Pex for hot water coil in OWB?

[psu927]

Just tore my hardy H2 apart because I knew the coil had pinholes in it from when I bought it. I thought if it was 1 or 2 I would just repair but the pipe is shot so I was wondering if anyone used pex or similiar pipe for the hot water coil rather than spending a huge amount of money on a copper coil?

 

[hondaracer2oo4]

Don't have any expierence with using pex as a heat coil but I would think it would work just fine as long as the water never boiled which is not something you can gauruntee. When you do put the top back on the hardy make sure that you silicone everything really good around the smoke stack and the edges. Last year I had my h4 sprayfoamed and then halfway through the season the silicone around the smoke stack failed which means I now have steam that makes its way out around where the strack comes up. Its annoying and I have to add water every week or so now. I don't plan to cut around the spray foam though and fix it since it is more of an annoyance than anything else. I know I am way off topic but is there anyway you could send me picks of what it looks like with the top off? As far as the water coil goes, why don't you instead just run the waterline from the boiler through a water to water exchanger for your domestic instead of going the heat coil route and having to run extra lines into the house?

 

[wooddog 066]

yes sir i just made up a hot water preheater for myself and used sharkbites where it hooks up coming from coldwater supply and where it goes to hot water taps is all pex and works great i just just stubbed off the brazedplate with copper like 8" so i could hook the sharkbites to it...and the reason i used them is so i can pull it apart if needed and clean it out..."LIME" darn well water but hope this helps

 

[brokenbudget]

waste of money and will not last.
buy the proper tubing.

 

[upsnake]

Depending on the cost of the copper coil, would it be feasible to eliminate the use of the water heating coil in the wood burner.

Then just insert a plate Hx in the house, inline before the forced air hx / hx for radiant floor.

Then just run your water cold water to the plate, and then dump the hot water into your water heater tank.

I don't have a Hardy so not 100 % how it works, but just a thought.

 

[confused8122]

+10 on a heat exchanger in the house

 

[Butch(OH)]

Several around here with Hardys have abandoned the internal coil approch and went to plates or sidearms. Some because of leaks others because of lag time which can be considerable when the OWB being a long ways from the house. Others use the factory set up and like it. Don't know about Pex for the coil? I would expect that heat transferr will suffer given equal amounts of Pex vs copper?

 

[psu927]

Depending on the cost of the copper coil, would it be feasible to eliminate the use of the water heating coil in the wood burner.

Then just insert a plate Hx in the house, inline before the forced air hx / hx for radiant floor.

Then just run your water cold water to the plate, and then dump the hot water into your water heater tank.

I don't have a Hardy so not 100 % how it works, but just a thought.

This would only heat the water when my house heat is on though.

 

[psu927]

Don't have any expierence with using pex as a heat coil but I would think it would work just fine as long as the water never boiled which is not something you can gauruntee. When you do put the top back on the hardy make sure that you silicone everything really good around the smoke stack and the edges. Last year I had my h4 sprayfoamed and then halfway through the season the silicone around the smoke stack failed which means I now have steam that makes its way out around where the strack comes up. Its annoying and I have to add water every week or so now. I don't plan to cut around the spray foam though and fix it since it is more of an annoyance than anything else. I know I am way off topic but is there anyway you could send me picks of what it looks like with the top off? As far as the water coil goes, why don't you instead just run the waterline from the boiler through a water to water exchanger for your domestic instead of going the heat coil route and having to run extra lines into the house?

While on topic what kind of silicon did you use?

 

[upsnake]

Psu

http://www.arboristsite.com/firewood-heating-wood-burning-equipment/183100.htm

Not sure if this link will work or not..

I had a thread I started a while back about the plate hx.

First off what kind of of heat do you have, Force air or radiant?

Here is how my system is set up.
I have a forced air system.

So the hot water comes in from from the owb, into the house, then into the plate hx, out of the plate and then into the water to air hx in the furnace plenum then back to the owb.

The water from the owb is always running through the plate hx.

The water domestic water is tied to the other side of the plate hx. So as soon as you turn on your hot water, the flow starts through the plate, transferring the heat from the already running water from the owb.

