Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > HVAC

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Reply
 
Thread Tools Search this Thread Display Modes
Old 11-29-2011, 08:20 AM   #1
Newbie
 
Join Date: Nov 2011
Posts: 7
Share |
Default

My furnace died


Hello,
My furnace died over the weekend. A furnace repairman came over and did things for about an hour- he got it running by turning the furnace off using the switch thats bolted to the ceiling, taking off the LOWER cover, to open the safety switch down there (that opens autmatically when you take the cover off); then pulling a wire off of what I think is called the "main limit switch", then he put the cover back on, closing the switch, flipped the main ceiling furnace switch back to on, and plugged the wire he had disconnected to the "main limit switch" back on.......presto I have heat........for 12 hours or so anyways, then it turned off again!! I dont want to spend another 120 dollars for a 12 hour fix.

I tried to do what he did, but can only get the blower motor going, no heat or flame.
Any suggestions? I have to admit the furnace hasnt been maintained, I though these things were rather foolproof. How do I clean the flame area, exchanger, etc etc? The drain pipe OUTSIDE of the furnace has a small crack in it from being unsupported, the wieght of the pipe itself made it crack, does this matter or not? its outside of the furnace, so I didnt worry about it when I saw it a while ago.
Please help. I am relatively handy but obviously am a noob when it comes to furnaces.......sincerely
BobPike.

BobPike is offline   Reply With Quote
Old 11-29-2011, 08:30 AM   #2
I'm Your Huckleberry
 
Join Date: Mar 2011
Posts: 5,620
Default

My furnace died


It would appear that you have another limit switch tripped. All he did was either reset one or bypass it unless he just so happened to have an extra new limit switch on his person or in his truck.

Usually you'll have a few limits. If he simply reset the one than it very well could be the same on has tripped once again.

Google search "Furnace High Temperature Limit Switch" as well as search for a Youtube vid of them.


One of these other guys will be along to assist you as well, I'm sure.

BTW, you have an air flow problem. These things don't just trip on their own. Your furnace is overheating, the switches are doing their job correctly by not allowing the furnace to ignite.

Have your evaporator coil checked and cleaned and keep that air filter in brand new condition, no exceptions. No more tripping of limit switches.


Last edited by Doc Holliday; 11-29-2011 at 08:33 AM.
Doc Holliday is offline   Reply With Quote
Old 11-29-2011, 08:32 PM   #3
An old Tradesmen
 
Join Date: Oct 2008
Location: PA
Posts: 24,778
Default

My furnace died


He never fixed your furnace. Call him/that company back up and let them know. They shouldn't charge you other then for the correct fix, that they didn't do.
beenthere is offline   Reply With Quote
The Following User Says Thank You to beenthere For This Useful Post:
ben's plumbing (11-29-2011)
Old 11-29-2011, 09:20 PM   #4
Member
 
Join Date: Feb 2007
Location: NW Ohio
Posts: 804
Default

My furnace died


Quote:
Originally Posted by beenthere View Post
He never fixed your furnace. Call him/that company back up and let them know. They shouldn't charge you other then for the correct fix, that they didn't do.
Thats what i would do as well.......
harleyrider is offline   Reply With Quote
Old 11-30-2011, 01:34 AM   #5
Newbie
 
Join Date: Nov 2011
Posts: 7
Default

My furnace died


Oh,
Also, if the green light on the device inside is flashing 3 times,
can anyone tell me if that means something? Furnace is a 2001 Comfortmaker 9MPT.
BobPike
BobPike is offline   Reply With Quote
Old 11-30-2011, 05:43 AM   #6
Hvac Pro
 
Join Date: Nov 2008
Location: Winnipeg, Canada
Posts: 9,256
Default

My furnace died


should have an error code legend on the back of one of the doors or by the wiring diagram or in the owners manual
__________________
"Cut it twice and it is still too short".
yuri is offline   Reply With Quote
Old 11-30-2011, 06:00 AM   #7
I'm Your Huckleberry
 
Join Date: Mar 2011
Posts: 5,620
Default

My furnace died


Quote:
Originally Posted by BobPike View Post
Oh,
Also, if the green light on the device inside is flashing 3 times,
can anyone tell me if that means something? Furnace is a 2001 Comfortmaker 9MPT.
BobPike

Low pressure switch, open when it should be closed. Longer than 30 seconds after inducer starts.

