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peasoup42

@navy.mil

Goodman furnace doesn't stay lit

I've read thru these forums and tried to decipher if I have the same problem. I think this one is new...

Red light is solid (no blinky, no 'pulse', just solid light). Here are the steps the furnace does that I've noted.

1. Inducer motor turns on (approx 30 secs)
2. Gas turns on ( ), igniters ignite ( ), pretty blue flame is produced for approx 5 secs ( ).
3. Gas shuts off ( ), blower motor turns on and runs ( ), inducer motor shuts off ( ).
4. Blower motor continues to run ( ), while steps 1 thru 3 repeat ( ).

All sensors were cleaned/inspected by furnace tech. Prior issue before cleaning was the igniter glows but no flame and caused the infamous 'lock out' and could be reset and furnace would return to normal operation for a few days. Furnace occasionally will 'reset' itself and operates as advertised. Again, this blowing of cold air happens every few days.

Not sure if outside temperature is a factor, but this all happens when we get a cold snap and returns to normal operation when furnace 'thaws' out in attic. Drain from furnace to outside checked with no objects plugging the insulated 1" PVC tubing.

Going to try the jumper between 'R' and 'W' on thermostat tonight when I get home, but wanted to throw this out there in case someone had an "ah-ha" moment and recognizes this problem with a possible fix.

Thanks much...



nunya
Premium,MVM
join:2000-12-23
O Fallon, MO
kudos:12
Reviews:
·Charter
·voip.ms
·surpasshosting

A model number would help.
From my limited experience, it sounds like the flame sensor.

I don't think messing with the t-stat will help, as it's obviously calling for heat.

Just looking through one of my (newer) Goodman manuals on my desk, and it shows a steady light to be normal operation.

I would think a LV from the flame sensor would throw a code. If it was rollout, it would definitely throw a code.

Cleaning the flame sensor with steel wool is probably where I'd start.
--
If someone refers to herself / himself as a "guru", they probably aren't.


peasoup42

join:2012-12-26
Ridgecrest, CA

As many times as I was in the attic for this, you'd think I woulda grabbed the model number (prolly one of those dumbass moments). LOL Just an electronics tech, not HVAC.

I'm to assume you mean Low Voltage (LV) from the flame sensor? Should I be looking for a certain voltage off of it?

I've thought of the steel wool trick this mornin at 430am, but needed to head out to work. I shall try it and repost any improvements that result.


sergey3

join:2004-08-25
reply to peasoup42

I agree with nunya that the problem is most likely the flame sensor.
I found an article with good pictures where the person had the same symptoms and cleaning the sensor fixed it for them.

»www.hammerzone.com/archives/hvac···nsor.htm


peasoup42

join:2012-12-26
Ridgecrest, CA
reply to nunya

@ nunya..

It's a GKS90703BXAA, horizontally mounted.

I removed the flame sensor (blue wired as per schematics). It appeared pretty clean and prolly from the furnace tech doing their cleaning of sensors and adjusting of vacuum switches. But, I gave it a few good swipes anyway with some fine emery cloth as mentioned by sergey3 and the link provided just to be sure. The igniter appeared clean as well, but I didn't remove that. Had the wife fire up the furnace and it appeared bright orange and lit off the flame nicely so I reinstalled the cover.

@ sergey3...

Thanks, for the link. Much appreciated as that problem shown was indeed quite similar to mine.

The furnace itself was installed about 5 years ago when the house was built. I'm the second owner and have no history / idea of previous heating problems. If it decides to act up as usual within the next 5-7 days, I'll post any new error codes it may generate.



nunya
Premium,MVM
join:2000-12-23
O Fallon, MO
kudos:12

Glad it's going. I'd order a new one anyway. It's about $10.



tp0d
yabbazooie
Premium
join:2001-02-13
Carnegie, PA
kudos:5

Never want to use anything 'sand' on a flame sensor. Sand is glass, glass is an insulator, and when you use sandpaper on a flamerod, it leaves particles of sand on the rod. When the flame heats it, the sand melts into the pores of the steel and will insulate portions of the rod.

Always use steel wool, or a knife to scratch any buildup off the surface of the rod.

You should have your furnace serviced yearly, for exactly this issue. Flamerods typically run 1-2yrs before they need a cleaning.

Do you have an intake pipe on your furnace? If not, the 2nd pipe will increase efficiency, and will also bring in cleaner air, which will cut down on flamerod issues..

-j
--
if it aint broke, tweak it!!
currently on FiOS (kick aZZ!)


peasoup42

join:2012-12-26
Ridgecrest, CA
reply to nunya

@ nunya...

Furnace failed again this morning with the same sequence of events in my original post above. I went up in the attic to disconnect power and 'reset' the system so the wife would have heat when she got ready for work. After about 30-45 secs, I plugged the unit back in and noticed the blink from the sight glass. Now without sounding too crazy, picture this as you read it cuz this is the way I seen the sequence. It went,

Steady light on, then "Ba-blink-blink-blink" and then a steady light (no repeat of the error code) and started its cycle of turning on.

