CO and a Smith boiler

Steve McCarthy

Today I replaced a badly corroded vent on a Smith boiler. The owner says it is about 8 yrs. old. Model number is GV100-W-5-HSI. It is sidewall vented and before today was vented with 7' of single wall galvanized pipe. When I first looked at it the pipe was badly corroded at all the joints and there was a pile of corrosion at the breech. Under the front cover was more corrosion below the draft inducer and I was concerned that the condensate had gotten to the cast Iron. When I pulled the draft inducer, I found that the condensate had been able to escape down through the draft inducer and has done no damage to the boiler. The damper on top of the draft inducer was corroded and I worked on it to clean out the rust and deposits and it now works nicely. I remounted the inducer with new sealant, removed, cleaned and replaced the burners, cleaned the orifices, checked the passage ways between all the sections, fired it up, checked the firing rate, right on, measured CO at the outlet and got 475 PPM. I lowered the firing rate and the CO went Higher, a lot higher!!!!!! off the scale of my Monoxor 11. Raised the firing rate to 100K and again got 475 PPM. The new vent connector is sealed and all the garbage is going outside but... 475 is way too much. Help.
I am suspicious of the little damper above the draft inducer. It does not seem to open very far. Suggestions???

Steve

Mark Hunt

What other readings did you take?


Mark H

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Jim Davis

Inducer is probably pulling too much air which is why the CO readings got even worse when you turned down the gas pressure. Really need to do a O2 & Temperature test also to verify the problem. I would bet if you added a little more gas the CO would drop even farther, but without other information this is not recommended yet. The corrosion is caused by the inducer motor shutting off too soon at the end of the burner cycle. Must be recontrolled to make inducer run for at least 2-3 minutes after burners are off.

Tony_8

Smith GV

LOTS of problems with that unit. Make sure that it is set on a flat, solid surface also. If it's on blocks with the bottom open in the center it won't burn properly.

Jed_2

That Boiler Requires

AL29-4C gasketed SS vent pipe, probably with a condensate drain tee. Galvanized smoke pipe does not meet Standard 1738. It's a power vented boiler, basicly.

Jed

kevin coppinger_4

You don't need....

the condensate tee....only if you run the vent up a chimney....kpc

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