HSI Resistance Conflict?


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Old 11-22-21, 07:33 PM
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HSI Resistance Conflict?

Carrier Weathermaker 8000 - Model #: 58WAV090-GC Serial #: 3292A12626 -- Manu March 2, 1992 - now with intermittent ignition.

Question: The resistance on the Hot Surface Ignitor reads 95.7 -- some of the thresholds I found online says that between 30 and 200 is acceptable -- others say anything over 75 is unacceptable. I'M SO CONFUSED!

It glows real nice and has no cracks but it doesn't always ignite. Maybe one out of 10 tries, on average. Could it still be bad even though it looks really nice? Here's what usually happens:

- Thermostat calls for heat
- Blower motor starts running
- After about 12 seconds small click, Hot Surface Ignitor (HSI) Starts to glow
- After about 15-20 more seconds, no click, just "pssssssss" gas sound for about 5-8 seconds but HSI powers down with before there is any ignition - one out of every 15 no-starts, the burners will light for a half second and shut right down with the HSI

The inducer motor stays running and the HSI repeats it's process 4 or 5 times and then if there's no start, the inducer motor shuts down and system goes dormant.

It looks like this:
 
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Old 11-22-21, 09:51 PM
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There are a boatload of those igniters. The price and quality are all over the place.
They are being phased out in many older furnaces for the round type of igniter.

York/Luxaire has igniter issues.
Two things.....
Try to find a Norton 271N ...... not a sub. Those run hot.
Make sure the burner is clean where the gas comes out and hits the HSI.
Sometimes you need to slide the HSI in or out a slight bit.
 
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Old 11-23-21, 10:07 AM
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I have had delayed/no ignition from some of the replacements. I've not had any of those issues with the Norton part. It seems to be getting harder to find the actual part.
 
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Old 11-26-21, 07:52 AM
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That PSI gauge is either grossly inaccurate or you were measuring a high pressure supply line somewhere else.
That’s not the proper gauge for measuring gas pressure.
You’ll have to find other means of checking gas pressure at the valve and manifold.
Take the jets out and make sure the hole is clear. Visual inspection isn’t going to work or tell you anything.
 
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Old 11-26-21, 03:56 PM
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This link will give you DIY instructions for a tool that would be much more accurate for gas measurement than the gauge you have. Build a manometer - YouTube
It's not as handy as the digital ones I use, but much less expensive.
 
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Old 11-26-21, 05:13 PM
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There will likely be small changes to ductwork, gas piping and flu locations.
Equipment is made as a puzzle piece. You have to cut out the return air opening, there will be a knockout type panel to cut on.
It also needs to be commissioned. Gas pressure set, airflow checked. Things like that.
The gas valve will need changed. Those style aren’t allowed anymore. Your local jurisdiction may also require permits to be pulled.
 
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Old 11-26-21, 05:24 PM
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Foolish me for offering the option of a DIY tool on a DIY site.
I made one long ago as a kid, and another this summer to educate my grandson. Cost was zero as I already had everything, and time spent was close to that. Oh well, it's the OP's choice and I really don't care.
 
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Old 11-22-21, 07:42 PM
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xxxxxxx
 
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Old 11-22-21, 08:14 PM
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Depends on the type of igniter.

That type is carbide - https://www.coorstek.com/english/ind...igniter-specs/

I don't think ohms are 100% reliable.

1992 furnace - really important to check the heat exchanger for cracks before buying parts.

 
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Old 11-22-21, 09:49 PM
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user 10 > Those numbers are even higher, so by the ohms standard, the HSI is good.

So, I guess the valve is going bad?

PS - the heat exchanger tests fine. Does a cracked heat exchanger cause intermittent ignitions?
 
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Old 11-22-21, 10:03 PM
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Thanks Pjmax.

Burners are clean as a whistle. I'll try to find the right HSI in the Norton if you think it'll make a difference.

Much appreciated.
 
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Old 11-23-21, 10:38 AM
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Thanks again Pj - just so I'm clear, is it possible for a HSI to appear fine (glows nicely, no visible cracks, resistance within thresholds etc) but not ignite correctly?

 
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Old 11-23-21, 03:33 PM
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What does "heat exchanger tests fine" mean? Has it been visually inspected for cracks.

A heat exchanger failure will not necessarily cause delayed ignition, but it needs to be checked before bothering to order parts.

The igniter ohm range depends on the model of the igniter and i do not believe it is 100% reliable as resistance changes as it gets hot.
 
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Old 11-23-21, 04:32 PM
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The exchanger was match/smoke tested this fall and it was sound.

But I am now considering preemptively replacing the unit entirely - its nearly 30 years old and much less efficient than today's furnaces. I'm having the PSE&G come by next week to give me a free estimate.

Regardless, its still imperative for me to keep this furnace going to keep my family warm, so I NEED to figure this out.

I don't know if this matters or not but the longer the furnace stays off, the harder it is to start. Ring a bell?

From your experience, could I just need a new HSI?



 
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Old 11-23-21, 05:38 PM
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An igniter heating to orange is not hot enough. You need it to almost get white hot.
 
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Old 11-24-21, 08:58 AM
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@Pjmax > I purchased and installed the new Norton 41-409 - Model 271M HSI and there is no change - the same problem is still happening. Again, the sequence of events is:

1) Thermostat calls for heat
2) Blower/inducer motor starts running
3) After about 12 seconds small click, Hot Surface Ignitor (HSI) Starts to glow
4) After about 15-20 more seconds, no click, just "pssssssss" sound for about 5-8 seconds
5) then an audible, louder click and simultaneously, the HSI powers down before there is any ignition - one out of every 15 no-starts, the burners will light for a half second after the click and shut right down with the HSI

When it does light, it lights simultaneously with the louder click.

I have come to believe that the "pssssssss" sound is not gas being released because I have hit the tube ends with a flame/torch and there is no ignition/lighting. I don't think the gas is being released until the louder click happens. so, I suppose that somehow, the timing sequence is quirked.

My theory is that until warm, for some reason,the HSI shutdowns simultaneously with the gas valve opening. I guess this is a gas valve issue and the only true fix would be to replace the valve?

Sound right?





 
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Old 11-25-21, 07:44 AM
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Bump. Anyone have a suggestion?

 
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Old 11-25-21, 08:52 AM
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What is incoming and manifold gas pressure?
Pull the burners and gas valve assembly. Pull the nozzles and clean them. Then reassemble. Also test and adjust gas pressure at this time.
 
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Old 11-25-21, 09:24 AM
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15-20 seconds is not very long for a 271N igniter. Is it actually glowing close to white hot ?
My York preheats for better than 30 seconds and it just gets hot enough.

On my burner the gas comes up thru slots in the burner tube. The location of the igniter was critical.
I could hear the pssssssss sound when it didn't light too. I thought I also smelled a bit of gas.

Newer control boards monitor igniter warmup time and ignition start and change the preheat time accordingly. My White Rodgers board has that feature. When you power down it's lost and has to cycle several times to relearn.
 
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Old 11-25-21, 09:47 AM
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Thanks guys for the responses. I'll get busy cleaning the gas lines and timing again the HSI and post my results.

Happy Thanksgiving to you and thank you SO much for sharing your expertise!

 
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Old 11-25-21, 10:22 AM
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Old 11-26-21, 06:39 AM
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@roughneck77 > disassembled much of the delivery piping leading up to the valve and everything was as clean as can be. Not even a drop of water or a crumb even in the sediment trap.

I've read a little about adjusting the pressure, I suppose it couldn't hurt but I don't have the right equipment to perform that task and I'm not experienced enough. I DO have a gauge that measures the delivery pressure before it enter the furnace, and it falls well within the acceptable margins.

The flames look right (to my novice eye) when it starts so I'm not sure if that is the correct route? I suppose I could give the adjuster a "customary" turn in the right direction as see if that makes a difference. I could always turn it back.

