Heil gas furnace- no hot surface ignitor or heat

Reply

  #1  
Old 12-06-16, 09:28 AM
A
Member
Thread Starter
Join Date: Dec 2016
Posts: 13
Received 0 Votes on 0 Posts
Heil gas furnace- no hot surface ignitor or heat

I have a Inter City Product Gas Furnace that is a 90% Model Number NUGM100EHA1. The furnace one day stops working. This is what happens.

The inducer will go on when it calls for heat and then nothing. It will just keep running forever and nothing happens.

What I have already done to try to fix the problems is, replaced a new smartvalve, replaced a new control board, replace a new hot surface ignitor, and a new pressure switch. I tested the limit switch and it's fine. I am really to the point where I have no idea what to do and what to try next.

I had a furnace guy come out and take a quick look to see if they can figure it out and they said everything looks right.

Any ideas?
 
Sponsored Links
  #2  
Old 12-06-16, 09:37 AM
R
Member
Join Date: Oct 2016
Posts: 1,861
Received 103 Votes on 97 Posts
When the furnace is attempting ignition is the board displaying any errors?
 
  #3  
Old 12-06-16, 09:49 AM
A
Member
Thread Starter
Join Date: Dec 2016
Posts: 13
Received 0 Votes on 0 Posts
I checked on the control board and there is no such blinking light to show the error on the model that we have.
 
  #4  
Old 12-06-16, 09:55 AM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 59,069
Received 1,109 Votes on 1,029 Posts
Welcome to the forums.

Good to see you have plenty of spare parts on hand now.

If the pressure switch doesn't prove (close) the heating cycle can't continue.
The only service info I've found so far shows a spark ignition/pilot but you said yours has a hot surface igniter ?

It looks like you have a condensing furnace that is know for cracked heat exchangers or a rivet problem in the assembly. You may have a clogged drain line upsetting the vacuum from the inducer. The little nipple on the inducer could also be clogged. It's just a little pinhole.

Name:  DI nipple.jpg
Views: 241
Size:  4.8 KB

Your furnace guy should check the vacuum to the pressure switch with a manometer.
 
  #5  
Old 12-06-16, 10:06 AM
A
Member
Thread Starter
Join Date: Dec 2016
Posts: 13
Received 0 Votes on 0 Posts
You are probably right. I think when I changed the ignitor it had a thing that should glow with another stick (I apologize for the lack of technical terms). AND YES, I have MORE than enough parts. I feel like I just bought a new furnace that doesn't work.

For some reason the person that installed the furnace years ago never actually ran a hose from the inducer to the pressure switch. The pressure switch was just there and did not even have power running to it. I put the NC and C on it now and the rubber tubing where it's suppose to be. It worked for years without it.

Do you know what the manometer should be or where do I look? When the inducer goes on, I don't here a click where I think I should from the pressure switch. Like you said it might not be drawing enough vacuum.

As a test I try to "jump" it last night with NO (or NC I forgot) and C connecting wire to see if it can bypass the pressure switch and it didn't work either.

SO thankful for any input from anyone and the replies that I have received so far. Thank you so much.
 
  #6  
Old 12-06-16, 10:14 AM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 59,069
Received 1,109 Votes on 1,029 Posts
The furnace should not have been able to work without the pressure switch connected and working properly. This is a vital part of the process and a control board usually can't be set to bypass it. The manometer is a test gauge that connects between the draft inducer and pressure switch.

There is very little info on that unit.
I can use the control board model number and pictures are always helpful.

http://www.doityourself.com/forum/el...-pictures.html
 
  #7  
Old 12-06-16, 10:33 AM
A
Member
Thread Starter
Join Date: Dec 2016
Posts: 13
Received 0 Votes on 0 Posts
Name:  s-l1600.jpg
Views: 328
Size:  51.7 KB

This is the picture where I bought the control board. I wasn't able to get a picture of right now. I am pretty sure "no advertising" so I crossed out the company. I don't know if you need that.

I thought it was weird that it didn't work with the pressure switch.
 
  #8  
Old 12-06-16, 10:35 AM
R
Member
Join Date: Oct 2016
Posts: 1,861
Received 103 Votes on 97 Posts
The pressure switch is installed and wired from the factory. It is not a field installed part. Which means if it was inoperable someone bypassed it, which is very unsafe.
Someone should do a thorough heat exchanger inspection before any more work is done.
 
  #9  
Old 12-06-16, 10:38 AM
A
Member
Thread Starter
Join Date: Dec 2016
Posts: 13
Received 0 Votes on 0 Posts
I plugged the pressure switch back on and make sure it is connected now. Safety is important.
 
  #10  
Old 12-06-16, 10:39 AM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 59,069
Received 1,109 Votes on 1,029 Posts
The company name on a part like that is ok. It's different if you were a company selling it.
I need the board part number.
 
