Mod cons for dummies

Brad White

Modulating is the ability to change the firing rate "in flight" and is counter to "on-off" or "bang-bang" control as a single-stage boiler will do. It allows the output to match the load if you manage it correctly and saves you from the only option conventional boilers have: Shutting off.

Condensing is just that, extracting the latent heat from flue gasses. Instead of 350 degree F flue gas you exit at 130 degrees or less. The difference goes into the house.

A little more to it (such as how the modulating can be controlled to track and optimize water temperatures (i.e. Outdoor reset) coming and going.... but that is another thread. Or Rope.

Brad

Dave_4

Direct me, please

Either to a web source for a discussion all about modulating condensing boilers, or if you are so inclined, tell me right here.

Like for starters, what is meant by "modulating." And what about "condensing."

I'm a GC, and also an engineer, and I know nothing about this stuff, but am curious.

Modulating? Hmmmmm. Let's see. Either the burn rate can be modulated, or something else. What's it do for heating?

Condensing? If I recall from freshman year thermodynamics, heat can be recovered in the condensing cycle. So, do we make use of that?

I'm anxious to hear all about it.

jp_2

also,

most of the time you can heat the house without 180F water, say 130-140F. this reduces losses throughout the entire system. higher water temps equal higher engery needs.

mod= heating the water only as hot as is needed!

McKern

This might help...

http://boilerbuff.com/forum/index.php?topic=93.0