I believe it's clockwise to increase the pressure or counterclockwise to decrease the pressure -- how far should I turn it?

 
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Old 11-26-21, 06:50 AM
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DO NOT adjust the pressure without a gauge.
I did not mean pull the supply pipe apart, I meant pull the burner and clean the nozzles out.
If you measured supply pressure, what was it specifically. Gas pressure is measured in water column. Not PSI.
 
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Old 11-26-21, 06:50 AM
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@Pjmax > I timed it with a stop-watch to be precise, my estimates were a little off. It took 3 tries to light:

First try:
Ignitor glowed for 37 seconds when the "pssss" sound started. At 44 seconds that was a loud "click" and the ignitor shut down.

Secondt try:
Ignitor glowed for 43 seconds when the "pssss" sound started. At 49 seconds that was a loud "click" and the ignitor shut down.

Third try:
Ignitor glowed for 43 seconds when the "pssss" sound started. At 46 seconds that was a loud "click" and the the furnace started.

I've interchanged the HSI's to see if there's any difference in the timing but there isn't. I mat try to return the new one, not sure yet.

What's my next step?

THANKS to you guys, I really appreciate it!!

 
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Old 11-26-21, 07:09 AM
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roughneck77 said: DO NOT adjust the pressure without a gauge.
I did not mean pull the supply pipe apart, I meant pull the burner and clean the nozzles out.
If you measured supply pressure, what was it specifically. Gas pressure is measured in water column. Not PSI.


I used this PSI gauge below, it was just under 8 lbs which is consistent with every other time I've measured it in this house over the years.

The jets were clean as a whistle.

Anything else I could try?


 
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Old 11-26-21, 01:55 PM
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roughneck77 said:
That PSI gauge is either grossly inaccurate or you were measuring a high pressure supply line somewhere else.
Thatís not the proper gauge for measuring gas pressure.
Youíll have to find other means of checking gas pressure at the valve and manifold.
Take the jets out and make sure the hole is clear. Visual inspection isnít going to work or tell you anything.
I realize that's not the correct pressure gauge but it does show consistency. What should the PSI be? We used that same pressure gauge over-the-years in local friends houses and best I can remember, they all seem to be around 8 PSI, give-or-take? My memory is not good but that's how I remember it.

Tubes and valves are as clean as a whistle. Below is what they looked like. It seems my bi-annual cleaning/maintenance efforts actually paid off in that respect, anyway..

What should I do next?












**These pics depict the parts as they existed. I blew them all out with compressed air following but there was no blockage to speak of, none at all. I even tried to capture the INSIDE of the feeder rail / pipe to show that there is zero degradation, oxydation/rusting, gumming of debris build-up of any kind.



 
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Old 11-26-21, 02:08 PM
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The gas system doesn’t run at a measurable PSI scale. It runs at inches of water column. So the manifold will run around 3.5” WC for natural gas, or 0.12644552139573745 PSI. Your gauge will not even move at a 1/4 of a PSI. It’s simply the wrong scale, that gauge isn’t usable for the purpose.
I don’t know what you were measuring and adjusting but it wasn’t gas pressure with that device. That looks more like a leak down pressure test gauge to me.
 
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Old 11-26-21, 04:00 PM
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They are cheap enough, I wouldn’t worry about building one. Just buy a cheaper digital one, or an older style analog gauge.
 
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Old 11-26-21, 05:08 PM
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Thanks fellas.I appreciate the info. I have another question concerning replacing this furnace - because I don't know how any of this works:

Is there a chance that the new furnace I purchase will line right up as far as the flu, and ductwork?

Because if that's the case, I don't need to pay someone $2G's - in all my years of home ownership, I have really done all of my repairs myself but I figured installing a new furnace was out of my ability range. But if everything lines up, I can definitely do this.

My present furnace looks like the one pictured below and most of the new ones I'm looking at online appear to have the same setup. I have a good set of hands, quality tools and a strict desire learn and adhere to construction codes.