  #11  
Old 12-06-16, 11:26 AM
A
Member
Thread Starter
Join Date: Dec 2016
Posts: 13
Received 0 Votes on 0 Posts
Below is the board number:

Honeywell Fan Control Board ST9120G 4012 ST9120G4012

Yah I am definitely not selling it. I bought all the parts and I have no idea how to get the furnace going
 
  #12  
Old 12-06-16, 12:00 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 59,069
Received 1,109 Votes on 1,029 Posts
I'm looking at the general replacement for that board. It can be set up several ways. The pressure switch is not connected into the board but in the line to the gas valve. That's how it was able to be not used.

I don't see any hot surface igniter mentioned. Are you sure you don't have an intermittent ignition system ? That would be an igniter lights a pilot first and then the burner.

honeywell links/combustion/st9120u/install/69_0644.pdf
 
  #13  
Old 12-06-16, 12:10 PM
A
Member
Thread Starter
Join Date: Dec 2016
Posts: 13
Received 0 Votes on 0 Posts
Name:  Q3400A-c3.jpg
Views: 565
Size:  13.2 KBI'll link the picture of the pilot thing.

My above ignitor is connected to my smartvalve.
 
  #14  
Old 12-06-16, 12:14 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 59,069
Received 1,109 Votes on 1,029 Posts
Thanks. That is a HSI and a flame sensor rod.
 
  #15  
Old 12-06-16, 12:18 PM
A
Member
Thread Starter
Join Date: Dec 2016
Posts: 13
Received 0 Votes on 0 Posts
Is it possible my control valve is not giving power to the HSI? (thank you for the technical terms for the part)

Do you want a picture of the smartvalve?
 
  #16  
Old 12-06-16, 12:30 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 59,069
Received 1,109 Votes on 1,029 Posts
A picture of the valve would be good as well as its model number.

Everything I'm finding is not correlating with what you have.
The fan timer board doesn't list an HSI as an option.

I'll know better when I see what you have.
 
  #17  
Old 12-06-16, 12:37 PM
A
Member
Thread Starter
Join Date: Dec 2016
Posts: 13
Received 0 Votes on 0 Posts
This is my smartvalve

Name:  20160315_051256190_iOS.jpg
Views: 518
Size:  35.3 KB
 
  #18  
Old 12-06-16, 01:08 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 59,069
Received 1,109 Votes on 1,029 Posts
Ok..... just for the record. You have an intermittent ignition system. The HSI lights the pilot which lights the burner.

The following is the manual/instructions for the smart valve.
honeywell_links/combustion/universal_smart_valve/install/69_1270.pdf

This is going to get involved...... do you have a voltmeter ?
 
  #19  
Old 12-06-16, 01:17 PM
A
Member
Thread Starter
Join Date: Dec 2016
Posts: 13
Received 0 Votes on 0 Posts
Yes I just bought a voltmeter. I did not know you can set up the furnace so many different ways with the setup I have. Interesting. Thanks for the PDF links.
 
  #20  
Old 12-06-16, 01:23 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 59,069
Received 1,109 Votes on 1,029 Posts
Ok.... here's the diagram for your fan timer and smart valve.
Click on it for larger view.



With a meter set to measure 24vac....
1) Confirm 24vac at XFRMR and SEC in orange circle. If yes.... go on.
2) Confirm 24vac on the C and R terminals where the thermostat connects. If yes..... go on.

I don't know what colors you have there as I don't have a service manual. So... look at the locations on the 4 pin plug.
3) Confirm 24vac on the red and blue wire AT the smart valve. If yes.... go on.
4) Attach a jumper to connect R and W where the stat connects. This will turn on the draft inducer blower. Check for 24vac from blue to pink wire AT valve. You can leave the pressure switch out of line just for this test.

Depending on big your probe tips are..... you may need to use a small brad or piece of wire to get down into the pin. The plug must be in when testing. Also.... turn off gas while testing.
 
  #21  
Old 12-06-16, 01:29 PM
A
Member
Thread Starter
Join Date: Dec 2016
Posts: 13
Received 0 Votes on 0 Posts
OH MY GOSH you're so awesome. I think I might have to do a wire insert cause the volt meter is not long enough. I'll give this a try.
 
  #22  
Old 12-06-16, 09:30 PM
A
Member
Thread Starter
Join Date: Dec 2016
Posts: 13
Received 0 Votes on 0 Posts
Thanks Pete!!!!!!

So I went through the process tonight. Everything over 24 VAC except for step #4 (Attach a jumper to connect R and W where the stat connects. This will turn on the draft inducer blower. Check for 24vac from blue to pink wire AT valve. You can leave the pressure switch out of line just for this test.)

I think it could be because I didn't stick the wire down enough but got up to 20.5VAC on #4.

I think it is getting power for sure. I also clean out the inducer hole thing. It didn't look like it was clogged. Greatly confused.

 
  #23  
Old 12-08-16, 11:42 AM
A
Member
Thread Starter
Join Date: Dec 2016
Posts: 13
Received 0 Votes on 0 Posts
Thanks everyone for their comments and input. I am going to bit the bullet and get a Heil dealer out. Completely out of ideas.
 
Reply
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


Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: