the crawl space is under the house? Can you explain better? The reason for my question on this is that unconditioned crawl space installs can have more terminal/wiring problems due to corrosion from moisture and the corrosion/moisture can also have negative impact on equipment grounding and flame sensing controls. Also the 12 pin plug in connector will corrode on the circuit board etc. Post back after your reading of the install instructions and your findings on the trouble code.

First of all, thanks for the response. These type of situations happen to my family all the time... "Just the Clark Luck" we call it...

We have not had the discussion of his return trip. We did not have to pay for the parts directly. There was a "handling fee" and labor charge, but nothing for the parts.

The LED is only flashing one flash. Per the troubleshooting chart "Furnace lockout due to an excessive number of ignition attempts". No other flashes.

Sorry for the confusion on the "crawl space". The furnace is located on the second floor of our house in an area that one might consider an unfinished attic. One can see the insulation that covers the walls in the bedroom and activity room once inside. You can also see the the rafters for the roof. A consistent environment is not kept.

As a note from my previous post. After the proper operation when I arrived home, the second time did again not work. We had plans this evening and were out of the house from 7p-11p during this time I had the t-stat turn off so it would not cycle every hour. Once we got home, I turned it back on and again, it operated properly. It has yet to get to temp, but I presume it will do the same thing. Once the t-stat requests heat, it will just cycle.

Thanks again for any advice.

To start I would like to mention I had put the wrong address in the second link I provided above and it is changed now to the proper one. Try the link again as posted below and look on page 29 for the exact meaning and description of your furnace problem. Sorry about my confusion.

http://www.alpinehomeair.com/related/Goodman%20GMS8%20GDS8%20Install%20Instructions.pdf


One simple item you might try first to do is to clean the flame sensor. This item seems to cause many problems with all the new style furnaces that use them. It is a rather simple item to do and by cleaning the sensor it will eliminate that problem from the possibilitys. You can use steel wool,sand paper,or Scotch Brite pad but you need to be sure it is clean. (Note it might look clean when you first look at it but do not let this fool you. Most of the time the coating is clear in nature that accumulates on the sensor and looks clean to the eye. Just clean it good to be sure it is clean and any clear coating is removed.) If the sensor is located near the ignitor do not damage the ignitor. They are fragile and will be broken easily.


Here is a link to a parts diagram for your furnace. Look at page 10 item number 61 for a picture of the sensor and where it is located. Also note the position/location of the ignitor number 11. The ignitor is what you want to stay away from when cleaning the sensor. I believe one 1/4 inch screw holds the flame sensor rod in place so it can be removed if you want to have better access for cleaning. Just make sure you put it back exactly as removed. Below is the link for the parts diagram for your furnace and I recommend you keep a copy of all three links I provided on your computer for future reference.

http://igate.northernplumbing.com/partsbreakdowns/GoodmanMfg/GMS8.pdf

Once the flame sensor has been cleaned turn the power back on to the furnace and let it run as you would for normal operation and see if this cleaning solved the problem. Post back with the results of your first adventure into the realm of a furnace repair person.


Below is a example of a flame sensor and how the metal part it is being cleaned. The picture might not be exactly the same as what you have on your furnace but it is for reference only.

Cleaning successful. Easily removed. Used a 3M pad that says replacement for "0" Steel wool. There appeared to be a noticeable film on the end of the sensor. Cleaned and replaced. Powered furnace back up. Again it fired the first time. Ran to temp. Same issue. The second time it attempts to ignite, 3 attempts and then into lockout mode.

As a side note, if the pad was not abrasive enough, what grit sand paper should be used, 220 maybe?

Forgot.. LED still blinks 1 flash.

OK just for the heck of it use sandpaper and make sure it is clean. 220 grade will work if you have it. Then try the furnace again and see what it does.

After this cleaning if it works great but if not the next step will see if you have a weak limit control. Post back with the results of the latest cleaning of the flame sensor.

Cleaned with 220. Still not luck. No ignition and still 1 flash on the LED.

I have encountered this situation a few times, and the culprit proved to be the pressure switch. Enough voltage was passing to convince the circuit board that it was closed, but as other relays on the board were being activated, the pressure switch could not support the control current. A check of the continuity through the switch while engaged revealed measurable resistance.

