IBC boiler SL20-115G2 delayed ignition

electron

Hi everyone.
I just had a brand new IBC SL20-115 G2 boiler installed recently. Ever since the installation, I noticed that during ignition, the boiler would make a "thump" sound. From reading, this seem to be delayed ignition problem.
The installer did some troubleshooting with the IBC tech on the phone, they measured the gas pressure and it was fine, and then they decided to replace the burner assembly.
However, problem was not solved, the noticeable "thump" noise is still there.
Anyone has any experience with this issue for this particular boiler? How did you fix it?

Thank you for reading

kcopp

Is this LP or Natural gas? has this done this from the start?

electron

Hi Kcopp,
This is natural gas model and that it is doing it from the start.

kcopp

I have never had that happen before. Check the igniter to see that it is in the opening and tight. Check your connections.
How loud is the "thump"?

Abracadabra

How's the draft? Combustion analysis been done?

kcopp

That's a great question., I presumed that a combustion analysis was done on a new install.... What did they get for numbers?

electron

Thanks you all for trying to help.
Here is a video showing the "thump" noise.

https://youtu.be/IsnrnX3sSs0
I am not sure if an combustion analysis was done...i hope it is.
How do i check if the ignitor is in the opening?

electron

The boiler has so far logged 5 ignition errors and 8 ignition trials since it was installed 3 month ago

Abracadabra

Does that boiler have spark or HSI ignition? If spark, make sure the gap is correct.

kcopp

Spark... Still like to know what the combustion test #'s are.
Ask the installer.

electron

I believe the combustion analysis was not done.
Can someone confirm that this noise is not normal?

kcopp

It is lighting off a bit hard yes. It is not as smooth as I would like to see/ hear. Not "normal" but not super unusual.

kcopp

Did you ever find out if the installer did a combustion test?

electron

I think i better get someone to verify just in case.

rick in Alaska

I was having problems with the Triangle Tube boiler doing that also. It took quite a while for someone to figure it out. Turns out the gasket the ignitor goes through was too close to the ignitor and was "shorting"it out. They now have a new gasket they are using that has a tapered opening at the bottom that has fixed the problem. If yours is the same type of heat exchanger, you can pull the top off and taper the gasket back at the bottom just a bit to get more clearance around the tip of the ignitor.
Rick

Aaron_in_Maine

I had a NTI fire tube boiler doing the the same thing. It was a warped igniter. The had boiler been in service for five years or so. Replaced igniter and all is good. Strange that it did it right out of the box.

electron

Hi Rick in Alaska,
Thank you for your input.
Sorry, I dont quiet get how the tapered gasket work. Can you please explain more detail on what I need to do?

Hi Aaron in Maine,
Yes, I am trying to figure out why a new boiler would do this.

rick in Alaska

Not sure about your boiler, but the Triangle Tube boiler has a gasket on the top plate that the burner mounts to that is about 5/8" thick or so. It is under the top plate. The ignitor goes through this gasket. The gasket just has a straight through hole cut in it for the ignitor to go through. In order to fix the problem, you need to have the bottom of the hole tapered out away from the ignitor tip. You would need to take the top plate off to access the gasket, and then carefully carve away just a little bit of the gasket, but only on the bottom section. Leave the gasket intact where it meets the top plate.
I just looked at the boiler and found the gasket is part number 140 in the manual.
Rick

electron

Hi Rick,
Do you mean the two rods from the ignitor are touching the refractory causing it to be shorted?

I had someone came in to do the combustion analysis.
On High fire
O2 = 4.3%
CO = 36ppm
Eff = 88.5%
CO2 = 9.4%
T-Stk = 160F

kcopp

were those number at Low fire or High fire?

Jamie Hall

electron said:

Hi Rick,
Do you mean the two rods from the ignitor are touching the refractory causing it to be shorted?

I don't think that that's quite what @rick in Alaska meant -- although I can't be sure, never having seen it. I'd bet that what it might be is that the combustible mixture can't get at the ignitor quickly unless there is a bit more space around it.

rick in Alaska

From what I understood, the ignitor will arc to the refractory. Not sure why, but that is how I understood it. After modifying the refractory, there have been no more delayed ignition problems on this job.
Rick

electron

Hi Kcopp,
Those number are on high fire.

Hi Rick,
Did that boiler you worked on came with this issue since new?

rick in Alaska

Yes it did. Triangle tube has now sent a different refractory (or so I was told by my rep) that has been modified. It was also kind of sporadic as to when it would mis-fire. But, the homeowner sure noticed it. Says it was like a cannon going off.
Rick

electron

My Ibc boiler would "thump" everytime it ignites.
Ibc has referred a contractor who has replaced the ignitor and did the combustion analysis and made adjustment. Initially thought that has fixed it. However, it seem the thump is still there. Also, i just realized that if I open the cover and look through the sighting glass while it ignites, I can feel there is air/gas blowing out somewhere (from the micro explosion?) I will try to get IBC to send a representative out to look at it. Has requested previously but they wouldnt. After 3 contractors and many hundreds dollars, I think I need to get them to come out. I cant believe a brand new boiler would have problem like this.

electron

Hi Rick,
Does the ignitor from the Triangle tube also look like this?


I suppose it's the other metal rod touching the refractory?

kcopp

Where you out of?

rick in Alaska

That is the same one. I don't think the rod touches the refractory, but I get the impression that it shorts out to it. Not sure how it can do that without going to the ground rod, but that is what I understand is what is happening. The trick is to get a little more clearance from the rod.
Rick

electron

Sorry, can I ask for a little clarification. So we make the refractory thinner from the bottom, not making the refractory hole for the ignitor bigger. Correct?

HVACNUT

The distributor who sold you or contractor the boiler should be able to provide you with the number for a regional rep. to meet with a reputable technician at the job site. The tech MUST have a digital combustion analyzer, manometer and true RMS multimeter.
Sounds like a simple throttle adjustment on the gas valve, but after purchasing their product for bucu deneros, you deserve to have the Rep. come out to the job.
Good luck.

HVACNUT

DO NOT ALTER THE REFRACTORY OR ANY PART OF THE BOILER.
YOU'LL VOID THE WARRANTY.

electron

Is there a way to limit the firing rate?

HVACNUT

Not familiar with that brand. Modulating? If there's an outdoor reset you can lower your design day temp. If DD is 10 degrees at 180, lower DD to -10 and she'll run at a lower rate throughout the band width.

aircooled81

I think you should have a fairley high amount of sparks per second, enough that the ignitor will look like a constant arc...
When the first stage for ignition takes place, what does the ignitor look like through the sight glass.
Is it sparking once a second, twice a second?
Fenwal posts the sparks per second on their website, for instance a 35-60 could spark 25/30 50/60 sparks per second.

Could be the ignitor is not operating like it should, gas builds up to high of a volume before combustion takes place.

kcopp

Any updates?

electron

Thanks everyone for the input.
IBC had an representative out, and the problem is fixed.
I believe the angle of the ignitor was adjusted to spark closer to the burner.

evolvebg

Hi electron, I had the same problem with my G2. I'd love to contact you directly and discuss it if you are open to it. my email is jpavia@evolvebg.net. thanks!

MauriceC

I'm having the same issue, how did he adjust igniter to get closer?