The Gear Box

Welcome to the Gear Box!  Please use the message boards for technical questions.


 

joanfenn

2020 Nov 26 13:40:46
Wow hello Fredric, nice to see you again. Happy thanksgiving to you
 

Stripe

2020 Nov 26 12:51:53
Happy Thanksgiving!
 

ClydesdaleKevin

2020 Nov 26 12:26:33
Happy Thanksgiving everyone!!!
 

Oz

2020 Nov 25 01:26:28
Thank you Joan!
 

joanfenn

2020 Nov 25 00:42:41
Have a good and safe one Mark.  We already had ours last month but will be with you in spirit.  And drooling also. 
 

Oz

2020 Nov 24 16:29:55
Happy Thanksgiving everyone!
 

Elandan2

2020 Nov 22 13:31:55
Ah, that's better. Thanks for all the great improvements Mark. :)ThmbUp
 

Oz

2020 Nov 22 05:15:11
You're welcome!
 

TerryH

2020 Nov 22 03:48:06
Yes - seems to be up and running. Missed it while gone. Thanks Mark!
 

Oz

2020 Nov 17 03:32:58
I know, right?  The changes to the site are coming along, but not without its glitches, of course.  Always a learning curve...
 

joanfenn

2020 Nov 16 18:01:10
This one is good also.  Just nice to chat again
 

Oz

2020 Nov 15 13:09:30
 :D
 

joanfenn

2020 Nov 15 02:49:50
I am used to this one, but not to old enough to learn
 

Oz

2020 Nov 15 02:36:28
Do you like this way better, or the balloon box version?
 

Oz

2020 Nov 14 23:02:46
Thank you!   :)clap
 

Oz

2020 Nov 14 23:01:19
Not as compact with the text, but maybe a bit more "fun" and "chatty"?
 

joanfenn

2020 Nov 14 23:01:18
carry on sir, you are doing a great job :)ThmbUp
 

Oz

2020 Nov 14 23:00:29
LOl!  :D
 

joanfenn

2020 Nov 14 22:58:41
yes it is growing on me now :)
 

Oz

2020 Nov 14 22:58:06
I kinda like it.
 

joanfenn

2020 Nov 14 22:57:57
And I wasn't going to say anything but your are special, not odd
 

joanfenn

2020 Nov 14 22:56:46
It will work just have to get used to the layout
 

Oz

2020 Nov 14 22:55:53
Well, I'm odd.  So... yeah, kinda fits just right.
 

joanfenn

2020 Nov 14 22:55:47
Funny layout I mean.  But nice to be able to chat again
 

Oz

2020 Nov 14 22:55:24
Just transitioned to the new portal system.  I have a lot to recreate yet, but it won't take long. How do you like the new chat room?
 

joanfenn

2020 Nov 14 22:54:24
This is odd
 

Oz

2020 Nov 14 22:53:50
Hi Joan!
 

joanfenn

2020 Nov 14 22:52:54
Hello!!

Author Topic: Furnace Issue - Suburban NT-30 won't light  (Read 15060 times)

1 Member and 1 Guest are viewing this topic.

Offline vincewarde

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Furnace Issue - Suburban NT-30 won't light
« on: September 06, 2012, 02:45 AM »
I have a Suburban NT-30 furnace that is giving me fits.  Before coach went into storage, it worked.  Then I got a wasp's nest in the blower.  I cleaned that out and it now spins up fine - but won't light.
So, next I inspected and replaced the igniter (it was badly corroded).  I can hear it firing, but still no flame.
I next checked the gas valve.  I can both hear it opening and a test light shows that both magnets are getting power.
All I can think to do is tear out the plumbing and make sure it is clear - and perhaps check to see that the valve is actually opening.  Yes, there is gas and yes, the valve to the furnace is open :)
Does anyone else have any ideas?  Thanks!
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Offline DonD

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Re: Furnace Issue - Suburban NT-30 won't light
« Reply #1 on: September 06, 2012, 08:48 AM »
I put mine on the bench and powered it up. It turned out to be the sail switch wasn't free, was hanging up a bit. I freed that and exercised the gas valves and she woks well now.
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Don and Mary
 2000 TC1000 Bluebird bus conv.

