Furnace blows semi warm air for 3 minutes, gets lukewarm, shuts off

[danski0224]

Checked the duct the leads to the room not getting a strong current of air, everything seems to be fine but I have no way of checking inside without ripping it open to see if its clogged...

That's the difference between a pro that can do airflow diagnostics and someone that can't. Still can't see inside, but some measurements can point in the right direction.

Hard to guess though. You can always keep throwing parts at it

 

[DropShotter]

That's the difference between a pro that can do airflow diagnostics and someone that can't. Still can't see inside, but some measurements can point in the right direction.

Hard to guess though. You can always keep throwing parts at it

its amazing how many service calls are made when all the problem is is something as simple as a dirty flame sensor or debris in an igniter. I like ruling out every possible thing I can physically do before throwing my money at an overpaid technician.


there is a white pipe in front of the furnace (1 inch or so, PVC). It leads to the top and to the bottom of the furnace. In the middle there is a joint. The joint has three openings. The two on the sides lead to both pipes but in the middle its exposed. not capped, completely open. Is that supposed to be like that?

 

[danski0224]

its amazing how many service calls are made when all the problem is is something as simple as a dirty flame sensor or debris in an igniter. I like ruling out every possible thing I can physically do before throwing my money at an overpaid technician.

Sometimes, the bill is for experience and knowledge.

I'm sure the argument can be made that you are overpaid too.

 

[DropShotter]

Sometimes, the bill is for experience and knowledge.

I'm sure the argument can be made that you are overpaid too.

well i cant argue with that

 

[acmikee]

remove the bottom panel and access the circuit board. cut and wire nut the door safety switch together. close the panal and cycle the unit. let it trip off now open the panel and count the # of flashing lites on the circuit board it will give your fault codes. you should be able to find the codes on the panel or online. if no codes jumper the R&W wire to bring on the heat. if it doesnt trip off its your tstat

 

[philjafo]

remove the bottom panel and access the circuit board. cut and wire nut the door safety switch together. close the panal and cycle the unit. let it trip off now open the panel and count the # of flashing lites on the circuit board it will give your fault codes. you should be able to find the codes on the panel or online. if no codes jumper the R&W wire to bring on the heat. if it doesnt trip off its your tstat

I've said before in this thread never bypass a safety switch, besides if you have an airflow issue running with that door open will hide the issue by allowing extra air in. If you truly did just have an HVAC company out there to clean your ducts and service the furnace you should call them back and give them a chance to stand behind their work.

 

[acmikee]

if you have an airflow issue running with that door open will hide the issue by allowing extra air in. thats why i said to close the panel. you need to be able to read the codes and cycling the power resets them.

 

[DropShotter]

I just did a test to see if its the thermostat. Followed these instructions (wrapping the white and red wires together):

http://homeguides.sfgate.com/tell-home-thermostat-bad-42323.html

my furnace is blowing hot the longest it ever has, hasnt shut off, and is raising the house about ten degrees now.

is it safe to say that I need a new thermostat and that was the problem all along?

EDIT: jk, false alarm. Unit shut off and is doing its thing again. I sat up there and watched and listened to its complete cycle. In the middle of the furnace (middle pannel) the unit sounds like water boiling or swishing around in it. What is that? I noticed it does that at the beginning of the cycle and then it does it right before the burners cut out

EDIT2: I cant find a reset limit switch anywhere online that matches mine. My model is a PRODUCT: 58SXC040---101GG
MODEL: 58SXC040-GG

When I search for a reset limit the only thing I can find is this:
http://www.ebay.com/itm/Carrier-Bry...020&pid=100052&prg=1023&rk=1&sd=281044387869&

but the closest model number to mine is 58SXC040100GG

and it looks nothing like my switch. Mine is round and black:
http://img717.imageshack.us/img717/4822/67903637.jpg

 

[55bigblockcid]

It sounds like it is full of condensate
I read through this post again and could`nt see where you posted a model number.
That would be helpful.Also brand.
It`s usually located inside on the frame.
If it`s a condensing furnace it may not be draining properly not allowing the pressure switch to close or stay closed.
Or it runs until the condensate level reaches the pressure switch tubing port and then opens the switch.
Also can you post some pictures of the whole unit with the covers off?
Also your drain line so we can get some better perspective of what ya have there?

 

[55bigblockcid]

You`re top picture is a manual reset hi limit switch.The bottom picture is a flame roll out switch.

