Carrier Natural Gas Furnace not completing cycle

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  #1  
Old 11-21-08, 12:08 AM
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Question Carrier Natural Gas Furnace not completing cycle


I am a novice and will try to explain what is going on and see if anyone can help me out. I just bought this house and it has a 1995 Carrier Gas Furnace that wonít complete a cycle and it seems like a fan is running almost all the time. Here is the sequence that I have found happens. This happens when I have the thermostat set or when I crank it up to say 80 degrees.

~A fan will kick on and run for a few minutes
~I hear a click and then the flame lights
~The flame may stay lit for a few minutes (1-3)
~Then a fan starts running
~Everything stops for a short time period and then it starts over again.

I had a service tech come out and he cleaned the burners and said that the furnace was JUNK and I needed to replace it. I know it is somewhat old (13 years) but I thought I could get a few more years out of it. The house was really dirty when I moved in and I suspect that the evaporator coil is full of dirt, however, I just suspect this and donít know that for sure or if that causes anything. However, I have checked the temperature above the evaporator coil and when it gets to around 145F the flame shuts off. I thought it may be getting to hot and that was shutting it down, but the sticker on the furnace says that this shouldnít happen until it reaches 170F.

Does anyone have any suggestions?
 
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  #2  
Old 11-21-08, 03:01 AM
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Since posting my original post I have thought of a few things that may be helpful. I live in Kansas City, MO so the temperatures differ frequently. Yesterday it was 65 today its 34. I live in a two story split level home. The furnace is in the basement (finished) and I will have to get the model. The thermostat is whatever came with the unit I assume because it is also carrier. Also, after reading here I have additional questions. I also have a heat pump. I donít understand why my furnace is trying to kick on when it isnít less than 32 degrees outside. Could the fans that I here running a lot be due to the heat pump.

Also, even though the HVAC man told me my furnace was junk my home is staying warm (~68). I donít understand how it is heating up since the flame wonít stay lit longer than a few minutes. Could it be that the heat pump is what is creating my heat?
Iím confused, sorry if this doesnít make sense and thanks in advance to anyone who can assist.

Also, I looked at the furnace yesterday and I think it said it was 88 BTU
 
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Old 11-22-08, 01:16 AM
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Ok, I have more info.
My furnace is a Carrier model 58PAV090-14 with serial # 1295A16944 and the heat pump is HA1CJ030A. The HVAC guy told me that the 5MFD blower motor capacitor was reading 3.1 so I changed that yesterday myself. He said that the high limit didn't had no continuity so I changed the t-stat. However, it wasn't as long as the one I took out. Could this be a problem? He also said the dual run capacitor was reading low, but I dont know what that is.

I changed those two parts and the flame stayed lit a little longer than normal ( it stayed lit for about 7-8 minutes instead of 3-4). The furnace has an input of 88 BTU and output of 70 something BTU. It is stil cutting off though and I don't know what the problem could be. Any suggestions?
 
  #4  
Old 11-22-08, 01:26 AM
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One other thing I forgot is that the LED light blinks three times kinda fast them stops for a second and blinks three more times. I don't know how to look up this code, but someone told me it was a dirty filter code. I don't know if that is true or not but I have changed my filter.
 
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Old 12-01-08, 10:33 PM
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Originally Posted by fleming6998 View Post
I had a service tech come out and he cleaned the burners and said that the furnace was JUNK and I needed to replace it.
Looks like I would not be calling this guy/company back if he said that.


The house was really dirty when I moved in and I suspect that the evaporator coil is full of dirt, however, I just suspect this and donít know that for sure or if that causes anything. However, I have checked the temperature above the evaporator coil and when it gets to around 145F the flame shuts off.
I think you are getting somewhere... Anyway you can try to get a reading below the coil?

Originally Posted by fleming6998 View Post
One other thing I forgot is that the LED light blinks three times kinda fast them stops for a second and blinks three more times.
It means the high limit has tripped. A dirty coil will cause this.

I also have a heat pump. I donít understand why my furnace is trying to kick on when it isnít less than 32 degrees outside.
Depends on what the temp is set at the stat, and room's temp.