Here's the manual for your unit. Scroll down a bit to see the flash code legend.
http://icpindexing.toddsit.com/docum...4001201100.pdf
Doc Holliday is offline   Reply With Quote
Old 11-30-2011, 07:53 AM   #8
Newbie
 
Join Date: Nov 2011
Posts: 7
Default

My furnace died




Hello,
Thanks! I scrolled down and read it. But why would it be open , what can I do about it?
BobPike

3 Flashes = Low Pressure switch circuit was still sensed as open 30 seconds after the inducer was energized. System
is in 5 minute delay mode, with inducer off. After 5-minute delay, a new ignition sequence will be initiated.
(Note: SV9541Q On/Off switch in off position during a call for heat will generate this diagnostic code)
BobPike is offline   Reply With Quote
Old 11-30-2011, 08:06 AM   #9
I'm Your Huckleberry
 
Join Date: Mar 2011
Posts: 5,620
Default

My furnace died


Buy a new pressure switch. You can first try removing the tube from switch and stick a straightened paper clip in port. Same on inducer motor tube port.
Doc Holliday is offline   Reply With Quote
Old 11-30-2011, 08:21 AM   #10
Member
 
Join Date: Nov 2010
Location: N. Central Ma.
Posts: 33
Default

My furnace died


Inspect chimney for blockage first.
fitter1 is offline   Reply With Quote
Old 11-30-2011, 08:40 AM   #11
Newbie
 
Join Date: Nov 2011
Posts: 7
Default

My furnace died


1. I pulled the ducts off the furnace- so no restrictions at all now on the outtakes- plus I opened the lower cover grill and have that cover switched taped down, so the blower can suck all the air it wants- and if I trigger the blower to work as indicated in my first post- the blower does trigger on just as before, no changes, blows cold air for about 2-3 min then shuts off.
- so no restrictions on the air blowing out, side of the furnace.

2. I pull the tube off the the low pressure switch. I blew and sucked some air into it. I can hear the device clicking. So no restriction there I dont think. But there are 2 sections to the low pressure switch(es?) with 2 small hoses (I call them upper and lower) to them from the inducer, not sure which one needs diagnosing.

3. But I dont think (hard to tell?) if the draft inducer motor is working- doesnt seem to be. Maybe thats why the low pressure switch is "open"?

Help!
BobPike.
I just read the above posts- what I will do is trigger the blower again, and check to see if the inducer is working by feeling the outside exhaust outlet for air outflow.
- DONE- there is no air flowing out the exhaust- because I can see the inducer isnt running at all. The motor end that protrudes from the end of the motor doesnt turn (unless i press & twist my finger on the end and make it spin a bit. I guess this is why the low pressure switch is OPEN! but now what do I do about the inducer motor?)
- can I test the inducer motor somehow. ?
- is it a possible thermostat issue? Maybe its not tell the inducer what it needs to hear? How do I test this?

Last edited by BobPike; 11-30-2011 at 09:16 AM.
BobPike is offline   Reply With Quote
Old 11-30-2011, 06:38 PM   #12
I'm Your Huckleberry
 
Join Date: Mar 2011
Posts: 5,620
Default

My furnace died


Yup, you can literally see and hear the inducer when it runs. It should be the first thing to turn on on call for heat.

Does the inducer motor have a run capacitor attached to it? If so, you can use a meter that has Micro Farad (mfd or uf) reading capability to test the cap or you can simply remove the capacitor and take it with you to Grainger and buy the same one.

Cost will be about (most likely under) $10.

The run capacitor is the small silver canister with two (usually brown in color) wires from the inducer motor attached (plugged) into it. It would be strapped to or very near the inducer, like so:



If you do not have a capacitor then I'll walk you through how to hard wire that inducer, bypassing all boards and controls, to see if it comes on or not.

And yes, you are correct. The inducer causes a negative pressure in the tube which sucks the pressure switch(es) closed. No inducer, no pressure switch closing. No pressure switch closing, no fire.
Doc Holliday is offline   Reply With Quote
Old 11-30-2011, 06:53 PM   #13
Member
 
Join Date: Oct 2009
Location: Nebraska
Posts: 2,362
Default

My furnace died


SV9541Q is a "smart" gas valve that powers the inducer.
Marty S. is offline   Reply With Quote
Old 11-30-2011, 06:55 PM   #14
I'm Your Huckleberry
 
Join Date: Mar 2011
Posts: 5,620
Default

My furnace died


Doc Holliday is offline   Reply With Quote
Old 11-30-2011, 06:57 PM   #15
I'm Your Huckleberry
 
Join Date: Mar 2011
Posts: 5,620
Default

My furnace died


Quote:
Originally Posted by Marty S. View Post
SV9541Q is a "smart" gas valve that powers the inducer.

Where did you see that posted or is that the number for the Comfortmaker?

Doc Holliday is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Furnace Model # Feh-015-04 clicking but not turning on? haimei HVAC 1 12-14-2010 05:01 PM
Payne PG9YAB high efficiency 95% furnace water draining problem jchen64 HVAC 9 12-06-2010 06:42 PM
Carrier Infinity 69 Trouble Code 42 bodya1 HVAC 4 12-05-2010 06:43 PM
Furnace not firing jax HVAC 5 02-22-2009 12:41 PM
Problem with Trane gas furnace quovadis HVAC 17 12-22-2008 01:12 PM




Top of Page | View New Posts

Copyright © 2003-2014 Escalate Media. All Rights Reserved.