Carrier Weather Maker error code 31 (or is it???)
#1
10-21-14, 07:05 AM
Carrier Weather Maker error code 31 (or is it???)
I've been scratching my head on this one for several days now.
Last year I got an error code 31. I did the typical trouble shooting, checked the pipes outside the house, cleaned out the drain traps and all hoses. The code was still there until I replaced the pressure switch. This kept the furnace working properly until last week.
So, same error code 31. The inducer motor starts up when there is a call for heat, but the igniter does not light up. To remedy this I can remove the coupling to the exhaust pipe and the furnace lights right up. I replace the coupling and the furnace runs and brings the house up to temp just fine. Typically it works ok for several hours then stops again with error code 31.
Recap. Igniter won't light unless the exhaust pipe is removed from the inducer motor.
Logically this makes me think the exhaust pipe is clogged.
Step 1:
So I rigged up some shop air and put 80 psi into the exhaust pipe to see if I could get something to blow out. At the exhaust pipe exit I capped the opening and drilled a 1/2 inch hole to create an orifice.
The result was lots, and lots of water stuck in the exhaust pipe.
Step 2:
Plumber snake found nothing in the exhaust pipe.
Any ideas what else could be going on?
Some things I haven't tried yet.
1. Checking pressure switch for water.
2. Replacing igniter.
Any help is appreciated.
Last year I got an error code 31. I did the typical trouble shooting, checked the pipes outside the house, cleaned out the drain traps and all hoses. The code was still there until I replaced the pressure switch. This kept the furnace working properly until last week.
So, same error code 31. The inducer motor starts up when there is a call for heat, but the igniter does not light up. To remedy this I can remove the coupling to the exhaust pipe and the furnace lights right up. I replace the coupling and the furnace runs and brings the house up to temp just fine. Typically it works ok for several hours then stops again with error code 31.
Recap. Igniter won't light unless the exhaust pipe is removed from the inducer motor.
Logically this makes me think the exhaust pipe is clogged.
Step 1:
So I rigged up some shop air and put 80 psi into the exhaust pipe to see if I could get something to blow out. At the exhaust pipe exit I capped the opening and drilled a 1/2 inch hole to create an orifice.
The result was lots, and lots of water stuck in the exhaust pipe.
Step 2:
Plumber snake found nothing in the exhaust pipe.
Any ideas what else could be going on?
Some things I haven't tried yet.
1. Checking pressure switch for water.
2. Replacing igniter.
Any help is appreciated.
#2
10-21-14, 07:15 AM
Member
At the exhaust pipe exit I capped the opening and drilled a 1/2 inch hole to create an orifice.
Your symptoms indicate the pressure switch is not closing. I suggest you remove the pressure switch hose where it attaches to the port on the inducer. If this port gets clogged or restricted by crud it prevents the pressure switch from closing. You can use a small drill bit or unopened paper clip to clean out the port. Make sure the port is clear all the way through.
#3
10-21-14, 07:53 AM
Sorry, let me re-explain the purpose of the cap I put on the exhaust pipe on the outside of the house.
The cap with the 1/2" orifice was used to "pressurize" the exhaust pipe in an attempt to dis-lodge any obstruction/debris that may be stuck in the pipe. When I was finished blowing air thru the pipe, the cap was removed prior to re-starting the furnace. So there are no modifications to my furnace.
I also removed the larger diameter hose (Down facing) that ran from the inducer to a black box and cleaned the hose with air and water, cleaned both ports as well.
Additionally I pulled the small hose running from the black box to the pressure switch and cleaned the hose as well as both ports.
The cap with the 1/2" orifice was used to "pressurize" the exhaust pipe in an attempt to dis-lodge any obstruction/debris that may be stuck in the pipe. When I was finished blowing air thru the pipe, the cap was removed prior to re-starting the furnace. So there are no modifications to my furnace.
I also removed the larger diameter hose (Down facing) that ran from the inducer to a black box and cleaned the hose with air and water, cleaned both ports as well.
Additionally I pulled the small hose running from the black box to the pressure switch and cleaned the hose as well as both ports.
#4
10-21-14, 08:07 AM
Member
Ok, I understand. The Carrier Weathermaker is a trade name and has numerous types and models in that line. To better assist, please post the model number of your furnace.
#5
10-21-14, 08:19 AM
58sxc100-jg
58SXC100-JG
It's a high efficiency furnace which is supposed to condense water, but the amount I'm finding in the exhaust pipe seems excessive.
So I've blown air thru the exhaust pipe, as well as ran a plumbing snake thru it.
The sequence is as follows.
Low back pressure (i.e. exhaust detached from inducer). The igniter glows, pressure switch clicks, gas comes on and is ignited by the glowing hot igniter. Viola there is heat.
High back pressure (i.e. exhaust attached to inducer). The igniter doesn't glow, pressure switch doesn't click, heat no come on, wife says call a professional, I start grumbling...
It's a high efficiency furnace which is supposed to condense water, but the amount I'm finding in the exhaust pipe seems excessive.
So I've blown air thru the exhaust pipe, as well as ran a plumbing snake thru it.
The sequence is as follows.
Low back pressure (i.e. exhaust detached from inducer). The igniter glows, pressure switch clicks, gas comes on and is ignited by the glowing hot igniter. Viola there is heat.
High back pressure (i.e. exhaust attached to inducer). The igniter doesn't glow, pressure switch doesn't click, heat no come on, wife says call a professional, I start grumbling...
#6
10-21-14, 08:33 AM
Member
Thanks for the model number. Does the vent pipe slope back toward the furnace and pitched 1/4" per foot? Also, make sure there are no sags in the pipe as a sag will cause condensate water to pool and restrict the air flow.