I see you said you put in a new t-stat, what did you put in? (make and model)
 
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Old 12-02-08, 10:44 PM
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Thanks a lot Jay for your comments and input! I agree with you that the service tech shouldn't have said that. I will get a temp below the coil and report back tomorrow. I did say I put in a new t-stat, but I miss spoke. I replaced the high limit that didn't have any volts running through it. I called it a t-stat but actually it was the high limit switch. It was about an inch shorter than the one I took out. I hope this isn't a problem too. Since my last post I adjusted the heat anticaptor. It was set on .6 and I tested the amps on the white and red wire in the t-stat and I got a reading of .4x. So, I adjusted the heat anticaptor to 0.4 and it isn't kicking on and off as much, but the flame still isn't staying lit long. I plan on cleaning the coil this weekend. In the mean time I will get a temp below the coil and see if this may help determine if the coil is for sure dirty. Thanks again for your input I really do appreciate it.
 
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Old 12-03-08, 04:37 PM
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You need to volt test to see what is REALLY kicking out. Is the limit cutting out?, or could the stat be cutting out? You can separately test to know which.

And, the higher the anticipator setting, the LONGER the cycles become. Some mechanical stats even have the word "longer --->" written across the metal of the anticipator, with arrow pointing in direction of the .4, .6, .8. 1.0, 1.2.
 
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Old 12-04-08, 03:32 AM
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Thanks ecman

Thanks ecman for your input. My batteries died on my themometer so I will have the temp reading later tonight.

Maybe I changed the heat anticpator the wrong way then. I just tested the amps and it was .4 so I moved it to that. Maybe I should have increased it.

I have been wary of testing the volts because I thought I might short the circut, but I seen on another post were you described how to do it. I will test the limits and switches today and see if I can figure out what is kicking off.

Since the high limit was bad and I replaced it with a shorter one could that be my problem? I also think my blower fan is really dirty and I am going to attempt to clean it today as well.

Thanks again to you all for helping me. It is 24 outside right now so I hope I can get this thing working like it is supposed to before it dies on me.
 
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Old 12-04-08, 08:34 AM
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update

Ok, here is what I have found today. I measured the temp and it was 68-70 were the filter is. Above the A coil it rose to 135-138 when it shut off. One time it shut off at 135 and the next time I measured it the flame shut off at 138. I did notice that the flue was very hot to the touch. This didn't seem right. I plan on taking the blower motor out and cleaning the fan blade because it was really dirty IMO.

As far as testing the switches I was getting 28 volts on everything when everything it started up. I tested the volts on the high limit (this is above the flame and is inside of the firewall of the furnace and has two red wires) the left side of the limit didn't loose any volts, but when the flame shut off the right side went from 28 volts to zero. Could this be due to me replacing the old one with a shorter one? Also, below this is the flame roll out switch and it also didn't have any volts. I didn't volt test this while the flame was lit.

I then turned the power off and turned the heat on the t-stat on and tested the orange wire on the pressure switch (this is located up top by the inducer motor) that comes from the circuit board. It had 24 or 28 volts I can't remember and when the flame went off the volts went to zero. I restarted the system and tested the volts on the yellow wire that came off of the LGPS (low gas pressure switch) and it did the same thing.

I was hoping that some of this information would be helpful, but to me it seems like it just complicates things even more. Again I thank each of you that have helped me along the way and have gotten me this far. I have learned a lot and appreciate your feedback as I look forward to it.
 
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Old 12-04-08, 09:43 AM
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Are all the supply and return vents open and unobstructed?
 
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Old 12-04-08, 01:46 PM
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Originally Posted by fleming6998 View Post
Ok, here is what I have found today. I measured the temp and it was 68-70 were the filter is. Above the A coil it rose to 135-138 when it shut off.
ANy reading before the A-Coil?
 
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Old 12-04-08, 04:43 PM
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Originally Posted by fleming6998 View Post
As far as testing the switches I was getting 28 volts on everything when everything it started up. I tested the volts on the high limit (this is above the flame and is inside of the firewall of the furnace and has two red wires) the left side of the limit didn't loose any volts, but when the flame shut off the right side went from 28 volts to zero.
This proves it is indeed high limiting, at least according to the switch.

Could this be due to me replacing the old one with a shorter one?
I am no furnace engineer. I put things back in that look like the old part. It is hard to say. Heat currents may be different in different parts around the exchanger. I have noted when I have opened up an A-coil plenum, that hot heat is prevelant in one spot of the plenum and cool in another, as it all updrafts!



