To obtain the high amount of condensing!

brfaul

What combustion reading should you have to obtain the highest amount of condensing in the boiler? Does altitude have anything to do with this? Does high O2 readings hurt the combustion efficiency? Where can I find "real" information?

Gordy

Condensing at its finest comes from low return water temps.

If you look at efficiency ratings on numerous mod/con brands they usually boast higher than advertised efficiencies at low return temps. upper 80 to low 90s.

Obviously improper combustion deveating from factory recommendations will effect efficiency.

Robert O'Brien

Excess air increases stack temps,operating at the lower end of the allowed O2 range (Or upper end of CO2 range) will increase efficiency slightly

Zman

Higher CO2 raises the temp that condensation occurs. As Robert said if you tune towards that end of the range you gain some efficiency (assuming you are running low enough temps to take advantage ).
Altitude lowers the point of condensation decreasing it.
This is a good read.
http://www.fcxalaska.com/PDFs/AshraeCondensingTechnology.pdf
Carl

icesailor

I didn't know that (according to the PDF) if you have a 20 degree Delta T from 180 degrees to 160 degrees, through a fan coil, you have the same BTU output through the fan coil as you do with a 20 degree Delta T from 140 degrees to 120 degrees.

Taking an average, is it true that the same amount of heated air with an average of 170 degree output air is the same as 130 degree output air?

Why is hot water baseboard rated at lower outputs (need more installed radiation) than higher temperature BTU inlets?

If I have a building that is pumping 180 degree water, and heats fine, and I turn the water temperature down to 140 degrees and it gets cold, then I turn it back to 180, it gets hot again. That is contrary to what is said in the PDF.

Is someone shilling facts for someone?

An inquiring mind is wondering.

Zman

Ice,
The section is called Fan Coil sizing.
Notice the lower temp one has twice the surface area?
Carl

icesailor

Zman said:

Ice,
The section is called Fan Coil sizing.
Notice the lower temp one has twice the surface area?
Carl

That is not the conclusion that some rookie homeowner DIY will come to. And probably over 75% of all PVC installations aren't done according to the manufacturers UL listing requirements when it comes to preparing pipe and fittings for solvent welding.

Do YOU chamfer the end of the pipe before insertion?

Just because you have purple cleaner running off the end of the insertion, doesn't mean you prepared the pipe and fitting properly. If you can see the manufacturers printed lettering on the pipe, clearly with no change in appearance, go into the socket, it wasn't prepared properly. Therefore, it doesn't pass the UL listing requirement.

Zman

Whoa!
It is just a general, informative presentation to help educate folks on condensing technology. It is a not a "how to" or design manual. I happen to think it is quite well done. You are welcome to differ.
I think the rest of your rant belongs in that ridiculously circular thread about PVC venting. You can leave me out of that one.
Having trouble filling the hours, Chris?
Carl

Jean-David Beyer

"Just because you have purple cleaner running off the end of the insertion, doesn't mean you prepared the pipe and fitting properly. "

I'll say. My former contractor, who installed my mod-con, had purple stuff on all the PVC joints, but forgot to apply the glue in some of them. The condensate that formed ran out a couple of joints, and flooded the control electronics in the boiler. It took over a week for the new contractor to find the source of the water (no problem finding where the water ended up) because the PVC had been covered with a thin layer of black foam insulation (no reason for that) that hid the condensate running down the outside of the pipe.

There is a cure for stupid, but it requires finding a new contractor and paying him to do the job right. (But he did not chamfer the ends.)

Zman

Well I guess this one has been successfully highjacked....

icesailor

Zman said:

Well I guess this one has been successfully highjacked....

How is that?

All I said was that most of the PVC venting I saw wasn't welded together properly. Then, someone agreed with me and wrote his related story.

You should see plumbing. At one time, you were supposed to "prime/clean" the pipe and fitting, wipe out the solvent cleaner, and them place the solvent weld cement on both make and female ends. Now, I've seen "Experts" slather purple cleaner all over the pipe and fitting, immediately slather cement all over the wet solvent cleaner, and jamb the un-chamfered pipe into the socket. Where the un-chamfered edge will work like a new windshield wiper on a car windshield in a rain storm.

When I did woodworking, I used metal scrapers to absolutely remove any high spots before finishing. You held the scraper at right angles to the work and scraped. Any high material was scrapped off. When the edge became rounded, it wouldn't cut. I would have to run it in a jig over a perfectly flat stone to get it back. Like a paint scraper.

If you see the writing on the pipe, unaltered and going into the fitting socket, it wasn't cleaned properly. And I'm talking ANY kind of PVC.

Zman

Ice,
You make an excellent and informative point.
It just has nothing to do with the subject.
Why not start your own post?
Carl