OK in the blower compartment there is a auxilery limit control. It is set at a very low temp of 125 degrees. This is the second item that could be causing a problem. I want you jump the limit control or in other words bypass it. If this item is out of range it is possible for it to easily overheat and cause the board to lock out like it has been doing. One other question is this furnace installed in a upright position length wise or is it in the horozontal position. See this link below for the item you need to jump out. Jumping out means to bypass this small disc control. It can be done with a jumper wire or by the two wires being electrically tied together. This way the control is out of the system for test purposes only. Post back with results. (note while this test is somewhat unlikely to be the cause I would like it to be tested just to be sure it is not causing the problem)
See the image for location on the diagram listed below.
Page 6 image 1 item number 31

http://igate.northernplumbing.com/partsbreakdowns/GoodmanMfg/GMS8.pdf

The unit is installed as the picture displays in the parts manual.

A question concerning by passing the control. I do not have a clip bypass. They also, as I am sure you are aware, have clips on the end of them. Would it be possible to use a multimeter to bridge the connectivity?

As long as the two wires are removed from the limit control and electrically connected together OR a aligator clip and wire jumper is used it does not make a difference what you use. Just make sure the connection is tight because you will be putting the door back on the blower compartment to test the furnace and you would not want the wires to come loose and short to ground while the blower is running moving the air around..

I know you probably don't have a monometer so try this test, the pressure switch must be in a open position when the furnace starts 5 seconds after the inducer motor starts jump out the two terminals at the pressure switch and see if it remains running, Let me know if it does you may need a pressure switch but you have to check the inducer motor is pulling enough inches of water column to pull the press switch in and sometimes behind the inducer motor there is a gasket that comes out to reduce the vacumn. Cgeck and let me know. Mikie D.

Looks like I am going to have to make a cable to bypass the switch. HD, Lowe's, RS, only had clips. No pre-mades. What gauge wire should be used. I have looked on the intranet and found models that have 18, 20, and 22 gauge wire.

I believe a 1/4 inch dubble male terminal adapter will work OR a permade jumper with insulated aligator clips on both ends will work. The limit is in the 24 volt control circuit I believe so the wire for testing purposes need not be a heavy gauge. In mt service bag I always carr a few of these to jump out circuits. Usually Home Depot or Lowe's has permade jumpers in the electrical department hanging on a card/blister pack.

Checked bot HomeDepot and Lowe's. Only had the connectors. Made my own with a piece of 18 gauge wire. Attached newly created jumper to each end of the wires going to the switch. Powered on the furnace. No luck. Same situation.

Very strange indeed. Since the service man already replaced the circuit board which did not help and then replaces the gas valve which then allowed the furnace to operate normally for two weeks before the problem started again I have just about exhausted what I can tell you to do from here since the only part you can check next is the pressure switch mentioned by KC13 in his post above.

I did not mention the pressure switch before since I figured you did not have a electric meter to measure resistance across the contacts when the small furnace draft fan is in operation. If you have a meter or can borrow/buy one you can test the pressure switch which is part number 41 on page 4 of this link.

http://igate.northernplumbing.com/partsbreakdowns/GoodmanMfg/GMS8.pdf

The pressure switch is attached to the furnace and has a plastic tube attached to it.

Checked bot HomeDepot and Lowes. Only had the connectors. Made my own with a piece of 18 gauge wire. Attached newly created jumper to each end of the wires going to the switch. Powered on the furnace. No luck. Same situation.If you jumper the pressure switch leads before the draft inducer starts, the system will fault out, assuming the p/s is stuck closed. You must initiate a heating cycle, wait for the inducer to reach full speed, then jumper the wires together.

Very strange indeed. Since the service man already replaced the circuit board which did not help and then replaces the gas valve which then allowed the furnace to operate normally for two weeks before the problem started again I have just about exhausted what I can tell you to do from here since the only part you can check next is the pressure switch mentioned by KC13 in his post above.

