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Heat Exchanger

Started by Brewster, November 14, 2010, 08:54:18 AM

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Brewster

I have a HeatMore outside Boiler and the heat exchanger in my furnace is piped down from 3/4" to 5/8". Thinking of replacing with a 3/4" pipe transfer unit for better recovery time and wanted to know thoughts ?
20"x20"x10" Forced Air unit and the company that installed it placed a 22"x16"x10" which has me thinking they had some old stock and cut my throat. Beside from the fact its the wrong size they didnt even fix it so there isn't any blow bye the exchanger.
Hard to find good help no matter where you live!

Besides from the obvious want to get input on flow on pipe size. The system is hard piped 1-1/2 and 2" to and from the boiler. Running temp is 185 to the coil, my efficiency problem is obviously the exchanger.
Thanks for any and al help,
Brew

snowstorm

mine is 1" pex insulated from the boiler to the house then i put radiant in the floor. that works real well quiet no dust floors are 80 degrees

Holmes

Welcome to the FF Brewster.  1.5" pipe will deliver plenty of btu's to your exchanger.185* is the right temp.  First I would get rid of all blow by.  . If the exchanger is supposed to deliver over 45,000 btu it should be piped 1" over 85,000 btu it should be piped 1 1/4 ", a larger  pump head pressure can push more btus thru a smaller pipe. That would require changing the pump. Holmes
Think like a farmer.

red oaks lumber

welcome,
why are the lines running to and from the house so large? your biggest volume of water flow is only as large as your smallest pipe(5/8) sounds like to me you were sold a hack job. if they just installed it this fall i'd complain if not, replace the heat ex. for the proper fit also make sure the pipe is 3/4 .
what rate of flow is your circulating pump? to fast, not enough heat is taken off the water, to slow to much heat removed making you stove work harder reheating cooler water.  good luck
the experts think i do things wrong
over 18 million b.f. processed and 7341 happy customers i disagree

doctorb

You've identified two potential problems.  To just change just the pipe size, since you'd have to take the system apart anyway, without changing out the heat exchanger would seem like only a partial fix.  It's hard to know if the efficiency loss is from decreased flow volume (pipe diameter issues) or poor exchange of heat to the FHA system (too much blow by), or both.  When you do correct it I would install thermometers on both the inflow and outflow lines to the heat exchanger.  The gradient of these two temps is a good way to visualize the amount of heat energy extracted from your system.

Is there a way to measure how much blow by occurrs?  If you could block up that unnecessary, unheated, cool air diluted air flow, even temporarily, you might be able to get an idea of whether it's the decrease in pipe diameter or the poor fit of the heat exchanger that's causing your heat loss.

Are you currently concerned that your outdoor furnace is just working too hard to keep up (burning too much wood), or is the system just not able to keep up with demand for heat and you are cold inside?  Doctorb
My father once said, "This is my son who wanted to grow up and become a doctor.  So far, he's only become a doctor."

ronwood

How well is the lines coming into the house insulated? Poorly insulated lines in the ground can result in a large heat loss.

Ron
Sawing part time mostly urban logs -St. Louis/Warrenton, Mo.
LT40HG25 Woodmizer Sawmill
LX885 New Holland Skidsteer

superwd6

Make sure all the air blows through the coil you have and there isn't air trapped in the coil. The coil doesn't have to fit the duct size for size but ALL air should blow through it

thecfarm

Brewster,welcome to the forum.I had a Heatmor since 2007.Best thing I ever bought.I had to look up the BTU on my heat exchangers and thought I might just as well post a picture.I have one like this in my duct work too,but with a tight fit.Mine are 86,000 18X16X6. Mine are plumbed one inch.No idea if this is right or not,but we're always warm. I had someone installed mine.


Model 6020-20hp Manual Thomas bandsaw,TC40A 4wd 40 hp New Holland tractor, 450 Norse Winch, Heatmor 400 OWB,YCC 1978-79

Brewster

Hey Guys, Thanks for all the replies, welcomes, and ideas on trouble shot this problem!

Its supply line in and out are 1" HePex and then reduces out with copper. I don't know what my pump is pushing due to it's the back of the Boiler House outside and its dark and snowing right now. Will follow-up with more information and pictures on that later. Along with pictures of my system with reducers and exchanger.

My lines are well insulated and fine. Also my Boiler is in great condition and on a regular maintenance program. Im sure the problem all lays within the furnace and the installation of the coil.

Appreciate the help,
Brew

woodmills1

I would also ask why your 1" pex is reduced to 3/4 copper

your 5/8 exchanger only allows 25/64ths of the flow of one inch

the 3/4 flows 9/16ths of the one inch

I would change them both


James Mills,Lovely wife,collect old tools,vacuuming fool,36 bdft/hr,oak paper cutter,ebonic yooper rapper nauga seller, Blue Ox? its not fast, 2 cat family, LT70,edger, 375 bd ft/hr, we like Bob,free heat,no oil 12 years,big splitter, baked stuffed lobster, still cuttin the logs dere IAM

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