Offline vincewarde

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Re: Furnace Issue - Suburban NT-30 won't light
« Reply #2 on: September 06, 2012, 11:56 AM »
According to the information in the manual, the sail switch has to be working for the gas valve to be energized.  Therefore, I don't think that is the problem.  I am really stumped.  Hm?
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Offline DonD

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Re: Furnace Issue - Suburban NT-30 won't light
« Reply #3 on: September 06, 2012, 03:46 PM »
My valves wouldn't pass air when blown into but a few cycles and they freed up. Blow by mouth or very low pressure.
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Don and Mary
 2000 TC1000 Bluebird bus conv.

Online joanfenn

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Re: Furnace Issue - Suburban NT-30 won't light
« Reply #4 on: September 06, 2012, 07:02 PM »
I know a lot of guys that have valves that pass air,  usually at the most inconvenient time too. W%
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Offline OldEdBrady

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Re: Furnace Issue - Suburban NT-30 won't light
« Reply #5 on: September 06, 2012, 08:14 PM »
It's not very nice to make fun of us old folks.   W%
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Offline Oz

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Re: Furnace Issue - Suburban NT-30 won't light
« Reply #6 on: September 07, 2012, 01:27 PM »
Joan, you said exactly what I was thinking too... LOL!
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Offline audioguyinMI

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Re: Furnace Issue - Suburban NT-30 won't light
« Reply #7 on: September 10, 2012, 02:00 AM »
You say you can hear the igniter, but  can you see it?  On mine there's an inspection window and I can see it sparking when it's working. 

If you can't SEE yours and the gas is OFF, you could safely remove the igniter, leave it connected and place it on something non conductive and preferably non flammable, and verify that the thing IS actually making sparks, and not just noise.


If it is, then the only thing left is the plumbing and/or the valve itself.
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Offline vincewarde

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Re: Furnace Issue - Suburban NT-30 won't light
« Reply #8 on: November 15, 2012, 12:35 AM »
Well, I finally recovered enough from most recent back problem to be able to check out the furnace valves.  When I put 12v to the valves with a jumper set up they open right up.  Tubes are clear too.  Next I'll put it back in the coach and see if I can get it to light...... if it doesn't fire up I'll check the igniter for spark.
In any case, I'll post the results......
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Offline DonD

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Re: Furnace Issue - Suburban NT-30 won't light
« Reply #9 on: November 15, 2012, 08:39 AM »
Further troubles with mine so I benched it and found the grounding wire was bubbling on both sides of the plug. In the interest of safety I replaced it, caught a sale at PPL. EZ swap, no worries now.
 
I'll be watching with interest to see what you find.
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Don and Mary
 2000 TC1000 Bluebird bus conv.

Offline vincewarde

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Re: Furnace Issue - Suburban NT-30 won't light
« Reply #10 on: November 16, 2012, 03:42 PM »
Further troubles with mine so I benched it and found the grounding wire was bubbling on both sides of the plug.

I assume you are talking about the connection on the valve - correct?
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Offline DonD

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Re: Furnace Issue - Suburban NT-30 won't light
« Reply #11 on: November 16, 2012, 07:26 PM »

No, the feed, both sides of the plug so I knew it wasn't a bad connection in the plug.
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Don and Mary
 2000 TC1000 Bluebird bus conv.

Offline DaveVA78Chieftain

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Re: Furnace Issue - Suburban NT-30 won't light
« Reply #12 on: November 22, 2012, 07:16 PM »
You will not get ignition spark if the sail switch is not engaged so given you are getting spark the sail switch is ok.
Have you purged the air out of your gas lines?  Sitting over the winter you usally end up with air in the gas line.  First thing is to get the burners on the stove working.  This will remove most of the air leaving only the line from the main supply line to the furnace unpurged.  Getting the air out of that line may take 20 or more tries depending the length of the line.
 
An in-depth description of furnace operation: http://www.classicwinnebagos.com/forum/index.php?topic=2640.msg5117#msg5117
 
You have a DSI model furnace.
 
Dave
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Offline vincewarde

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SOLVED: Furnace Issue - Suburban NT-30 won't light
« Reply #13 on: January 05, 2013, 09:52 PM »
OK, it's been a while, but we finally solved the problem today.

A few weeks ago, I pulled the furnace and took it apart.   I used a battery to cycle the valves a number of times.  They opened just fine.  So, at a total loss to understand what the problem, I put it back together.

Today we put the furnace back into place and hooked it up.  We ran the stove to make sure the gas line was as free of air as we could make it.

Then the big moment:  We fired it up.  It lit on the first try!!!!   :)clap

I can only assume that cycling the valves freed them up.

