Mighty Therm 325k High stack temp

Dick Carlson

If I get the manifold pressure anywhere near 4.0" W.C. my stack temp goes to 525 F. Is this normal for an atmospheric boiler?

Blackoakbob

is it really 4\"....

what kind of measuring stick are you using, a guage or liquid-filled manometer?
The reason I ask is a trusty old dial type gauge wasted a half day on a job because it just wasn't the right thing for the job. I was trying to set up a GP burner and it just wasn't right. I dug out my Bachrach "blue" manometer and foung the trouble right now. I had called the factory for assistance and the guy asked what I was using, when I told him he said " Throw that@#%& away!
Anyway, anything higher than the specified manifold pressure will increase your input and the stack temp. You should clock the meter to check the input and run a combustion analysis when your input is correct.
Best Regards,

Dick Carlson

I was using a digital manometer. I clocked the meter at 160k at a setting of 3 on the modulating valve and the stack was over 400 F. Manifold pressure was about 2.25" at that setting and my delta T was 20 degrees through the boiler with a 26-99.