Some people run their hot water directly out of the plate. I chose to run mine out of the plate and into the water heater. It uses the tank as a storage and tempering tank.


Also on this set up you would want to make sure that you have a tempering valve installed on your tank.
I have just a small 10 plate, that cost like 40 bucks.


Hope that was clear and helps.

 

[Encore]

I have two different sets of lines. One set (input and return) for the heat coil in the furnace, and another for the hot water.

This way I get 175 degree water (or whatever temp it is when it reaches the tank) right in the tank. Since my tank draws from the top, it doesn't take long before we have pretty significantly hot water coming out.

It's also much more simple this way. Right now I have the valves to the furnace heat coil shut off so that no water is naturally convecting through my furnace (especially since we have the AC on lol) but I do fire it up once a week or so for a couple hours when we are doing a lot of laundry or the whole family is taking showers at once (typically weekends) so all the heated water is going right into the tank, without heating up the coil in my furnace.

We don't have any coil going into the water heater, just shut off valves to direct the water. Incoming fill water is directly from the Hardy.

I may not be explaining it well. I could probably take a picture

 

[psu927]

Psu

http://www.arboristsite.com/firewood-heating-wood-burning-equipment/183100.htm

Not sure if this link will work or not..

I had a thread I started a while back about the plate hx.

First off what kind of of heat do you have, Force air or radiant?

Here is how my system is set up.
I have a forced air system.

So the hot water comes in from from the owb, into the house, then into the plate hx, out of the plate and then into the water to air hx in the furnace plenum then back to the owb.

The water from the owb is always running through the plate hx.

The water domestic water is tied to the other side of the plate hx. So as soon as you turn on your hot water, the flow starts through the plate, transferring the heat from the already running water from the owb.

Some people run their hot water directly out of the plate. I chose to run mine out of the plate and into the water heater. It uses the tank as a storage and tempering tank.


Also on this set up you would want to make sure that you have a tempering valve installed on your tank.
I have just a small 10 plate, that cost like 40 bucks.


Hope that was clear and helps.

Ok I gotcha. I have mine setup now so the circulator only runs when my furnace calls for heat. (doesn't run all of the time). Forced hot air BTW. The price on these exchangers has dropped a lot from what I remember them being 4-5 years ago. Is that your tempernig valve on the left side of the top picture?

 

[wooddog 066]

Domestic water heat exchanger

I guess i didnt say it right neither but i have my system setup like upsnake and works WELL for me!!!:yoyo::msp_biggrin:

 

[upsnake]

This might help. Here are the labels of what is going on with the plate hx.
I just went and looked at online stores "heating" stores that are selling plates and they are way more than what I paid. I got mine at an alt energy, diesel making type store online. (not sure if allowed to give the name of the place on here or not).

The image here is in summer mode, ( I don't currently run the owb in the summer. I set the system up to be able to if I ever wanted to but with just two ppl at home it is not worth it right now.

The water just bypasses the plate hx, and goes directly down into the tank just like any other DHW.

K so this is bad angle for the picture but. Basically i have a valve right before the water to air hx to stop the flow from the owb if I ever needed to do anything to the hx.
So what I did was just put a bypass in the pex, from supple to return. I can close the valve at the w2a, then open the bypass, and it will just loop back skipping the furnace hx.

I had to do the weird little design i did b/c the two pex lines were too close together to do it how my last pic is. View attachment 250656

View attachment 250654View attachment 250655

 

[woodfarmer]

How many gallons is your hwt tank? Is the plate hx in the top right corner of the picture, up in the floor joists?

 

[upsnake]

It is a 40 gallon tank.
yes in the upper right hand corner is the plate. It is somewhat sitting on the bottom strip of wood of the floor joist / but mostly is supported by the pex and copper piping.

 

[woodfarmer]

so if im heating a 1500sf slab, dhw, a couple rads upstairs and a hot tub, would you recommend the 40 gallon to be my back up. i have an empyre elite boiler, but im usually away from home one or two days a week. How would you recommend i run my system?
I was just going to let the propane hwt tank tun when i dont have a fire going or is there a better way?