Outdoor Wood Furnace Info

All-Purpose OWF Discussions => Plumbing => Topic started by: kc on November 28, 2012, 09:26:41 PM

Title: heat exchanger install opinions
Post by: kc on November 28, 2012, 09:26:41 PM
Well I picked up my mountain man 505 over the weekend and she is sitting pretty on her pad waiting to be hooked up and fired up.   I am installing my underground pex this weekend and on to hooking up the hot water and furnace there after.   But I still need to finalize my furnace heat exchanger selection.   From what I gather the most straight forward place to install would be above my existing Ruud furnace and below the A-coil on the AC (see picture).   The duct work there is 20x20x12 so there is plenty of room for a shelf and a slide-in install.  But my brother-in-law who helped me set the stove on the pad and does sheet metal work was recommending I install the HE on the return side.   The return duct is approximately 12x23 and he offered to rework the duct making transitions to accomodate a larger HE.   Also my filter is at the base of the return so if we install on the return side that would place the HE before the filter and when I pointed that out he said we could move it.   What do you guys think?   Is it worth the trouble to rework the return side or go with the simpler slide-in route between the furnace and A-coil?   Thanks again for the infinite wisdom that flows from you guys on this site.   It is really a good feeling to be able to figure this stuff out and do most (maybe all) of the install myself...

kc

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Title: Re: heat exchanger install opinions
Post by: RSI on November 29, 2012, 06:24:16 PM
I would put a 20x19 under the A coil.
Title: Re: heat exchanger install opinions
Post by: kc on November 29, 2012, 06:43:06 PM
RSI,

The dimensions I stated above are a tad off.  The width actually measures 20.5 on the inside so if the heat exchanger is truly 20" wide it should hold it.  Are the dimensions on an HE usually a little wider than stated?   One the other hand 19" wide should work too...

kc
Title: Re: heat exchanger install opinions
Post by: RSI on November 29, 2012, 08:34:25 PM
The measurements are just the finned area. A 20" wide is about 20-1/4" overall. The other direction there is an inch lip at each end unless you get the type with the flat plate at the manifold end.
Title: Re: heat exchanger install opinions
Post by: JMA on December 13, 2012, 05:01:27 PM
 :oBe carefull! It looks like you have a gas furnace. If you place the HX on the return side, it can trip the temperature sensitive gas regulator and then it's trash. If you have oil or electric, forget what I said and put it where you want.
Title: Re: heat exchanger install opinions
Post by: oldchenowth on December 18, 2012, 05:33:36 AM
I had no choice but to put mine on the return side.  Short ceiling and no room above or below a coil.  Mine is before the furnace filter, so my plenum is a little larger to put a filter above my HX, and we only have one return vent for the whole house (old farm) so I filter there also to keep the fins clean of dust.  Propane still works when the OWB is not fired up, so I cannot totally agree with trashing the furnace doing it this way.  That said, it is about a 7 year old 85% + furnace, so maybe it is not as touchy as a newer one.  All I know is the wife keeps the house at a sweltering 77 F all the time.
Title: Re: heat exchanger install opinions
Post by: baldwin racing on December 18, 2012, 02:42:16 PM
Well I picked up my mountain man 505 over the weekend and she is sitting pretty on her pad waiting to be hooked up and fired up.   I am installing my underground pex this weekend and on to hooking up the hot water and furnace there after.   But I still need to finalize my furnace heat exchanger selection.   From what I gather the most straight forward place to install would be above my existing Ruud furnace and below the A-coil on the AC (see picture).   The duct work there is 20x20x12 so there is plenty of room for a shelf and a slide-in install.  But my brother-in-law who helped me set the stove on the pad and does sheet metal work was recommending I install the HE on the return side.   The return duct is approximately 12x23 and he offered to rework the duct making transitions to accomodate a larger HE.   Also my filter is at the base of the return so if we install on the return side that would place the HE before the filter and when I pointed that out he said we could move it.   What do you guys think?   Is it worth the trouble to rework the return side or go with the simpler slide-in route between the furnace and A-coil?   Thanks again for the infinite wisdom that flows from you guys on this site.   It is really a good feeling to be able to figure this stuff out and do most (maybe all) of the install myself...

kc

i would go under the a coil on heat side and be done here is a pic of mine...I dont have ac but you get idea......my buddy does duct work and made this for me for $60 new heat plentium due to old farm house and low basement we made to fit....on hot side.....that way you do not mess with air filter stuff
2nd pic is with the exchanger installed and pipeing hooked up.....on right the valve there is were i have the automatic filler i have pressurised set up.....(not hooked up in pic) or before i had just water line there hooked up  when i need to add water i could in my old outdoor boiler....
kelly

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Title: Re: heat exchanger install opinions
Post by: kc on December 18, 2012, 09:22:47 PM
Thanks for the feedback guys.   I am at the point of the HE install and barring an impending extended belayed xmas shopping spree I hope to install the HE this weekend.   I started Sunday but with HE in hand and looking at the best fit in the duct on the supply side the exhaust tube from the furnace make it awkward to install just above the burner and the condensation line from the A-coil is in the way above.  So I ended up diverting to insulating and running the pex in my crawl space which will connect to the HE.   But I think the best bet on the HE install is to cut the condensation line and re-do after sliding the HE in just below the A-coil.   Devil is always in the details.   After the HE install the only thing left is installing the plate exchanger for the hot water heater and connecting all of the plumbing lines together.  Fill her up, leak test, add chemicals, and fire her up before new years'.  That will be worth a pop of the bottle!

kc
Title: Re: heat exchanger install opinions
Post by: dwneast77 on December 19, 2012, 06:44:34 AM
kc - Amen to that!!  It feels like it'll never be done,  with all that goes into the setup.  But when it's done and fired up, that makes it all worth while.  Good luck!!  Keep us all posted on your progress!!  Happy burning!!