"stronger" Igniter, re-igniter, spark generator a problem?

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  #1  
Old 12-09-09, 04:31 PM
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Smile "stronger" Igniter, re-igniter, spark generator a problem?

Hello,

I have a Carrier gas Furnace, (intermittent pilot) where this type LH33WZ503 of igniter is recommended:
Carrier LH33WZ503 Spark Ignitor - eBay (item 120503371417 end time Jan-06-10 09:44:05 PST)
http://cgi.ebay.com/Carrier-LH33WZ50...08191006r20560

The specs say: 24VAC, 8mA.
Accidentally, I have ordered this one:
Product Group Details
http://www.johnstonesupply.com/15/ta...duct_group=548
Its specs say: Electrical rating: 24/117VAC, 0.1A.

My question: Is the difference in current (not 8mA but 0.1A or I'd say 100mA) a problem for the furnace or the board or my transformer?
My Furnace: Carrier Model 394 GAW, Series A from 1975 (!)
Gas Valve: BDP 646AW

Thanks for your help!!
Sebastian
 
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  #2  
Old 12-09-09, 04:57 PM
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Ignitors

The two items are not the same. The one from Johnstone is intended, I believe, to be used on a standing pilot system. The e-bay item is to light the pilot on a call for heat where the pilot does not stay lit all the time.
 
  #3  
Old 12-09-09, 05:11 PM
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I agree with Grady, they are intended for different purposes.

Whether it will function properly in the Carrier furnace I'm not sure. I wouldn't be surprised if it would.

The spark module is energized while the pilot switch is in the "cold" position, and switched off when the SPDT switch changes to the "hot" position when heated by the pilot light.

That's pretty simple.


Still I would have recommended using a spark module intended for this furnace application, especially for a DIYer. Generally speaking, it's smart for DIYers to keep things as simple as possible, in my experience, even if it costs a few additional dollars.
 
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Old 12-09-09, 11:36 PM
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Unhappy lifetime of igniter, harm to my furnace, boarg or transforner

Hello all,
thanks Grady and SeattlePioneer for your answers.

Do you think using the Johnstone would shorten the lifetime my furnace, board or transforner?

Moneywise, the ebaypart is even cheaper than the Johnstone part, it is just that I found out about it later, unfortunately - and, that ebay has no warranty.

For my safety, I put an additional in-line fuse-holder from automotive between transformer secondary and board, so I hope, that is a little protection for the board.

I am also curious if everything works out, esp. as I have intermittend and not standing pilot...
Thanks, guys for your thoughts,
I'll let you know,
Sebastian
 
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Old 12-09-09, 11:40 PM
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Originally Posted by turtle_99 View Post

Do you think using the Johnstone would shorten the lifetime my furnace, board or transforner?


No.

---------------------------------------------------------------

-

-
 
  #6  
Old 12-09-09, 11:47 PM
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the specs of the igniter

wow, that was quick, I see, I am not the only one, still browsing this site.. :-)

Question: But was does the difference in the amps say:

doesn't the Johnstone "draw"/suck more power for every ignition, as it has 100mA and why is the ebay article (the OE replacement) so much "weaker" with only 8mA? I would worry, if that would light up at all.

Today I looked at print on my dead igniter, that said, it was produced only 3 years ago, and it had 75mA. As I mentioned, Carrier recommends the one with 8mA...

(?)
 
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Old 12-09-09, 11:50 PM
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Don't quibble about differences that don't matter. The circuit board has ample power available to operate the 100MA spark generator.
 
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Old 12-09-09, 11:53 PM
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Thumbs up how I fired up my furnace, without igniter

For the ones interested:

I was very thrilled, as I found out, how easy I can manually fire up my furnace w/o working igniter:

I only disconnected the igniter cable, not the "three wires", had the digital thermostat calling for heat, then switched the power for the furnace "on", had a lighter at the pilot and I was able to light it up,

because finally, there was gas flowing to my pilot... before, with every wire in place, and the igniter most likely going south, the pilot gas stopped after one second...

