Print

[ohiomatt]

I just got my owb installed this past weekend, however cannot seem to get hot water for my dhw. I believe it is a 10 plate exchanger. It is before the hot water heater and has one 1" line coming from where the relief valve is and a 1" line coming from the drain in the tank. The plate exchanger is sitting on the floor.  I have been told you don't need a pump to circulate water through the plate exchanger it naturally will cycle through. Is this correct? I have to keep turning on the electric because its never hot and when it is it only last like five minutes. Thanks for the help

[yoderheating]

 If you are installing a flat plat it works best to put inline or have a pump circulating.

[RSI]

I don't think a flat plate will work very well like that. They don't have as direct a route as a side arm has so won't circulate very good.

You probably will have to either add a pump, replace it with a side arm or move it so it is in series with the cold water line into the tank.

[dirtryder]

If you want on demand hot water....as much as you can use, move the plate exchanger to the hot line coming OUT of the hot water heater. Turn off your hot water heater and it becomes a cold water storage tank. When you open your faucet, cold water will leave the HWH and be instantly heated by the plate giving you hot water. I know many will flame me, but, I have no clue why anyone would want to try and heat the water going into the HWH for it just to sit there. When I shut down my wood boiler, I just re-light my propane HWH and everything works fine. I do not lose any heat from water running through the exchanger (because boiler circ pump is off) If that concerns you, it is very easy to install a by-pass for when you use your HWH again.

[Ridgekid]

dirtyryder-

I put mine on the IN side of my HWH because my 50 gallon HWH becomes a storage tank. The tank also acts like a mixing valve, making sure the water coming out of the faucet isn't 185F. (I avg 165F right now) Without this setup I would be storing 50 gallons of 52F water waiting to be heated.

[muffin]

I have mine on the out side of the tank too.  this way I can shut the tank completly off.  Otherwise you have to leave the tank on and you are just pre-heating the water so you never run out.  You will still consume a little energy to keep that tank hot though.  I would guess it would be minimal though.  I have a mixing valve installed to temper the water.  Seems to work great.  The tank is off and I have infinite hot water.  I do circulate the water through the plate exchanger.  I thought you had too.  I thought the side arms where the only ones you did not have to because they use convection to circulate the water.

[yoderheating]

Two problems with putting the flat plate on the hot side. 1 More fluctuations in water temps. 2 If your outdoor furnace goes out and the water cools you will be cooling your hot water.
 It is not true that you have to leave your hot water heater on to maintain hot water in the tank if you heat the cold line. I have installed hundreds of these things and have never had to leave on the hot water heater. The only case I can think of is if it was a shop or cabin where there would be a number of days between hot water demand. In that case I would maybe consider heating the hot side. 

[Ridgekid]

yoder-

I didn't think I wanted to turn off the electric to my HWH, but I did. And so far we are not having any issues with maintaining HW water. So it's a good point if your looking to save electric like we are.

[yoderheating]

I find it very satisfying knowing that the hot water heater can not come on and run my power bill up. My bill is normally around $80 when I'm running the furnace. My father inlaw has really focused on eliminating electricity usage and has had bills below $40. I installed a infloor/radiator system hooked to a MF5000HE at his place. All that he needs to heat his home is two small pumps running. I know I'm crazy but stories like that get me excited.

[dirtryder]

dirtyryder-

I put mine on the IN side of my HWH because my 50 gallon HWH becomes a storage tank. The tank also acts like a mixing valve, making sure the water coming out of the faucet isn't 185F. (I avg 165F right now) Without this setup I would be storing 50 gallons of 52F water waiting to be heated.

Ridge, why on earth do you NEED to keep 50 gallons of water hot when you can just turn on the faucet, walk away, and have hot water all day........but whatever works.....

[dirtryder]

1 More fluctuations in water temps. 2 If your outdoor furnace goes out and the water cools you will be cooling your hot water.

Well, I forgot to mention that I have a mixing valve installed, which I feel you MUST have running it this way, so #1 does not happen.

As for #2. If your furnace cools down to the point of no hot water.......if the circulater pump is turned OFF, and you then turn on your HWH and let it warm up, (I have never needed hot water so quick that I couldn't wait for it to heat itself up first) it has no effect on the hot water. At least mine doesn't.  Maybe just a slight length of time for faucet to heat up, but nothing to write home about. Without the boiler water moving, there is no heat transfer in the HX.
And if you are not home to turn off the pump.....who needs hot water?
But, like I said, to each his own........free hot water, no matter how you get it........is still awesome

[Ridgekid]

You think YOU get excited about electric use? Check out my current electric chart in my gallery. That's impressive for NOT having city water/sewage and operating two dusk to dawn lights! I may not get my electric as low as you, but that's the ONLY utility I pay for. (phone and dsl is paid by employer)

[yoderheating]

  The one reason to have 50 gals of hot water is if the furnace ever does go out. I guess different situations work differently. I know here at my place I may be gone 18+ hours on a cold day if I have a lot of service calls to do after an install. There have been times in the past where the furnace was almost out and the water temp was dropping by the time I get home. By having 50 gals of water already hot my wife doesn't even know the furnace is loosing temperature, she can continue using hot water until I get home and build back up the fire. Not that it happens very often but it does maybe several times a year.And before you ask, no she doesn't want to mess with the furnace and thats fine with me.
 Also, as a dealer I can't tell you how many times some customers let their stoves go out. I know most of the folks on this forum are very attentive to their furnaces, but there are a lot of people out there who load them only when the air out of the vents gets cold. Its not abnormal for some people to call me several times a year about problems that end up being them actually not having any wood in the stove. I would guess I would get twice the calls if I plumbed the flat plate in the hot side because the water temp would drop every time they forgot to put wood in the stove. So as a dealer/installer it makes a lot of sense to plumb it in the cold side. As a responsible home owner it makes more sense to plumb it in the hot side. Hope all this makes sense. 

[ohiomatt]

So if I need to add a pump to this setup, what pump do I need? Also the guy who installed this for me says that this is how he has been doing them and it worked fine for everyone else.

[dirtryder]

  The one reason to have 50 gals of hot water is if the furnace ever does go out. I guess different situations work differently. I know here at my place I may be gone 18+ hours on a cold day if I have a lot of service calls to do after an install. There have been times in the past where the furnace was almost out and the water temp was dropping by the time I get home. By having 50 gals of water already hot my wife doesn't even know the furnace is loosing temperature, she can continue using hot water until I get home and build back up the fire. Not that it happens very often but it does maybe several times a year.And before you ask, no she doesn't want to mess with the furnace and thats fine with me.
 Also, as a dealer I can't tell you how many times some customers let their stoves go out. I know most of the folks on this forum are very attentive to their furnaces, but there are a lot of people out there who load them only when the air out of the vents gets cold. Its not abnormal for some people to call me several times a year about problems that end up being them actually not having any wood in the stove. I would guess I would get twice the calls if I plumbed the flat plate in the hot side because the water temp would drop every time they forgot to put wood in the stove. So as a dealer/installer it makes a lot of sense to plumb it in the cold side. As a responsible home owner it makes more sense to plumb it in the hot side. Hope all this makes sense. 

Yoder......that stuff never crossed my mind.....I guess when you put it that way it makes sense......waiting for cold air to see if you need wood