Making a External DHW Coil

bug512 wrote:I like the tank on top of the stove. So is it cold going in, then out to your regular source of heating water? Would insulating the top portion of the tank help with keeping it warm?

BTW, I had 117 deg this morning.

No actually mine isnt for domestic but I thought the concept of external fit this thread somewhat.

we cut in to the baseboard circut with a ball valve then tee'd down from both sides of it to give the ability of choking the flow both thru the tank and bypass . it has a huge effect on the temp of the circulated water and keeps the aqua-stat from firing the burner. the domestic water is made in a heat-exchanger/storage tank for the baseboard so in effect the stove heated baseboard BTU's also heat the domestic!

if during times the t-stat isnt calling the taco is off yet thermosiphon still works keeping all toasty. I doubt it will ever over temp and if it does I plan a variable taco ....

WNY wrote:Another success story! Did you put a tempering valve in, in case it gets too hot and you don't scold someone...Love the labeling.

Yes, I put the tempering valve in on Friday morning when I put the system on-line. This valve is unbelievable I set it for 119 deg and it stays there no matter what. I will snap a picture of that later or when I make the video.

Thanks again for all the advice and ideas.

Poconoeagle wrote:

bug512 wrote:I like the tank on top of the stove. So is it cold going in, then out to your regular source of heating water? Would insulating the top portion of the tank help with keeping it warm?

BTW, I had 117 deg this morning.

No actually mine isnt for domestic but I thought the concept of external fit this thread somewhat.

we cut in to the baseboard circut with a ball valve then tee'd down from both sides of it to give the ability of choking the flow both thru the tank and bypass . it has a huge effect on the temp of the circulated water and keeps the aqua-stat from firing the burner. the domestic water is made in a heat-exchanger/storage tank for the baseboard so in effect the stove heated baseboard BTU's also heat the domestic!

if during times the t-stat isnt calling the taco is off yet thermosiphon still works keeping all toasty. I doubt it will ever over temp and if it does I plan a variable taco ....

OK, nice. It is great to "capture" the energy slowly and release it when needed. This is all good stuff..

what kind of temps do you have at the pipe near the coil?
if the temps arent over 200 degrees i'll use cpvc for piping to my external coil......i have a brand new ac condensor for a volvo 760 that I am planning on putting on top of my alaska under the cast iron covers......the price of copper is scary, and I have a bunch of 1/2" cpvc pipe and fittings left over......also saving up for the circulator pump.

Question:

If I were to run several loops on both sides of my furnace and cover them / insulate / reflect and have a small pump, do you think that the temperature would get high enough (with furnace on heating), that I could take some of the 'wasted' heat that I am recovering and pump it into a duct with an air / water HE and help warm another area of the house?

I am not looking for DHW. I have my house zoned in 2 sections - the 'bedroom' area gets little or no heat during the day - but if I could capture some of the radiated heat from the furnace and pump it into the ducts for this area of the house, it would be a win / win situation.

In order to get the temps UP (want much more than needed for DHW), I would have all the loops in series, not parallel. Rather than finned tubing, I was going to use 1/2" copper tube, anchored directly to the outside wall of the furnac with conduit clips (I have no problem drilling / tapping into the the furnace shell and like the idea of direct contact to get temps up with non-finned tube. Surface temp of the furnace when running is 340 F or so.

A small circulator would ensure that the water won't boil, along with common-sense expansion and relief devices.

I like the t-stat, where you get them and how they work, I want to do the same, thank, Gerard

lincolnmania wrote:what kind of temps do you have at the pipe near the coil?
if the temps arent over 200 degrees i'll use cpvc for piping to my external coil......i have a brand new ac condensor for a volvo 760 that I am planning on putting on top of my alaska under the cast iron covers......the price of copper is scary, and I have a bunch of 1/2" cpvc pipe and fittings left over......also saving up for the circulator pump.

Around the coil the stove surface temperatures can be up to 400 depending on how the stove is firing.
I think your CPVC will be fine for water transfer away from the stove, I would use copper for the first one to two feet off of the coil.
As far as the automotive condenser, I do not know what kind of solder they use and if would be safe for your domestic (drinking) hot water. I do not know if I would trust it even after cleaning and sanitizing.

crazysteamer wrote:Question:

If I were to run several loops on both sides of my furnace and cover them / insulate / reflect and have a small pump, do you think that the temperature would get high enough (with furnace on heating), that I could take some of the 'wasted' heat that I am recovering and pump it into a duct with an air / water HE and help warm another area of the house?