Tomorrow, I get the new igniter (the 100mA) and will use that part, hope it works. Would you recommend, rather switch to the 8mA igniter?

Good n8!
Sebastian
 
  #9  
Old 12-09-09, 11:57 PM
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thanks

Originally Posted by SeattlePioneer View Post
Don't quibble about differences that don't matter. The circuit board has ample power available to operate the 100MA spark generator.
thanks Pioneer, I am new "on furnaces" and I did not know, what matters or what is fragile, or what equipment should fit exactly, like given in the OE specs, that's why I ask...

Just want to avoid loosing any other equipment, my furnace is from 75 (!), pretty amazing, that it is still working anyway :-)
...
 
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Old 12-10-09, 12:23 AM
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Originally Posted by turtle_99 View Post
thanks Pioneer, I am new "on furnaces" and I did not know, what matters or what is fragile, or what equipment should fit exactly, like given in the OE specs, that's why I ask...

Just want to avoid loosing any other equipment, my furnace is from 75 (!), pretty amazing, that it is still working anyway :-)
...

I understand. That's why I recommend that DIYers use parts specified by the manufacturer rather than cobbling up compromises. Compromises require more judgment and skill to do successfully.

But in this case the additional current used wont have an impact.
 
  #11  
Old 12-12-09, 12:56 PM
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blue spark does not ignite Pilot (IP)

-I bought the new igniter, see below
- installed it, after calling for heat, blue sparks comes on
- gas flows to the pilot (burner)
- when I test it, while the spark is igniting, I can fire up the pilot gas with a lighter
- it seems to be enough gas, the pilot burns blue


What can I do, so the spark ignites the pilot gas automatically??
 
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Old 12-12-09, 02:37 PM
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Have you cleaned the pilot burner and pilot orifice? That's the most common reason the Carrier three wire pilot system doesn't work. It can create a pretty wide variety of symptoms, including failure to light the pilot.

If not, you need to loosen the brass ferrule at the bottom of the pilot switch with a 7/16" wrench to get at the pilot orifice, and clean it --- the wire from a wire brush works well.
 
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Old 12-12-09, 02:51 PM
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flame not igniting

yes, i had it out 10 times maybe, cleaned it, cleaned the contacts inside the 3-wire unit, tested for continuity....
 
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Old 12-12-09, 02:56 PM
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gas amount

I don't think, it is too little gas, however, I don't know, if I should adjust at the main gas valve?

I've read in another thread somewhere, a back-log/ too much gas could be bad as well for the flame, b/c needed oxygen for igniting would be "cut-off"- does that makes sense...?

I've cleaned a lot, my last resort would be replacing the 733B or adjusting at the main valve?
I've never done that. What should the pilot flame look like, right now, it is maybe 3-4 inch high, blue... when I ignite manually
 
  #15  
Old 12-12-09, 04:52 PM
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rocker, teeter-totter of pilot burner

hi, now I have the pilot burner coming on with a few sparks, but the main burner is not coming on,

- I guess it is because of the 3-contact rocker, teeter-totter of pilot burner.
- I tried to adjust the pilot burner on the main gas valve (unscrewed security screw, tried to adjust inside), could that be the cause, that the main burner don't come on again? I don't think so..(?)

Does anybody have a detailed description how the rocker inside the pilot burner 733B should be adjusted/bend...??

Thanks guys!!!
 
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Old 12-12-09, 05:39 PM
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Pilot Adjustment

Most gas valves today do not have a pilot adjustment. You are probably adjusting the main valve. Not good. You need a manometer to set the gas to it's spec'd pressure. Here's how to make one. RV U Tube Manometer
Disregard the pressures mentioned in the article as they are for propane in an RV.
 
  #17  
Old 12-17-09, 12:03 PM
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And what pressure needs my gas valve (Model 646 A-X)

The flame of the three main burners are very strong and seem to be a little too yellow.

What would be a reasonable price to check the pressure by a professional?

my furnace (58GS075-301) says:

Temp rise Static press.
45-75 0.5
55-65 0.5
55-85 0.12

Moreover it says :
Input: 75000 BTU/hr
Bonnet capacity: 60000 BTU/hr

natural gas

Thanks guys!
 