Thanks to everyone who offered advice!   
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Online moonlitcoyote

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Re: Furnace Issue - Suburban NT-30 won't light
« Reply #14 on: October 17, 2020, 12:32 PM »
I need to know more about tis cycling the valves part. My furnace is exactly 2 years old and it wont light. We have spark, lots of propane and no mud dobber nests in it. I cant find the problem anywhere.
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Offline Oz

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Re: Furnace Issue - Suburban NT-30 won't light
« Reply #15 on: October 17, 2020, 01:36 PM »
Hi MJ, good to see you again.
Take a look at the topic,
"Anatomy of a furnace".

https://www.classicwinnebagos.com/forum/index.php?topic=2640.msg5110#msg5110

This should help.
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Online moonlitcoyote

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Re: Furnace Issue - Suburban NT-30 won't light
« Reply #16 on: October 17, 2020, 01:46 PM »
I did thank you. I need someone that KNOWS furnaces. What I have found is that I can blow through the gas valve IF I power both sides. BUT if I try to blow through it while the electrode is clicking I cant. It seems to be opening for just a second then closing again.
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Online moonlitcoyote

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Re: Furnace Issue - Suburban NT-30 won't light
« Reply #17 on: October 28, 2020, 03:37 PM »
Still no takers on this topic? I changed out the gas valve today after waiting to get it in the mail and still no heat. Everything seems to run perfectly except we get no heat. The fan comes on, the thermocouple starts sparking, no ignition so it goes through the sparking sequence 2 more times and still no ignition. Have run the stove to be sure there is no air in the lines. There is no gas smell from the exhaust. I'm at a total loss as to what to do next.
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Offline Elandan2

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Re: Furnace Issue - Suburban NT-30 won't light
« Reply #18 on: October 28, 2020, 04:09 PM »
Here is the service manual for the Suburban furnaces.
http://techsupport.pdxrvwholesale.com/wp-content/uploads/2017/09/Suburban-Dynatrail-Furnace-Model-NT34SP-Service-Manual.pdf
Page 11 has the troubleshooting instructions for electronic ignition models. It seems like your problem may be # 5. Also, on the next page, item C might help you track down the problem.
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Rick and Tracy Ellerbeck

Online moonlitcoyote

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Re: Furnace Issue - Suburban NT-30 won't light
« Reply #19 on: October 28, 2020, 05:02 PM »
Thanks, I have done everything except check the gas pressure and the limit switch. I was told that if the limit switch was bad it would shut off AFTER starting. Mine wont even start.

But I am confused about this step: If sparking is audible approximately 15 seconds after the blower starts, but no ignition,
check the high-tension wire for continuity, grounding and secure connections. Repair if
necessary.

If there was a problem with the wire would it still spark?
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Offline Oz

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Re: Furnace Issue - Suburban NT-30 won't light
« Reply #20 on: October 29, 2020, 01:58 AM »
If the switch has power and good ground, and does that, then the switch is malfunctioning.

If it has power and good ground and it's not even starting, then it's not functioning at all. 

Check the ground and that it is, in fact, getting power.
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Offline Oz

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Online moonlitcoyote

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Re: Furnace Issue - Suburban NT-30 won't light
« Reply #22 on: November 25, 2020, 09:50 AM »
If the switch has power and good ground, and does that, then the switch is malfunctioning.

If it has power and good ground and it's not even starting, then it's not functioning at all. 

Check the ground and that it is, in fact, getting power.

Which switch is this? I still have no heat and it's going to be in the 30's this week.
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Offline Oz

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Re: Furnace Issue - Suburban NT-30 won't light
« Reply #23 on: November 25, 2020, 11:47 AM »
By following the information referred to several times, and your description, you have gas supplied and you have spark.  But, it sounds like you have no gas to the spark.  This is controlled by the gas valve.  If you know there is gas going to the valve, the ignitor is working, but nothing lights, then there must not be anything to light.

Again, referring to the Anatomy of a furnace topic which covers all of this.
https://www.classicwinnebagos.com/forum/index.php?topic=2640.msg5110#msg5110

Dave laid out the process very well.  Scroll down to "Blower runs but furnace fails to ignite".


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Online moonlitcoyote

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  • Member since: 2012
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  • Model: Chieftain 27RU
  • Chassis: Chevy
  • Engine: 454
Re: Furnace Issue - Suburban NT-30 won't light
« Reply #24 on: November 25, 2020, 07:05 PM »
I replaced the gas valve, working on limit switch now, I went through that post and also a bunch of youtube videos and anything else I could find. Just haven't figured out the problem.
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