I did not mention the pressure switch before since I figured you did not have a electric meter to measure resistance across the contacts when the small furnace draft fan is in operation. If you have a meter or can borrow/buy one you can test the pressure switch which is part number 41 on page 4 of this link.

http://igate.northernplumbing.com/partsbreakdowns/GoodmanMfg/GMS8.pdf

The pressure switch is attached to the furnace and has a plastic tube attached to it.

I do own a digital multimeter (Christmas present from a friend who always looked out for me with tools.. ). So here goes the questions... :D

Have AC/DC switch: presume AC
Dial has the following areas: F, V, A, O(with feet): presume the later (O with feet)
Settings in ohm; 20M, 2M, 200K, 20K, 2K, 200: Not sure here, or does it matter. I presume any number is not good.

When you indicate to measure when the small draft fan is on. I presume this is the first fan I hear when the unit begins the heating process?

20 ohm fine, test all limit switches firsy when you touch leads together meter should read 0 that's continuity take wires off limits and test all should read zero. Now the pressure switch should read open not zero,Then start furnace and 5 sec after first draft motor starts ,test press switch and should close or zero meaning made then let us know

20 ohm fine, test all limit switches firsy when you touch leads together meter should read 0 thats continuity take wires off limits and test all should read zero. now the pressure switch should read open not zero,Then start furnace and 5 sec after first draft motor starts ,test press switch and should close or zero meaning made then let us know

Pardon the rookie question, 20 ohm meaning 20m? If so, results:

Test with Leads on Switch = 0
Test wires attached to switch = 0
Test switch with no wires = no change in digital reading

Test switch after power on of furnace (no wires attached, correct?) returns to zero after approximately 2 seconds.

Standard operation?

It seems as though you are not reading anything beyond the most recent post. Good luck.

Don't mean to be rude, but I have read all the posts. Your second post concerning the timing of jumpering the pressure switch came as were were discussing the aux limit control jumpering. Since that time, I the discussion has migrated to the pressure switch. Specifically, checking for resistance on the pressure switch. Does the last test satisfy the question about the functioning of the switch? If not, then I presume the draft inducer is the first initiated process after the t-stat calls for heat?

Sorry for all the rookie questions but it is frustrating to have this when our service is stumped about the issue.

Again, thank you all for your generous assistance.

Finally got a call from the service man. He contacted the Goodman company and they want to have the pressure checked from the gas line into the furnace. Goodman indicated that the newer models of gas valves need less pressure than their older counter parts. The service man is coming out tomorrow. I'll post back with the results.

Thanks again for all the responses.

Are you on Natural gas or propane?

Natural gas.

Your quote (The igniter will not stay lit long enough to ignite the gas. The process starts blower comes on, click, igniter lights, igniter goes out, you hear the gas released but obviously does not ignite the burners.)

It will be interesting to see how this works out.

Well what do you know. The service guy came back today and the Goodman contact was correct. The gas pressure was set to high. He throttled it back to the appropriate pressure and it worked. He tried it multiple times just to make sure. So, it is working... for now.

Now the interesting question... Did we really need to replace the board and gas valve? Guess we'll never know.

Thank you all for your information and assistance.

I highly Doubt it I can tell you how many time techs set up new and old furnaces and never put there manometers on them. Mikie D

Glad you got it fixed. Sorry I wasn't there to check pressures. This is common. High pressure on newer vavles will not let valve open(sometimes letting them open a few seconds too late, after igniter has shut down).

I have had a service person out and after he checked all the switches and bypassed all parts, indicted it was a faulty circuit board. His return trip to install the circuit board was not successful. The furnace fired once and then back to the cycling. He then replaced the gas valve. At the time this appeared to resolve the issue.


When he replaced the gas valve he did not do what servicemen are supposed to do and adjust the gas pressure as part of the service. You always check and adjust the gas pressure as part of the service and check out or when replacing the gas valve.

BTW It does not make a difference if it is a old or new gas valve as far as the pressure goes. The correct operating pressure is listed on the furnace information tag along with the model numbers and you always adjust to that pressure since that is what determines the firing rate/BTU's per hour heat capacity.

When standard routine's are not followed this is what happens and you had to pay the piper for his mistakes. At least you got it going.