  #18  
Old 12-17-09, 12:14 PM
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Manifold Press: 3.5 In. WC. (I canīt read the sign very well, I guess it is 3. 5, I can aonly read "3 5")
For my furnace, I wouldn't know, how To adjust the main valve with this R-V manometer. Has anybody done it like this?

Originally Posted by turtle_99 View Post
And what pressure needs my gas valve (Model 646 A-X)

The flame of the three main burners are very strong and seem to be a little too yellow.

What would be a reasonable price to check the pressure by a professional?

my furnace (58GS075-301) says:

Temp rise Static press.
45-75 0.5
55-65 0.5
55-85 0.12

Moreover it says :
Input: 75000 BTU/hr
Bonnet capacity: 60000 BTU/hr

natural gas

Thanks guys!
 
  #19  
Old 12-17-09, 12:41 PM
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Where in Ca do you live? If PG&E area call them. If down so, call the Gas co and request a furnace check. I don't feel comfortable giving step by step with something as important as this. I mean no disrespect, only thinking of your safety.
 
  #20  
Old 12-18-09, 10:47 AM
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I have used those robertshaw boxes on carrier furnaces before. They work well and I can't see how it can affect the board.
 
  #21  
Old 12-18-09, 01:43 PM
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short circuit adjusting the electrode

Now, I innadvertently made a short, adjusting the electrode, I guess, it touched the metal somewhere:

Now:
-the fuse blows and the fan starts everytime I start the furnace/call for heat
- if I disconnect spark wire and 3 wire pilot, fuse is OK
- if I only disconnect spark wire, fuse blows.

?Any Ideas?? I have a ground somewhere I guess, what should I do?

Thanks for your help
 
  #22  
Old 12-18-09, 02:53 PM
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This reminds me of "The Hunt For Red October" where the Soviet diplomat thanks the American diplomat for help in dealing with a sunken submarine and then says that they have lost track of another sub.


A common way of sorting out a short is to disconnect everythin involved and then test each wire or part for a short while reconnecting things one by one.

Presumably no short exists if the pilot switch is disconnected and the thermostat is turned up. That means you are OK in the circuit through the W terminal.

From there, the normally closed switch sends voltage on green wires to the spark module and terminal 5 of the gas valve (at least according to the cicuit diagram below)

So I'd disconnect those two wires and use an ohmmeter to see if the pilot switch is grounded and whether either of those two connections are grounded.

One of them probably is.



Seattle Pioneer
 
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Old 12-18-09, 02:57 PM
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  #24  
Old 12-18-09, 03:25 PM
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thanks, with my digital multimeter, i can't really tell:

-I disconnected power,
-disconnected wire 5 on gas valve and t1 at the spark box

do you have any other recommendations?

Can my newly purchased pilot burner be faulty? When taken off, green (spark) and yellow (pilot) connect (have continuity)...seems OK, right?
 
  #25  
Old 12-18-09, 04:11 PM
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checked for continuity

hi Seattle,

I went through the plan and checked basically everywhere for continuity:
from gas1 to 4
gas 2 to 3
gas 3 to 1 or white on the igniter
grn from pilot to 5
all seem to have good contact or continuity...
 
  #26  
Old 12-18-09, 05:40 PM
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Originally Posted by turtle_99 View Post


-disconnected wire 5 on gas valve and t1 at the spark box

With these wires disconnected, you need to see if you still have a short to ground.

The correct way to do that would be to use your muiltimeter to measure the resistance to ground.


I suppose if you want to risk another fuse you can turn on the power and the thermostat and hope....




Seattle Pioneer
 
  #27  
Old 12-18-09, 06:05 PM
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I think both are, i have my digital ohm meter on 20k and it shows 0.00 or nearly 0.00. It should not? but how can that happen? it should not, right?

If I see that right, the spark box and terminal 5 both are connected to ground..

How can I fix this?
 