#7
10-21-14, 08:44 AM
That's the tough part.
I can only see the pipes at termination (outside) and at the furnace. The rest of the pipes are covered by the finished ceiling in my basement.
I'm assuming the builder followed the code and the inspector checked the installation, so the pipe slope should be correct.
I can only see the pipes at termination (outside) and at the furnace. The rest of the pipes are covered by the finished ceiling in my basement.
I'm assuming the builder followed the code and the inspector checked the installation, so the pipe slope should be correct.
#8
10-21-14, 08:59 AM
Member
Another issue that can cause the issue you are having is an issue with the secondary heat exchanger. Your furnace model number has had a history of bad heat exchangers. Here is a link that may be useful to you: http://dealer-meeting.behler-young.c...mb09-23_2_.pdf
#9
10-21-14, 10:16 AM
Well I hope it's not the HX's. We had both HX's replaced with new one's covered under this warranty about 3 years ago. The sign that the HX's were bad was a pool of water around the base of the furnace, as he inspected them it was obvious they were bad.
So everything from the HX's up is only 3 years old, and there is no visible sign of pooling water on the floor.
Good catch though, as some people are not aware of the faulty HX's and the lifetime warranty Carrier provides for them.
I ran home over lunch and tried to peek through the floor joists, but I can't fit my head in there. The unit was off again, so I got it back up and running so the family has heat while I'm at work.
I'll have to pick up a telescoping mirror after work and look for sagging pipes.
So everything from the HX's up is only 3 years old, and there is no visible sign of pooling water on the floor.
Good catch though, as some people are not aware of the faulty HX's and the lifetime warranty Carrier provides for them.
I ran home over lunch and tried to peek through the floor joists, but I can't fit my head in there. The unit was off again, so I got it back up and running so the family has heat while I'm at work.
I'll have to pick up a telescoping mirror after work and look for sagging pipes.
#10
10-21-14, 10:48 AM
Member
I.m trying to cover all the things that normally cause the issue you are having. That is great you had the heat echangers replaced under warranty. One more thing I failed to ask: do you have a pipe bringing in combustion air from the outside? If so, have you checked to make sure there is nothing blocking or restricting air flow?
In case you don't have it here is a link that may be useful:
http://dms.hvacpartners.com/docs/100.../58SXC-3SI.pdf
In case you don't have it here is a link that may be useful:
http://dms.hvacpartners.com/docs/100.../58SXC-3SI.pdf
#11
10-21-14, 10:59 AM
Yes I have a pipe that supplies fresh air to the furnace. It is turned downward similar to Fig. 13 in the document you referenced, and is located within 12 inches of the exhaust pipe. The pipes are then covered by a box made of baulsters to keep animals and debris out of them.
The intake pipe did have suction when the furnace was running, but it felt weak compared to the exhaust side. Just as a preventative countermeasure I snaked both intake & exhaust from the outside going in.
There are alot of leaves in this area that I routinely sweep up to prevent collecting around the box that protects the pipes. I've been so focused on the exhaust pipe, I'll go back and double check the intake just to make sure.
The intake pipe did have suction when the furnace was running, but it felt weak compared to the exhaust side. Just as a preventative countermeasure I snaked both intake & exhaust from the outside going in.
There are alot of leaves in this area that I routinely sweep up to prevent collecting around the box that protects the pipes. I've been so focused on the exhaust pipe, I'll go back and double check the intake just to make sure.
#12
10-21-14, 11:16 AM
Member
Yes, that intake pipe being unrestricted is critical for proper operation. It doesn't take much to prevent the pressure switch from closing. If you get a chance you might want to check where the vent pipe connects to the inducer motor. If you snaked from the outside in you could have inadvertently pushed something into the inducer or stuck something in the outlet. I have found dead birds and other debris in the inducer motor which prevented enough vacuum to close the pressure switch and allow the ignition sequence to continue.
#13
10-21-14, 11:50 AM
Hmmm... The intake pipe comes into the top of the furnace directly to the combustion chamber. The inducer motor sits down below and there is no clear intake pipe to inducer motor connection.
My thought is the way my system is set up:
1. Intake air comes from outside straight to the combustion chamber.
2. Inducer starts cycle and pulls fresh air thru the combustion chamber and shoots it out the exhaust.
3. If the system pressure is within spec, the Igniter glows. <- First problem!
4. If the system pressure is within spec, the pressure switch is activated and supplies gas. <- Second problem!
Since my igniter only glows when the exhaust pipe is removed, could it be an intake pipe blockage?
My thought is the way my system is set up:
1. Intake air comes from outside straight to the combustion chamber.
2. Inducer starts cycle and pulls fresh air thru the combustion chamber and shoots it out the exhaust.
3. If the system pressure is within spec, the Igniter glows. <- First problem!
4. If the system pressure is within spec, the pressure switch is activated and supplies gas. <- Second problem!
Since my igniter only glows when the exhaust pipe is removed, could it be an intake pipe blockage?
#14
10-21-14, 11:54 AM
Member
Since my igniter only glows when the exhaust pipe is removed, could it be an intake pipe blockage?
#15
10-22-14, 09:24 AM
You were correct. I found some leaves blocking roughly 50% of the inlet screen. I would attach a picture, but this website has a finicky picture uploader and I gave up after 4 attempts.
The furnace is up and running smoothly. Thanks again for your help!
The furnace is up and running smoothly. Thanks again for your help!
#17
12-26-14, 07:56 AM
I suggest you remove the pressure switch hose where it attaches to the port on the inducer. If this port gets clogged or restricted by crud it prevents the pressure switch from closing. You can use a small drill bit or unopened paper clip to clean out the port. Make sure the port is clear all the way through.
Thanks!