Also, below this is the flame roll out switch and it also didn't have any volts. I didn't volt test this while the flame was lit.
Well, do the test. But I think you will find that the limit switch 'took out' the curent supplying the roll out switches, as all these things are in series. When one goes out, it takes out what is downstream. The reason only ONE side of the limit switch went out, instead of both sides, is that the limit is the culprit.
 
  #13  
Old 12-04-08, 11:34 PM
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Originally Posted by Jay11J View Post
ANy reading before the A-Coil?
I am not sure how to gain acess before the A-Coil, so no I didn't get a temp reading below the coil. I do have a register that is by the wall, which is above the A coil and I put my hand in there when the flame is lit and I can feel hot air.

badtlc : Are all the supply and return vents open and unobstructed?

Yes all are open and unobstructed. Actually I have taken out all of the vents to clean them

Ecman:
I agree that I should have replaced it with the same part. I took the high limit to the heating/cooling parts store and the one I purchased is the one the guy told me was the replacement part. I told him it was shorter and he said it wouldn't be a problem because the high limit was 170 and that is what his parts high limit was. That sucks that the high limit I bought is the culprit. Do you think I should replace it again? Maybe go to a different part store and get one that is the same size.

Also, I tested the roll out switch and it gave me the same results, which make sense. The high limit right side goes out so it cannot carry any current to the flame roll out switch so it will not have any volts.

I guess I will try to find another part store and keep you all posted. Thanks again for all of the input and help!
 
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Old 12-05-08, 06:38 AM
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Without rereading this entire thread - there must have been some reason you replaced the limit switch. Likely because your problem is the same as what it is now?

If that be the case, then good chance the original same length limit switch will not fix your problem. Also, if you had said your original one was short, but the new one was long, THEN, I'd be more prone to think that the replacement limit switch could be an issue, say by getting the end too close to a heat exchanger, perhaps. But since it is the other way around, it probably is doubtful that is causing the issue. But I'm not 100% either.

Are you familiar with those 6 inch long (inexpensive) probe thermometers that have like the 1 inch temp dial on the end, that you can buy in grocery stores and places like Harbor Freight? If you get one of these, you could drill about a 1/8 inch hole in the plenum, per Jay's, location and stick it in there and see what you get.

Could there be a chance your blower motor is not spinning as fast as it used to or the cupped vanes are full of dust? Do you have a higher AC blower speed you can swap out from the control board, by transfering each wire, at least to see if that stops the high limit?
 
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Old 12-05-08, 06:46 AM
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Are you able to post a photo of your system lay out? then I can see if you can find a way into the bottom side of the coil.
 
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Old 12-05-08, 02:40 PM
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Originally Posted by ecman51` View Post

Are you familiar with those 6 inch long (inexpensive) probe thermometers that have like the 1 inch temp dial on the end, that you can buy in grocery stores and places like Harbor Freight? If you get one of these, you could drill about a 1/8 inch hole in the plenum, per Jay's, location and stick it in there and see what you get.

Could there be a chance your blower motor is not spinning as fast as it used to or the cupped vanes are full of dust? Do you have a higher AC blower speed you can swap out from the control board, by transfering each wire, at least to see if that stops the high limit?
Yes, I have one of the probe thermometers. I think your second paragraph is on the money. The fan blades on the motor are nasty. Tomorrow I have a guy from work coming over and we are going to take the blower motor out and clean it. Also we are going to cut a hole in the sheet metal that is covering up access to the A coil and clean it. I currently have the blower motor for heat set on medium speed. It has low, medium low, medium, and a/c speeds. I am not sure if it is spinning fast as it used to. I just purchased this house and the previous owners were nasty to say the least. Thanks for your continued input! I will let you know what I find.

Originally Posted by Jay11J View Post
Are you able to post a photo of your system lay out? then I can see if you can find a way into the bottom side of the coil.
Yes, I have pictures but can't find the cord that hooks up from my camera to my PC. When my wife comes home I am sure she has hidden it from me, LOL. I will upload them tonight or in the morning. Thanks a lot for your help, too.

With all of your help we will get to the bottom of this soon. I can't express enough how much I thank each of you for taking the time out of your day to help me.
 
