Best Of

I think we're pretty much on the same page, @jesmed1 . Different terminology, perhaps.

In reality, it really doesn't matter that much — until the numbers get baked into regulations or specifications. Then it starts to matter… a lot.

I just want to express my gratitude to the HeatingHelp community for stepping up and helping me preserve some of my favorite hydronic books and relics.
And a special thanks to Erin who went above and beyond helping me with this. Without her efforts, none of this happens. You’re the best. ☘️☘️☘️

I totally agree that the combustion measurements taken by the equipment used in the field are dry gas measurements, and make no allowance for the water vapour in the combustion gas.

I was — and remain — much more concerned about the problem which is wide spread that the difference in higher heating value and lower heating value of the fuels is not understood — even when people are aware of it — and that recovery of that latent heat is the key to the high apparent efficiencies of condensing boilers.

From my point of view I take any efficiency number with a very large "oh really?" attitude — just as I take things like horsepower ratings or other power output ratings. Provided that various devices are rated using exactly the same technology and procedures, those ratings can be of value as a comparison — but nothing much more than that.

Heating systems are particularly problematic, of course, since overall efficiency of the complete system is hard to define, never mind measure. It's a lot easier with power machinery — as an ME, you would know that!

Good morning,

Are you saying this system worked prior to the completion of the new work? System pictures may help. Any chance the wiring to the Taco was jostled during the add on work? Theres a plastic connector on the Taco E that if manhandled may become loose. This loose connection may give you the scenario you've described. Lack of circulation in a hot water system can cause steaming issues which will add air to an other wise air free system. But it can also be created by a piping issue.

@Resipsa88, I've merged your duplicate discussions into one here to prevent confusion. Thanks.

cut the intake pipe under the deck, put in a 45 to extend it farther away from the exhaust

Download the installation manual for venting clearances. The exhaust may be too close to the building or windows ?

has a combustion analysis been done.

Has the tech contacted tech support while on site?