Monitor only at 90% on combustion analyzer

Luke Lefever

I installed an MZ25C in my personal residence last fall and have been saving a huge amount of money compared to the antiquated system that was in there. I put the combustion analyzer in the vent and it came back at about 90.1%. I do realize that the AFUE ratings are figured in laboratory conditions that very few installations will ever duplicate. The CO readings were a little higher than I would have expected 30+ ppm- I guess my question is can I adjust the gas pressure to get better efficiency without harming reliability? I don't want to open the can of worms that was going hot and heavy about efficiency and modifying from factory settings. Anyway, is it too much to ask that this thing would be more efficient?

Water temps at test time.... supply to radiation 133, return from radiation 110. Primary loop running about 140. Ergomax not calling for domestic heating need.

We are on track to spend in one heating season, what the previous owner spent for one month, and our gas is 50% more expensive than last year!!!

Any thoughts? Thanks, Luke

[Deleted User]

AFUE

AFUE is different than combustion efficiency. AFUE takes into account how much you save during the OFF cycle due to things such as intermittant ignition, vent dampers (on other boilers), insulation, and outside air supply. These things won't change your combustion efficiency, but will effect the AFUE.

Noel

Unknown

You ain't gonna

get much better than what you got. If it ain't broke don't fix it.

eddie grierson_3

I wonder what the return water temperature they were working when thet got there AFUE?

leo g_30

50% higher

and your cost is gonna be compared to one month last year? and your looking for more????? LOL!!!!

man, be happy, it seems to me that that unit is doing exactly what they claim!

leo g

Unknown

I think they tested

with 120 degree return water temperature. The MZ people would know, by the way I have not seen him around lately. Matt Connelly I believe was the name??? Getting old I may have wrong name.

kf_2

Analyser

By the way, a combustion analyser will not accurately produce ratings higher than 90%. The actual amount of condensation has to be measured for a certain period of time to properly calculate condensing efficiencies.


kf