# water to air heat exchanger location??



## treesforheat (Nov 2, 2011)

Have picked my furnace, arrives (I hope) in 4 weeks or so.... (Portage and Main 250 gasser), trying to plumb up things before it arrives and pour pad etc.... question on plumbing.... I was all set to locate the water to air heat exchanger just above the "A" coils on two existing furnaces... both identical.... except one has a box leaving up and other has round tube. 

A guy I was just talking to who just installed an outside water furnace with a central heat and air existing system told me his installer told him they needed to (and did) install the hot water heated water to air heat exchanger IN the return side, right next to his furnace because if located IN the exiting air flow, it would hinder and upset his Air Conditioning output in the summer more in that location. 

Which is best, supply or return air side and if it's in the return wouldn't that overheat after exposure the motor spinning the fan, and if in the supply side restrict the Air Conditioner flow and maybe sweat being right in the coldest air hitting it right out of the "A coil" output flow in the summer?? Any thoughts would be appriciated. Eastern Tennessee....


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## goosegunner (Nov 2, 2011)

Not sure about putting it on the return side. 

Mine is above the a coil. I put valves and unions on each pex line so I can remove it in the summer takes 20 minutes or so but I do think it helps my air conditioner.

gg


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## Frozen Canuck (Nov 2, 2011)

Best location is after the fan in the supply duct, not on the return side, far too inefficient to have them in the return duct. Also putting them in the return would expose your inner workings to higher temp air as opposed to the slightly below room temp air that they were designed for.

My coils like goosegunner are removable for summer time A/C. Strongly suggest you do so as well as A/C needs far more CFM than heating to get the job done.


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## treesforheat (Nov 2, 2011)

goosegunner said:
			
		

> Not sure about putting it on the return side.
> 
> Mine is above the a coil. I put valves and unions on each pex line so I can remove it in the summer takes 20 minutes or so but I do think it helps my air conditioner.
> 
> gg


That thought did cross my mind but wasn't sure how much trouble it might be..... makes excellent sense to me! thanks, Edwin


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## treesforheat (Nov 2, 2011)

Frozen Canuck said:
			
		

> Best location is after the fan in the supply duct, not on the return side, far too inefficient to have them in the return duct. Also putting them in the return would expose your inner workings to higher temp air as opposed to the slightly below room temp air that they were designed for.
> 
> My coils like goosegunner are removable for summer time A/C. Strongly suggest you do so as well as A/C needs far more CFM than heating to get the job done.


      thanks for the great advice, I'll do likewise...... Edwin


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## goosegunner (Nov 2, 2011)

Not sure how you are going to control your gas furnace/ boiler heat.

I also have an aqua stat at the coil in the supply line. It is connected to a time delay a 2 RIB relays. If the water isn't the temp you set after the time you chose it will cut power to the pump and the gas furnace kicks in.

I use 130 degrees after 3 minutes.  It works well and allows me to use one thermostat. Just set the heat to what you want.  It was set that way after discussions with my hvac guy and  I how I wanted the system to perform.  I wanted it as seemless as possible, especially for when I am gone.

gg


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## stee6043 (Nov 2, 2011)

goosegunner said:
			
		

> Not sure how you are going to control your gas furnace/ boiler heat.
> 
> I also have an aqua stat at the coil in the supply line. It is connected to a time delay a 2 RIB relays. If the water isn't the temp you set after the time you chose it will cut power to the pump and the gas furnace kicks in.
> 
> ...



The easiest way to control a furnace blower without activating the burner is to utilize the air conditioning circuit.  Two thermostats, one wire, very easy.  Throw the breakers to your AC unit in the winter and enjoy...


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## goosegunner (Nov 2, 2011)

stee6043 said:
			
		

> goosegunner said:
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Does the boiler pump continue to run if the water is not hot?

Doesn't your Air conditioning side run the fan at a higher speed?

I work 24 hour shifts so I wanted heat without anyone knowing the difference if the wood boiler ran out of wood or if the water cooled down.  It will be different now this year with storage. I switched my primary manifold pump in the garage to on demand only. It seems to work so far and should help keep tank from mixing. I might have to play with the time delay when it gets colder.

gg

Gg


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## treesforheat (Nov 3, 2011)

goosegunner said:
			
		

> Not sure how you are going to control your gas furnace/ boiler heat.
> 
> I also have an aqua stat at the coil in the supply line. It is connected to a time delay a 2 RIB relays. If the water isn't the temp you set after the time you chose it will cut power to the pump and the gas furnace kicks in.
> 
> ...


