Water to water side arm

[Ohiowood]

Has a water to water heat exchanger ever fail ?  If so is the chemicals that are put in the CEntral Boiler dangerous for you health if it got into your drinking water?

[beenthere]

Likely not healthy to drink, but on the other hand, the heated water likely wouldn't be going to an outlet serving drinking water.
But would be prudent to determine ahead of time if drinking it is a possibility if there is a failure.

What type of system are you considering?

[r.man]

A failure is always possible but in this case I would not expect contamination since the house water is under much more pressure than the furnace water. If a failure occurred I think that the furnace would overfill but the house water would be fine.

[Slabs]

I was gonna say that too.  I had a fill valve leak and overpressured the boiler once.  No damage though.  Welded plate Federal Boiler is pretty strong.

[Holmes]

I agree with r.man...

[beenthere]

And the boiler has a low pressure relief valve, or should have. Maybe 30 psi ?

[NWP]

The way my water to water sidearm is designed, the tubing would have to corrode through in order to get mixed.  I have wondered about the possibility of it though.  I hadn't thought about the house system having more pressure, but that makes sense that it would go into the boiler system instead of vice versa.

[Logging logginglogging]

could someone post some pictures of these water to water sidearms?

[NWP]

 

 



 



 

Here are pictures of my sidearm.  The last picture is of another sidearm that isn't put together.  The water comes out the water heater through the bottom pipe and up through the water jacket and back into the water heater through the top pipe.  It is supposed to due this by convection but mine never seemed to work right so I put a circulator pump on it.  The water from the Heatmor comes in the white pex tubing at the bottom of the water jacket and exits at the top and goes on to the exchanger above the air handler.

[beenthere]

Here is my 'sidearm'.
It is a 30 gal stainless steel tank with a copper coil inside that the wood heated water flows through by convection. Works when there is no air trapped at the top. This 30 gal of water is between the cold supply line and the 'cold' input line to the gas hot water heater which keeps the temp of the hot water up if it needs to be topped off.


 

[NWP]

That's a pretty cool deal.  You've got a lot of hot water there.  Did you make that specifically for the water heater or was it designed for something else?

[beenthere]

NWP
I bought it from the company that made the wood boiler. Company is out of business now. They were located in Babbitt, MN back in the early to mid 80's.
It's been a fool-proof design for 30 years for me.
Even in the summer, that 30 gal of water will reach some room temps that feeds the hot water heater. In the winter, it just gives off some heat that is great to snuggle up to when coming in from the cold.

[Logging logginglogging]

thanks for the pictures guys... i want one of these.....
Just to clerify.... using these before the hot watter heater, you are esentually feeding pre heated water into to cold water input on the hot water heater and it will not damage the hot watter heater?

[trapper]

Most of them circulate the water already in the water heater keeping it hot. I installed a new water heater when I put in the owb 8 years ago and havn't turned it on yet.  Never run out of hot water unless one granddaughter fills the tub and I want to take a shower right after.  Take my shower first and everybody happy.

[beenthere]

Just to clerify.... using these before the hot watter heater, you are esentually feeding pre heated water into to cold water input on the hot water heater and it will not damage the hot watter heater?

How could warm water plumbed into the cold input cause any damage?

[Logging logginglogging]

Just to clerify.... using these before the hot watter heater, you are esentually feeding pre heated water into to cold water input on the hot water heater and it will not damage the hot watter heater?

How could warm water plumbed into the cold input cause any damage?

well i was thinking it could cause the hotwater heater circutry to get overheated, or somthing like that.
I just wanted to know befor i do this myself. I think it would be great to save of eletric costs. if i could find a large sidearm / tank I would preheat even more water just to get more hotwater too..

[beenthere]

Likely not a problem.
The temp control in the hotwater heater will kick the heating elements on if the water temp needs to come up, but if the water temp is above the set point, then nothing happens (no electricity used) and no way to overheat.
Have the proper relief valves in place for code and assurance that it is safe.

[Logging logginglogging]

Likely not a problem.
The temp control in the hotwater heater will kick the heating elements on if the water temp needs to come up, but if the water temp is above the set point, then nothing happens (no electricity used) and no way to overheat.
Have the proper relief valves in place for code and assurance that it is safe.

We are lucky here we have no building codes ...so as long as it works and is safe i am happy.
I am gonna check out what they have for hotwater side arms at my local boiler dealer

[Draco]

I use the plate heat exchanger on page 8 of this parts catalog:

http://www.centralboiler.com/media/CBCatalog.pdf

It takes up very little space and keeps the water in my water heater plenty hot.  I live alone, so don't have to be concerned about others scalding themselves.  I do have an anti scald valve set high.

Set your water heater to "vacation" when you install a water to water exchanger.  If not, as soon as some cold water starts to take down the temperature, your gas/electric will kick in, defeating your original purpose.

[upsnake]

Yup pretty much the same as Draco.

Turn my temp settings down to pilot.
Then let the plate do the work.  I just have a little 10 plate 50 dollar one, and it keeps up with everything i have thrown at it. (shower, washing machine and sink all at the same time).

The only risk you may have is some gas water heaters have a non reset able high temp switch in the gas valve, if you trip that your valve is toast.

I ended up not going the side arm route b.c of that, (am sure it would be fine), but i didn't want the water just recircing in there getting hotter and hotter.

[trapper]

It dosn't get any hotter than the water in the owb.

[Logging logginglogging]

It dosn't get any hotter than the water in the owb.

well no it cant since thats whats heating it.

[Logging logginglogging]

I have an eletric hot water heater. What setting should i set that to? coldest possible?
then let the sidearm do the work?

[Logging logginglogging]

Also, pros and cons of Plate exchanger vs Tube like side are also on page 8 of that PDF?
I just dont understand how the side arm hookups can produce enough hot water to matter? I mean they only hold a gallon or two, and they are installed before the hot water heater. they then go into the hotwater heater. Does it honestly save that much on hotwater eletricity? We dont use a ton of hot water. I feel like I am missing somthing here since the benifit just dosent seem that huge. I can see how the big big sidearm with a coil in it would be benificial since it holds so much water.

[beenthere]

lll
I leave my hotwater heater set at the temp I want my hot water to be at. Don't change anything as the heat will only kick on if the water temp in the heater is below set point.

If I just wanted the temp of the wood-heated water regardless of what that is, then I'd set the hotwater heater to the lowest acceptable temperature.

You have a concern here that I'm having trouble trying to figure out, but hope we can help (or that I can get it through my thick head ).