So, can I do this myself?




 
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Old 11-26-21, 05:26 PM
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It is a DIY site. But for accuracy and simplicity for the OP that has no heat, purchasing one is likely the easier option.
 
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Old 11-26-21, 05:31 PM
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roughneck77 said: There will likely be small changes to ductwork, gas piping and flu locations.
Equipment is made as a puzzle piece. You have to cut out the return air opening, there will be a knockout type panel to cut on.
It also needs to be commissioned. Gas pressure set, airflow checked. Things like that.
The gas valve will need changed. Those style arenít allowed anymore. Your local jurisdiction may also require permits to be pulled.
Thank you, friend. I'm confident cutting out the sheet metal, doing the gas piping and any flu work and the valves etc but I wouldn't even know where to start if I need to adjust the duct work. And yeah, I have no way of setting the pressure, so I guess this is why you don't hear very often of a DIY'er doing this job.



 
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Old 11-26-21, 05:39 PM
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fastback said :
Foolish me for offering the option of a DIY tool on a DIY site.
I made one long ago as a kid, and another this summer to educate my grandson. Cost was zero as I already had everything, and time spent was close to that. Oh well, it's the OP's choice and I really don't care.
No sir, I absolutely appreciate your input and I should have acknowledge you sooner, my bad. Thank you, sir. I watched the video and realized that I have all of the parts on-hand and absolutely plan on building this asap.

Much appreciated. Thanks again!

 
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Old 11-26-21, 05:53 PM
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Reviewing the posts and dates I didn't get the feeling that accuracy simplicity, or easiness was a concern. It seems that the latest turn to purchase a new one should handle all of that. While explaining what's needed for replacement you may wish to also explain how to determine if it needs a chimney liner as that is not a small price item. Or, keep it simple and let the installing company do that.
 
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Old 11-26-21, 06:20 PM
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This leads to a fork in the road. Will you investigate a new furnace or try to fix your current one?
Unless your current one has a compromised heat exchanger there’s no real reason to not diagnose it.
 
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Old 11-26-21, 06:39 PM
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Well, it's both for right now. Having a 30-year-old furnace, despite being well-kept and in excellent condition, brings with it a mindset that replacement-day is coming much sooner-than-later.

Cold weather is here and I need the furnace to work everyday from here-on-out or my family is cold.. While I'm trying to figure out what's wrong with this furnace, i'm also scheduling estimates for a total replacement and looking at units online.

If it's a matter of $10 bucks for a new flame sensor, this furnace lives on - but I'm not gonna spend $179 for a circuit board and another $155 for a new gas valve. That money is better spent going towards a new furnace.

Does this approach make sense and seem logical?

 
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Old 11-26-21, 07:07 PM
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Yes, but may involve also spending money on tools to diagnose it. Or a service call to determine whatís wrong.
 
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Old 11-26-21, 07:44 PM
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Makes sense to me. If I'm on a call in your situation I would diagnosis and give options. Certainly my costs would be higher than DIY costs. But if a simple fix isn't in the cards, the service call cost would be deducted from the replacement cost. I know that kind of policy isn't unusual. Regardless of your choice, Good Luck.
 
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Old 11-28-21, 08:52 PM
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Any updates?
 
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Old 11-30-21, 10:04 AM
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Any updates?
yes, thanks. The manifold pressure is 3.5 - exactly where it's supposed to be. I'm still having the same issue.

Because the start-up sequencing is not really consistent, I'm going to assume that it is a circuit board issue or possibly a gas valve issue.

Question: has anyone ever attempted to rebuild one of these valves? I have the old one, just wondering if it can be done - maybe it just needs a good cleaning-out like the carburetor on your snowblower?



 
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Old 11-30-21, 04:20 PM
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Gas valve is absolutely not serviceable. But whatís wrong with yours? Is it delivering proper output pressure when energized?
It doesnít sound like a board issue either.
 
 

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