     Me neither!    You guys are good swimmers in this stuff, I'm still only ankle deep.  I'm leaning towards  a wet thermostate at the furnace (pump from there) in my primary supply line, and I'm with you, need to shut it down if out of wood or my backup gas unit will be heating my stove water...  :-(     that seems from what I've read a low temp to drop that stove too... creosote??? but like I said, I don't know beans about this, but reading everything I can. thanks for the info... hadn't thought of that one.. gees, the learning curve is steep, but smoking it over here with you guys that live and breathe this is cheap, learning on my own after many trials and errors ain't...thanks again, Edwin


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## goosegunner (Nov 3, 2011)

My original set up was with a Taylor 450 OWB.  It worked well but smoked a lot.  With the exhanger i have it will heat the house down to about 130 degrees but it is not as comfortable as the high temps. Now I have the Econoburn and with the storage The boiler doesn't go low because the load draws from storage. My boiler will be off more of the day than it is running. It is also protected by a Danfoss valve.

gg


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## goosegunner (Nov 3, 2011)

I looked back and saw that you are getting the Portage and Main, those things look pretty nice!. Some people like to have the coil heat the water  a little and send it back to their outside unit if the fire goes out and gas furnace kicks in. 

I didn't find it necessary when I ran my OWB. I did run my pump 24/7 to the primary/secondary manifold in my garage. My furnace sends a signal to a Taco zone controller that kicks in the secondary pump.

The primary is now set for on demand when any zone calls for heat. You can get different zone controls that can be set to cycle for freeze protection or to exercise pumps in the off season.

gg


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## stee6043 (Nov 3, 2011)

goosegunner said:
			
		

> stee6043 said:
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I have two circ pumps in my system.  One to send water through my HX (in the furnace plenum) and one that sends water to storage.  I use the AC circuit to turn on both my furnace fan and my second circ pump using a relay.  My furnace fan only runs at one speed...

As for "seamless" operation of both I leave my gas furnace thermostat set at 66 degrees all winter long.  If for some reason my wood boiler were to stop working properly while I'm away at work the gas furnace will kick on all by itself at 66 degrees.  My wood burner thermostat stays at 70...or 71 depending on my mood.


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## goosegunner (Nov 3, 2011)

Sounds like you have it dialed in pretty well with your setup.  Do you have two separate thermostats or use a multi input one?

We still have the old school dial honeywell. We turn the heat down at night to 66 and 70 during the day. I thought about using a dual input one for wood one for gas but I did not want to mess with both settings when we turn down at night.

gg


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## treesforheat (Nov 4, 2011)

goosegunner said:
			
		

> Sounds like you have it dialed in pretty well with your setup.  Do you have two separate thermostats or use a multi input one?
> 
> We still have the old school dial honeywell. We turn the heat down at night to 66 and 70 during the day. I thought about using a dual input one for wood one for gas but I did not want to mess with both settings when we turn down at night.
> 
> gg


 Ain't nothing wrong with simple.....  I haven't gotten that far on my planning... controls. Have a bunch of Heating and Air guys at the Reactor I can ask when I get to that phase...  I'll try and go as simple as possible, but these "propeller heads" are into the latest and greatest systems.... very complex some of the guys are running on this site too.....  I'm not that smart in that area... be another "learning curve" for me.... thanks for the comments! Edwin


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## rkusek (Nov 4, 2011)

One thing you do not want to do is circulate water thru the HX while your gas or electric backup is making heat.  The HX works just as well in reverse keeping your boiler water toasty warm.  Two tstats, an aquastat , and a relay will allow you avoid this pretty easily but I still have to set the backup a couple degrees cooler.  It would take a fancier off the shelf or a custom tstats to avoid this


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## goosegunner (Nov 4, 2011)

huskers said:
			
		

> One thing you do not want to do is circulate water thru the HX while your gas or electric backup is making heat.  The HX works just as well in reverse keeping your boiler water toasty warm.  Two tstats, an aquastat , and a relay will allow you avoid this pretty easily but I still have to set the backup a couple degrees cooler.  It would take a fancier off the shelf or a custom tstats to avoid this




That is one of the conditions I wanted to avoid.

 I have one thermostat, set the temp you want. If the water isn't 130 after 3 minutes one relay shuts off the pump, another relay starts the gas furnace.

Same old dial honeywell thermostat we have always had. With my setup it is one or the other. If wood boiler water isn't at proper temp, flow stops, gas furnace starts.

gg


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