  #28  
Old 12-22-09, 01:11 AM
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still not igniting

Hey guys,

I wanted to update especially Seattle on my progress so far.
"red october" is back :-)

-After my short a few days ago, I guess the pilot burner (or the 3 wire element 733B or 680 005) needed a day to "cool off" because I did not change anything

- I took the pilot out and inspected, as the 3 wire was cold, the spark and the pilot gas wire were having continuity, as it's supposed to be and the spark igniter and all other wires seemed to be OK

- so I gave it a shot (with my last 3 amps fuse) and, yes, everything working, except the pilot gas was not igniting by the spark.

- tomorrow I will make the gap a little wider, lets see, if that slows down the spark frequency and makes the (fewer) sparks more powerful, so my idea...

-As I measured, I guess my 24V transformer was gone...I put the old one in again and now I have a slight "humming" after the heating cycle is completed, any suggestions?

Thanks all for your help, I will discuss "the gap" in a separate thread

turtle
 
  #29  
Old 12-22-09, 11:39 AM
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Unhappy Aluminium tubing

Hello,

one last idea would be the aluminium tubing coming from the main gas valve to the pilot.

Lets say, the tubing is also from '75, does anybody believe it could be too corroded inside to let enough gas flow?

I took the tubing out once and blew through it to make sure no dust inside, it seemed pretty clean... (?)

Should I post a photo..?
 
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Old 12-22-09, 12:21 PM
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I thought everything was working OK after your earlier post, Turtle. That's not the case?

What's the current problem, if any?


I've never seen the pilot tubing get plugged or corroded. The pilot orifice pretty reliably gets plugged and needs cleaning after a few years, and should be cleaned annually.
 
  #31  
Old 12-23-09, 01:02 PM
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Unhappy what's still wrong

Hi Seattle,

thanks, for still responding to my thread.

1. The gas sent to the pilot does still not ignite by the sparks

2. other than that, everything should be working, see one of the last posts (-thermostat calls for heat
- pilot gas flows (new pilot)
-spark comes over, blue (new spark gen)
-after I light manually:
- burner come on after maybe 20 to 40 s
-blower kicks in
- gas stops, later blower stops)

Problem: If Pilot is not igniting, I can have an explosion, because spark gen keeps sparking and pilot gas flows, until I light manually, so to be safe after every heating cycle I shut down the whole thing, gas and electricity...
 
  #32  
Old 12-23-09, 01:41 PM
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When replacing the pilot switch, you may need to play around a bit with how the electrode is located with respect to the pilot flame. I'm supposing you reused the existing electrode, which would be the usual practice unless some kind of cracking, deterioration or wear is observed on the electrode.

Getting the electrode in the right place can require a little experimentation to get good ignition of the pilot burner.

So give that a try and see what happens.

You can try a little judicious bending of the electrode with a pair of needle nose pliars. I've never had the electrode break off when I did that, but there is some risk of it I suppose.

I'd start by checking to see that the electrode is properly mounted on the pilot burner, though.
 
  #33  
Old 12-23-09, 02:15 PM
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Smile pilot video youtube

HI Seattle,

yes, I tried that so often already, here is a video of the furnace and the pilot:

YouTube - Carrier 58GS075 Pilot 733B or 680005 not igniting , gas pilot not starting, gas furnace


maybe that helps a bit, when you see the video...
but thanks for your suggestions, I did exactly the same, re-used the old electrode, adjusted with needle-nose pliers...
 
  #34  
Old 12-23-09, 04:51 PM
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I#ve solved it! thanks for your help!

Hi Seattle,

I#ve solved it!

The spark electrode gap was the key, finally, I will post a video later:

In one direction the gap had to be 1/4 inch, which seemed always very wide for me, but now the flame ignited literally in a (one) second.

My conclusion would be that the gap has to be that wide, so high enough voltage can build up, otherwise, with smaller gap, it sparks more often but not that strong,

Thanks for all your help of everybody who posted! I will post a new youtubelink and mybe a pic of the gap and the "mistreated" electrode later.

Merry X-mas to all of you!
 
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