I found this manual per the model number given.I think your heat exchanger may be plugged with soot.Iv`e seen one like yours do the same thing.There may be a recall on your heat exchanger.Some were coated on the inside and started to flake off the coating and plugging up the heat exchanger.My service manager had one and he was able to get the heat exchanger for free through Carrier but they wouldn`t cover labor for the change out.This is what they suggest first.http://www.docs.hvacpartners.com/idc/groups/public/documents/techlit/58d,s-6sm.pdf Step #3
It is very hard to read.Maybe you can get a copy of that emailed to you from carrier I don`t know. [ 99% sure ]

 

[DropShotter]

It sounds like it is full of condensate
I read through this post again and could`nt see where you posted a model number.
That would be helpful.Also brand.
It`s usually located inside on the frame.
If it`s a condensing furnace it may not be draining properly not allowing the pressure switch to close or stay closed.
Or it runs until the condensate level reaches the pressure switch tubing port and then opens the switch.
Also can you post some pictures of the whole unit with the covers off?
Also your drain line so we can get some better perspective of what ya have there?

carrier
PRODUCT: 58SXC040---101GG
MODEL: 58SXC040-GG

Ill get some pics in a second. And where abouts would my drain line be? Is that the pipe thats near the AC unit outside that usually has water coming out of it?

 

[DropShotter]

http://img809.imageshack.us/img809/9684/20130213123343.jpg
http://img267.imageshack.us/img267/8158/20130221193445.jpg
http://img189.imageshack.us/img189/4987/20130221193528.jpg
http://img842.imageshack.us/img842/3098/20130221193542.jpg
http://img39.imageshack.us/img39/5442/20130221193556.jpg

im seeing a few drops here and there come out
http://img826.imageshack.us/img826/9456/20130221193848.jpg

You`re top picture is a manual reset hi limit switch.The bottom picture is a flame roll out switch.

the bottom picture is what is on the exact opposite side of the top picture. That shiny chrome smooth surface on the inside of the box is attached to the round black box that is on the outside of the box. Im wondering if I were to replace my limit switch (like people suggested), what exactly would be replaced and why cant I find the part for it anywhere online?

 

[55bigblockcid]

I stand corrected on the roll out switch.I thought you were posting two seperate ones.They call that an auxiliary limit switch.overtemp-manual reset,spst-[n.c.] Its als on this wiring diagram.page 12.

http://www.docs.hvacpartners.com/idc/groups/public/documents/techlit/58sxc-1si.pdf

 

[DropShotter]

I stand corrected on the roll out switch.I thought you were posting two seperate ones.They call that an auxiliary limit switch.overtemp-manual reset,spst-[n.c.] Its als on this wiring diagram.page 12.

http://www.docs.hvacpartners.com/idc/groups/public/documents/techlit/58sxc-1si.pdf

any chance that that part went bad with the symptoms im having?

on page 3, it shows a filter. I have never checked or washed this filter. I wonder if that could be a problem as well


http://img39.imageshack.us/img39/5442/20130221193556.jpg
After looking at the picture, i cant seem to see the filter anywhere. And I remember when I was up there, looking in that area, I looked behind that circuit board and I could see directly into an air duct (big silver one) that went behind the furnace and then came out the side. Did not see a filter anywhere

EDIT: I noticed something else. after i reset everything, whether it be unplugging the furnace or taking the TSTAT off and touching the R & W wires together, the system will run for like 15 minutes, hot, and then shut off. The second time is less. third time is even lesser. Then the fourth of 5th time, the blower will kick in (after the furnace lights) for literally like 2 seconds and then it all shuts off and wont turn back on until I mess with either the TSTAT or unplug and re-plug it in.

 

[gpalmer77]

Check the tubing that drains water from the fan on the vent stack. High efficiency furnaces use a fan assisted stack, not natural draft flue gas. If the tubing is blocked, the fan casing fills up with water as it condenses in the flue and drains back. There is a pressure switch to kill the furnace if the fan isn't running, but it has the same effect if the fan is full of water.

 

[gpalmer77]

Take off the black hose with the green clip in your photos, just above the stack fan. I think this hose is plugged. When I had this problem, I also disassembled the fan itself to get all the water out.

 

[DropShotter]

Take off the black hose with the green clip in your photos, just above the stack fan. I think this hose is plugged. When I had this problem, I also disassembled the fan itself to get all the water out.

pardon the ignorance, but which picture is it? I couldnt point out a stack fan to save my life. And I see a few black hoses with green clips lol. Should I expect a ton of water to come out or clogged debris? if it is clogged, where has the condensation been pooling? Or is that why its shutting off, because it cant?

 

[danski0224]

It amazes me sometimes, the amount of work some go through to avoid calling someone.

 

[philjafo]

http://www.ismyfurnacesafe.com/exchanger.aspx

Check this link dropshotter, plugged drains and the symptoms you have point to the secondary heat exchanger delaminating, once that happen it rust through from the inside out. I see this a lot on carrier furnaces, I've even seen it on very new ones as in less then 2 years old. And this is also why I recommended calling someone, a hole in the heat exchanger is very serious.

 

[DropShotter]

It amazes me sometimes, the amount of work some go through to avoid calling someone.

and it amazes me how quick people are to call someone instead of trying to learn and fix something themselves. Just in doing everything I have done so far I have learned a ton about something i own. Just like how I taught myself to do a propper coolant flush in my car last month instead of taking it to a shop and having them overcharge to have it done when its really rather simple.

 

[55bigblockcid]

http://www.ismyfurnacesafe.com/exchanger.aspx

Check this link dropshotter, plugged drains and the symptoms you have point to the secondary heat exchanger delaminating, once that happen it rust through from the inside out. I see this a lot on carrier furnaces, I've even seen it on very new ones as in less then 2 years old. And this is also why I recommended calling someone, a hole in the heat exchanger is very serious.

^^^^^^^^^^^ BINGO^^^^^^^^^^^^^as I previously mentioned!

 

[5.0vert]

Take off the black hose with the green clip in your photos, just above the stack fan. I think this hose is plugged. When I had this problem, I also disassembled the fan itself to get all the water out.

I had this problem with my Carrier furnace after doing some drywall work. I had it all cleaned up by a HVAC company but they must of missed the condensate hose. Water was backing up into the fan and shutting down the sytem.

It took 3 different techs throwing parts at it to finally figure out it was a clogged hose.

 

[DropShotter]

I had this problem with my Carrier furnace after doing some drywall work. I had it all cleaned up by a HVAC company but they must of missed the condensate hose. Water was backing up into the fan and shutting down the sytem.

It took 3 different techs throwing parts at it to finally figure out it was a clogged hose.

exactly. And I have had several occasions of the exact thing happen with different devices I didnt know about or care to learn about and wasted a lot of money. I dont believe I am working beyond my limit but I am almost there. I think checking these hoses is going to be the last thing and if it doesnt work then I will call someone. I dont know why people are so persistent on immediately calling a technician out instead of just giving as many suggestions as possible.

so anyways, based on the photos I posted, which of the black hoses with green clips should I be checking?

 

[Andx0r]

Both of them, where they go into the cyndrilical black drain trap in front of your blower fan. If you do have a drainage problem, chances are you'll get a gush of water out of one of them. The hoses won't be clogged, but the black plastic drain trap they're attached to will be.

And being a 20-year-old Carrier SX (you should really just replace that, btw), chances are it'll be clogged with a combination of brown mold and black flakes. The black flakes are the secondary Hx coating delaminating and rinsing down into the drain trap.

I dont know why people are so persistent on immediately calling a technician out instead of just giving as many suggestions as possible.

Because, malfunctioning gas-fired HVAC equipment can create danger. Like burning your house down danger or poisoning your family with carbon monoxide danger.

And judging by every post you've made in this thread, your actual qualification to do anything beyond a filter change ranks somewhere just above that of a starfish, in spite of all the 'learning a ton about something you own' that you've done. The only reason I'm posting what hose you should look at is just in the hope that you'll quite monkeying with your furnace and call a professional already. It's not a dishwasher or television set you're messing with.

Sorry to sound harsh, but I have to deal with destroy-it-yourselfers on a daily basis and you are fitting the mold to a T here.

 

[DropShotter]

Both of them, where they go into the cyndrilical black drain trap in front of your blower fan. If you do have a drainage problem, chances are you'll get a gush of water out of one of them. The hoses won't be clogged, but the black plastic drain trap they're attached to will be.

And being a 20-year-old Carrier SX (you should really just replace that, btw), chances are it'll be clogged with a combination of brown mold and black flakes. The black flakes are the secondary Hx coating delaminating and rinsing down into the drain trap.



Because, malfunctioning gas-fired HVAC equipment can create danger. Like burning your house down danger or poisoning your family with carbon monoxide danger.

And judging by every post you've made in this thread, your actual qualification to do anything beyond a filter change ranks somewhere just above that of a starfish, in spite of all the 'learning a ton about something you own' that you've done. The only reason I'm posting what hose you should look at is just in the hope that you'll quite monkeying with your furnace and call a professional already. It's not a dishwasher or television set you're messing with.

Sorry to sound harsh, but I have to deal with destroy-it-yourselfers on a daily basis and you are fitting the mold to a T here.

the things I am checking are hardly "destroy it yourself". And the reason im not rushing to replace the whole unit is because when the guy came out last year and did a full service job on it, he said everything looked to be in good shape.


I get the feeling that 90% of the responses on here are from actual HVAC techs who hate the idea of people doing their own work because that takes business away from them. no?

 

[D.J.]

They just might be tring to save your familys life on this one! Make sure you have a carbon monoxide dectector installed and working in your residence so noone has to read about your family and you dieing in your house from a clogged heating system.

 

[DropShotter]

it was the hoses. Clogged up like whoa. cleaned it all out but its time for a new unit. Will be getting a new furnace soon. My house is only like 1,100 sq ft. How much do furnaces typically run?