  #17  
Old 12-06-08, 06:55 AM
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Here are a 4 pictures of the furnace (with cover, flame lit/non lit and so forth) I hope I can upload them.

<a href="http://s202.photobucket.com/albums/aa224/sflemi00/?action=view&current=DSCI0324.jpg" target="_blank"><img src="http://i202.photobucket.com/albums/aa224/sflemi00/DSCI0324.jpg" border="0" alt="Photobucket"></a>

<a href="http://s202.photobucket.com/albums/aa224/sflemi00/?action=view&current=DSCI0327.jpg" target="_blank"><img src="http://i202.photobucket.com/albums/aa224/sflemi00/DSCI0327.jpg" border="0" alt="Photobucket"></a>

<a href="http://s202.photobucket.com/albums/aa224/sflemi00/?action=view&current=DSCI0328.jpg" target="_blank"><img src="http://i202.photobucket.com/albums/aa224/sflemi00/DSCI0328.jpg" border="0" alt="Photobucket"></a>

<a href="http://s202.photobucket.com/albums/aa224/sflemi00/?action=view&current=furnace.jpg" target="_blank"><img src="http://i202.photobucket.com/albums/aa224/sflemi00/furnace.jpg" border="0" alt="Photobucket"></a>

Does this help?
 
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Old 12-06-08, 06:58 AM
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sorry the pics are so big I thought I had reduced the size, but apparently I did not. The rust on the burnes is from what I can tell the condenser froze up over the summer and leaked on to the burners. I know this could be a problem in the future, but for now it appears that it is just surface rust.
 
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Old 12-06-08, 04:17 PM
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You got a cased coil, should be a few screws that hold the cover in place.. When you remove the cover, you can see the coil.
 
  #20  
Old 12-07-08, 10:23 PM
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Hey thanks guys again for your help.

I will add pics later tomorrow to show you what the A coil looked like before and after. Wow, was it dirty. We cleaned about 1/8 of an inch of dirt/grim off of the a coil. We also took out the blower motor and cleaned it as well as the fins. However, the blower motor is making a whinning noise sometimes and I think I need to take it out and clean it a little better or readjust it.

I don't get the 33 fault code anymore. Which is good and the burners stay on longer although I haven't timed it yet. I placed this instrument up to one of the ducts that measures wind and it measured Low before we cleaned the coil and after we cleaned it, it measured 12. I am not sure what the measurment units are.

However, I have noticed that sometimes like yesterday when it was 52 outside that the blower will kick on, but the flame doesn't lite. Is this normal? The air coming out of the vents is luke warm. Could this be the heat pump making the heat? I know I am low on R-22, could this also be the problem? I am kind of confused. I thought the heat pump heated the house when the temp wasn't so cold outside. Correct me if I am wrong.

Again, thanks everyone for helping figure out how to stop that error 33 code.
 
  #21  
Old 12-09-08, 12:04 AM
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As I said the other day thanks for all of your input guys!
Here are some pics of what the A coil looked like before and after. This may help someone in the future.

Before
<a href="http://s202.photobucket.com/albums/aa224/sflemi00/?action=view&current=DSCI0331.jpg" target="_blank"><img src="http://i202.photobucket.com/albums/aa224/sflemi00/DSCI0331.jpg" border="0" alt="Photobucket"></a>

<a href="http://s202.photobucket.com/albums/aa224/sflemi00/?action=view&current=DSCI0332.jpg" target="_blank"><img src="http://i202.photobucket.com/albums/aa224/sflemi00/DSCI0332.jpg" border="0" alt="Photobucket"></a>

After
<a href="http://s202.photobucket.com/albums/aa224/sflemi00/?action=view&current=DSCI0333.jpg" target="_blank"><img src="http://i202.photobucket.com/albums/aa224/sflemi00/DSCI0333.jpg" border="0" alt="Photobucket"></a>

<a href="http://s202.photobucket.com/albums/aa224/sflemi00/?action=view&current=DSCI0334.jpg" target="_blank"><img src="http://i202.photobucket.com/albums/aa224/sflemi00/DSCI0334.jpg" border="0" alt="Photobucket"></a>
 
  #22  
Old 12-09-08, 07:00 AM
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Oh yeah, that would of been your problem.

Glad to see you were able to get in there and clean it out.

Not many older furnace has that type of case to get into the coil that easy.
 
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