Now with that said, do I interpret that as 3 blinks and forget the 'ba', 3.5 blinks because of the 'ba', or count it as 4 blinks?!? Very confusing because of the quick, original flash from the LED followed by 3 distinct blinks.

I unplugged the system when started acting exactly in my original post and it did the same, 'ba-blink-blink-blink' when I restored power. I left it plugged in as these short bursts of heat to the exchanger was keeping the house about 68F and told the wife to turn it down to about 60F when she left for work and give the system a break.

She texted me a little while ago before leaving for work and said the furnace appears to be operating normally since she couldn't hear the induction blower cycling on and off like yesterday morning and there was constant warm air coming from the air ducts. I told her to go ahead and turn it down just in case it acts up before I can waste another half day of vacation to address this.

Any thoughts??



ernonemous

@wideopenwest.com
reply to peasoup42

That sounds like a flame sensor issue. Are you sure you're not interpreting the flame signal light with the power/error code light?
Error codes are generally constant until the unit is reset.


peasoup42

join:2012-12-26
Ridgecrest, CA
reply to peasoup42

Well, it looks like a pressure sensor switch is at fault according to Goodman (whether it was 3 or 4 blinkies) . Closest supplier is 3 states away, so both switches were ordered to avoid any confusion and having second switch causing the same problem. We'll have to see how it works out when they arrive.


robbin
Premium,MVM
join:2000-09-21
Leander, TX
kudos:1
reply to peasoup42

Now that we have an idea what the problem is, I "fixed" your original chronology of events.

said by peasoup42:

1. Inducer motor turns on (approx 30 secs)
2. Gas turns on ( ), igniters ignite ( ), pretty blue flame is produced for approx 5 secs ( ).
3. Gas shuts off ( ), blower motor turns on and runs ( ),Gas shuts off ( ) inducer motor shuts off ( ).
4. Blower motor continues to run ( ), while steps 1 thru 3 repeat ( ).

Had a Lennox that did this, but I believe that we had to replace the entire inducer motor assembly. What is happening is that when the blower comes on, it pressurizes the system and that is causing a fault in one of the pressure sensors. In other words, the pressure is correct with the inducer motor but not when the blower starts.


Lurch77
Premium
join:2001-11-22
Oconto, WI
kudos:4
reply to peasoup42

said by peasoup42:

Well, it looks like a pressure sensor switch is at fault according to Goodman.....

Have you checked for any blockages in the venting? Snow or ice, bird or bug nests, etc. A switch fault code just says that the switch is not doing what it is supposed to do during the sequence. That can mean a faulty switch, or it can mean the switch is doing what it is supposed to do when there is an air flow issue.

peasoup42

join:2012-12-26
Ridgecrest, CA

All venting, vacuum, and drainage lines were checked and are clear. They believe that the cold snaps we've had are to blame for the vacuum switch(s) being affected since they are so sensitive.



Lurch77
Premium
join:2001-11-22
Oconto, WI
kudos:4

1 edit

If cold weather hinders pressure switches, they certainly don't belong on a furnace. It's pretty rare I find an actual bad switch. Usually it's a motor problem or blocked vent. But I am glad to see you and they have covered all basis before replacing parts.


robbin
Premium,MVM
join:2000-09-21
Leander, TX
kudos:1
reply to peasoup42

Noticing that you had other problems prior to this event, I would also look very closely at the heat exchanger. A hole in the heat exchanger would create this fault.


peasoup42

join:2012-12-26
Ridgecrest, CA
reply to robbin

said by robbin:

Now that we have an idea what the problem is, I "fixed" your original chronology of events.

said by peasoup42:

1. Inducer motor turns on (approx 30 secs)
2. Gas turns on ( ), igniters ignite ( ), pretty blue flame is produced for approx 5 secs ( ).
3. Gas shuts off ( ), blower motor turns on and runs ( ),Gas shuts off ( ) inducer motor shuts off ( ).
4. Blower motor continues to run ( ), while steps 1 thru 3 repeat ( ).

Actually, the sequence I had was what it was doing. I had let it go a couple of cycles to make sure what was happening. But TY for double-checking me.

peasoup42

join:2012-12-26
Ridgecrest, CA
reply to peasoup42

Got home last night and noticed that the original sequence of events were happening AGAIN. So I decided to check the vacuum lines to the switches again. I didn't like the 'just enough' length of them, so I went up to the local auto parts store and got a few more inches of tubing. The new tube has no stress and possibly a better connection at the switches.

This morning the air in the ducts seemed chilly, but then again it was 22F out and it had just turned on about 10mins prior to give me a little heat. I went to the thermostat and shut the system off for about a min, turned it back on and definitely warm air was coming out.

I'm thinking the system just doesn't like running thru a 'normal' cycle without erroring out, but runs like a champ after a reset. Sure hope the new parts come soon and I don't have to do this ritual every morning...