Coalpail.com Forum

Hi everyone, great forum you have here! I just picked up my new k8 boiler last week and am looking to complete the install over the next week or so. I plan to tie into my existing ductwork with a water/air heat exchanger and use the existing fuel oil furnace blower to distribute heat as the house is quite large (4500+ sq feet) and radiant is not in the budget for most of the house. My first stumbling block is how to size the w/a exchanger. Oil furnace is 180k BTU input, and heats the house very well, but to the tune of over $900/month in fuel, just to maintain 64 degrees. Would a 180k BTU exchanger be a good ballpark? aside from a circulator pump and expansion tank, most everything else can be purchased locally I believe. I would like to order from pexuniverse asap so I can complete the install between friday of this week and next wednesday. I have been reading here for the past week or so and gained a lot of insight, thanks again for a great forum! Any help on the heat exchanger issue would be greatly appreciated!
greg

Welcome.

What size is the duct work where you intend to mount the water to air heat exchanger?

Will the Keystoker be installed in your basement?

Some good reading about other w/a heat exchanger installs on the forum: Water to Air Heat Exchanger Questions

the plentum coming out of the original furnace is 24 inches square. the boiler will be installed in the basement directly next to the existing fuel oil furnace. working on uploading some pictures of that room now.

Sorry, no go on the pics till I get home from work on friday. Apparently my smart phone is smarter than I. Sigh.

a 24"x24 plenum would accomodate a 22x22" exchanger...
one that size COULD deliver over 200,000. btu...not that you would ever need it
...20x20 may be fine as well....but personally I would go with the larger (imo)
...welcome to the forum...!

Doesn't matter how big your duct work is. you can have transitons fabricated to accomodate whatever size heat echanger you need. Like this.

coalkirk wrote:Doesn't matter how big your duct work is. you can have transitons fabricated to accomodate whatever size heat echanger you need.

heat exchanger.jpg

Like this.

Nice install. I was thinking that if he could get away without serious ductwork modifications that would be preferable. Any idea what the circulator requirements are for one of these heat exchangers? Size of the heat exchanger is just part of the puzzle.

Taco 008

Carbon12 wrote:Taco 008

Ok. How did you come up with that?

Ha! Easy! After a long discussion with the heating system design engineer I used to work with he just said Taco 008. He didn't like any of my other choices. My system is similar to what is proposed.

Obviously, without knowing specifics of the proposed system, recommending a circulator would be a shot in the dark. But the 008 would PROBABLY work adequately. One zone, little head. Pressure drop across the coil is unknown variable.

Rob R. wrote:

coalkirk wrote:Doesn't matter how big your duct work is. you can have transitons fabricated to accomodate whatever size heat echanger you need.

The attachment heat exchanger.jpg is no longer available

Like this.

Nice install. I was thinking that if he could get away without serious ductwork modifications that would be preferable. Any idea what the circulator requirements are for one of these heat exchangers? Size of the heat exchanger is just part of the puzzle.

Mine is a Grundfos 3 speed. Chosen very unscientifically I'm afraid but worked out fine. I've added an led to all my pumps for a visual cue that it is powered.

X2 On the 3 speed...your comfortable house will thank you.
And no calculations and then still maybe get it wrong.

Wherever you order the coil from should be able to tell you with some certainty what circulator pump you need.