Identifying Issues at Back of Boiler

TorontoMike

Our 90-year old home is radiant heated by way of a 13-year old Slant Fin GG 75 HXPED boiler. Last year we had our annual boiler inspection and the service provider (before replacing all the metal panels around the  unit) had me look from behind and pointed towards the back of the unit while it was operating to what seemed to be a seam that the flames of the unit had a slight glow to while it was turned on. He said it showed a normal wearing away of what he called a back gasket(??)... but is this not just a seam in a back assembly jacket (looked at Slant Fin specs but can't see such an identifier) and is it not normal to see a bit of illumination come through such a seam anyway? He said that the unit was safe for at least another year, but we could be looking at having to get a new unit soon re: possible co2 leaks. He claimed that the replacement of what he was calling a gasket would be a couple grand $$$, so it was more worth while to replace the entire unit as everything else would be wearing away over time. Our unit has shown no other issues and we were hoping to get at least another 2-4 years out of this before a costly replacement has to be done. Do you think he was raising a legitimate safety concern on his part or more of a scare tactic sales push to get us to buy a new unit through his company now? I ask because this week he will be coming in for this years inspection and I want to be able to address what he may be claiming with a more informed background than I currently have.

STEVEusaPA

Without pictures it's hard to understand to what you may be referring. Make/Model #?
You shouldn't see any fire or glow anywhere unless looking through an inspection door. If you do, it should be repaired/replaced. Don't know why anyone would think it's good for another year before it needed to be addressed. I'll assume he meant CO (Carbon Monoxide) and not CO2 (Carbon Dioxide).
A combustion test should've been performed as well as an ambient air Carbon Monoxide test. The latter is very important because if products of combustion (CO) are leaking into the living space, you have a very serious, dangerous situation.

TorontoMike

Yes, I meant CO. Since his comment from last year I got us an extra CO detector for the basement - 2 there and one on each floor above.

Mentioned the model of Slant Fin above. Slant Fin GG 75 HXPED.

I'll google around to get a better understanding in how to describe the issue - I thought before CO emissions were more of a venting through the chimney getting blocked issue...what he mentioned last year has me confused...

Thanks for the reply so far...will return to this tomorrow...

EBEBRATT-Ed

If this is the right boiler the boiler block sits on the steel base that contains the gas burners. You would have to take off the jacket to see what is going on. If the steel base it sits on is in good shape the only thing I can think of is maybe a small gap between the sections and the steel base. A bit of high temp silicone from HD get the high temp stuff sold in the aisle where the wood stoves are.

The gasket he speaks about is high temp rope #25 on the parts list. If the base & the sections are in good shape their is no need to replace the boiler

TorontoMike

"The gasket he speaks about is high temp rope #25 on the parts list. If the base & the sections are in good shape their is no need to replace the boiler"

Interesting. Thanks for the info.

EdTheHeaterMan

Here is the picture form the parts list and i have indicated with a red arrow where you indicated the flame glow was visible. Would you say the glow was coming from the place where the gasket (#25) may have fallen out or is the actual fire box metal (#8) below the arrow glowing cherry red?

Replacing that gasket is no easy task. The way I have made that repair is with a sort piece of that gasket rope material and furnace cement. Unwind the rope and coat it with furnace cement then wind it back up loosely, then stuff it in the seam the best you can with a narrow screwdriver or probe. Follow that with a liberal coat of furnace cement to hold things in place until the cement cures. The cement will dry out and crack away from the metal over a few days but you can add another coat of cement to seal the crack.

If the metal box (#8) is the part that is glowing, then you need new insulation material #8a and #8b replaced on the inside of the fire box.

Hope this helps.

TorontoMike

Thanks Edward for all this information...

Actually the guy just called - he's coming over and I'll try to get some pics...

TorontoMike

TorontoMike

So I squeezed behind the unit (tight squeeze) to snap this with the metal back panel taken off, so this is a view of the unit facing the back wall. Not a great photo but the lighter line appears to be something like a rope gasket towards the back.... maybe in the seams in section 9 (above the red line) of Edward Young's post above...so I guess it's the back of the heat exchanger itself? Tech shone his flashlight from the open front towards the back...he pointed out that sections of it seem a bit lighter in some parts than in others...said it should be fine for this heating season but it will only wear away more in the future which may lead to a CO leak.

EBEBRATT-Ed

@TorontoMike

the rope looks fine i think your chasing a ghost that doesn't exist. Boiler sections don't always look the same.

TorontoMike

Hope you're right... Just monitoring with CO detectors (the cheaper way to go) is the only action we plan on taking for now.