I am not looking for DHW. I have my house zoned in 2 sections - the 'bedroom' area gets little or no heat during the day - but if I could capture some of the radiated heat from the furnace and pump it into the ducts for this area of the house, it would be a win / win situation.

In order to get the temps UP (want much more than needed for DHW), I would have all the loops in series, not parallel. Rather than finned tubing, I was going to use 1/2" copper tube, anchored directly to the outside wall of the furnac with conduit clips (I have no problem drilling / tapping into the the furnace shell and like the idea of direct contact to get temps up with non-finned tube. Surface temp of the furnace when running is 340 F or so.

A small circulator would ensure that the water won't boil, along with common-sense expansion and relief devices.

I guess my first question is when you say furnace, do you mean your oil or gas fired hot air furnace?
How often does it run? % of time in a hour?

Pumping water through 1/2" copper tubing you will need to throttle back on the flow. Too much flow you will not have enough residency, too little the water will be heated to its maximum half way through the path of the coil. This is why I like the a supply and return header with pipes in between. So if I supply the coil with 10 gpm that will get divided between each row, so if you would have four rows it would be 2.5 gpm

A heating application is going to take a lot more energy (heat) then heating domestic hot water. But you will not know until you try.

Good luck

gwjwbw wrote:I like the t-stat, where you get them and how they work, I want to do the same, thank, Gerard

Grainger has them "Panel mount Thermometer"

I tape the sensing element onto the pipe and then wrap with pipe insulation. Granted this will give you surface temperature, but with it securely taped and insulated it will be very close.

BUG512

It's a coal furnace, extenal temps are 350 when running.

during the day, I heat the main end of the house and leave the bedroom area cold.

if, when heating the main area I can suck up some 'free heat' and put it into the bedroom area, it is free, even if it isn't much. Basement is VERY WARM.

totally agree on the need to throttle and or long tube. Planning on a couple of 100 feet of tube total to ensure that I can get the heat I need - and will still have a throttling valve on the discharge to regulate temps.

Gene what are the pictures of the Humidifier and what looks like a float in your Flickr file? Is it connected to your heating system?

Adamiscold wrote:Gene what are the pictures of the Humidifier and what looks like a float in your Flickr file? Is it connected to your heating system?

Nope, it is not connected to the heating system. Here is the story. I'm sure you are familiar with the cabinet style humidifiers, like the ones from Sears.. Well I was thinking of another way to feed the humidifier water instead of filling the supplied water containers. So I found this mechanical water float in the Grainger catalog. It has a 1/4" copper tubing fitting on one end (like a bulkhead fitting).
Grainger # 2ZDR5

I then hooked it up to a cold water line. This automatically keeps a water level in the humidifier. The humidifier ran all last season without a problem. I need to stop by sears this weekend to get replacement filter/wicks.

I hope this is a good explanation.

bug512 wrote: Nope, it is not connected to the heating system. Here is the story. I'm sure you are familiar with the cabinet style humidifiers, like the ones from Sears.. Well I was thinking of another way to feed the humidifier water instead of filling the supplied water containers. So I found this mechanical water float in the Grainger catalog. It has a 1/4" copper tubing fitting on one end (like a bulkhead fitting).
Grainger # 2ZDR5

I then hooked it up to a cold water line. This automatically keeps a water level in the humidifier. The humidifier ran all last season without a problem. I need to stop by sears this weekend to get replacement filter/wicks.

I hope this is a good explanation.

That's a neat little idea Thanks for the explanation.

This idea of the float valve in the cabinet without an overflow waste to drain vent, will not represent (to me) the sharpest tool in the shed idea.

IF -- and yes I read how you had no trouble ALL last season - but just allow me to if this

IF that valve sticks open for any reason-- something fowls the float inside the cabinet or a grain of ? stops the valve from closing...or God know what.

Well

Even a 1/4 inch line can flow enough liquid to bestow you with a VERY unpleasant surprise. I can just see you padding into the room - with the morning fog still over your eyes - can you feel your socks becoming wet? Ill bet it wasn't the dog that had an accident.

Good points Sting (This was also our old Black Labs name), this humidifier is located in the basement (where the coal stove is). If indeed the float/valve would fail the water would run along the basement floor to the sump pump basin. Then provided the basin would fill to the pump on level, the pump would start and disperse of the water. Again this is all provided that there is power being supplied to my house and the pump operates flawlessly.

Can you imagine if your toilet float would stick and the overflow would clog? OMG.. what a mess. And if it was on the second floor..WOW

What if....