Hot Water Circuit in Harman Hand Fired

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michaelanthony
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Hand Fed Coal Stove: Vigilant 2310, gold marc box stove, vogelzang pot belly coat rack
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Coal Size/Type: Coal Contractor's stove, a little Kimmels 'nut
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Post Fri. Feb. 21, 2014 8:52 pm

Is this a single wall hole? And if so would it be easier to plug the old and relocate new holes with the exact size hole saw?..my $.02
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Cap
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Hand Fed Coal Stove: Harman SF 250, domestic hot water loop, heat accumulator
Coal Size/Type: Nut and Stove
Other Heating: Heat Pumps
Location: Lehigh Twp, PA
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Post Sat. Feb. 22, 2014 1:05 pm

Job completed. Dave from Leisure Line sent me the locking nuts and washers for the Hilkoil hot water loop. Dave, thank you. This was a huge help!

I found two old drill bits I didn't know I had. A ⅞" & 1 1/16" bits. How lucky is that? I gathered these bits together when I installed the first water loop 8 yrs ago. Opening up the holes from ¾" to 1 1/16" was very easy as the bits still very sharp. Much easier than anticapeted.
IMG_0247.JPG
Nasty looking! Huh? You can see rust & corrosion due to old loop leaking.
This particular water loop not really designed to fit in this position. The Hilkoil directions show the extensions going out the back of the stove but with the Harman SF250 the back wall is a "double wall". So I could either use additional pipe fittings mounting it sideways/longways or installing at the hottest part of the stove, which is what I did. I had to cut the loop to just slightly longer than the width of the stove to get it in place. This was a headache!

Doing it this way I was unable to use ¾" npt fittings outside of the stove. Not enough taper or threads left over. So, I silver brazed ¾" od refrigeration tubing internal to the water loop. From there I transistioned back to my ¾" ss tubing using the same Sweg-lok fittings. Luckily I has some additional ferrules.

Soft solder 95/5 not an option here. My stove easily exceeds 500F. 50% silver liquifies at 1425F. My silver brazing joints aren't the prettiest but I had to sweat these connections in place. And stainless silver brazing is very tricky. You cannot use sol-phos AG-15, must be high silver AG-45 or better.

I am expecting that my old water loop will have out performed this small one but that that may not be a bad thing. Will know more in a few days.
IMG_0246.JPG
Cutting the extension forced me to an alternative method of transition, silver brazed.
IMG_0245.JPG
Silver brazed copper to 304 SS.
Cap
Lehigh Twp.
Northampton Co., PA

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Lightning
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Hand Fed Coal Furnace: Overmodified/Bored out Clayton 1537
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Post Sat. Feb. 22, 2014 2:37 pm

Awesome job! You gonna do a thermo syphon to a temper tank in front of your hot water tank plumbed in series? This is how my set up is. Have you applied any water pressure yet to the new coil?

That old leaky coil was no doubt stealing a hefty chunk of btus to vaporize the leaked in water.


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plumberman
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Stoker Coal Boiler: coal gun 130
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Post Sat. Feb. 22, 2014 3:21 pm

future food for thought on hole saw drilling, drill hole in block of wood first, place block of wood over previous hole, clamp, have someone hold block, start drilling hole, once hole is started hole saw will guide it self

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Cap
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Posts: 1581
Joined: Fri. Dec. 02, 2005 10:36 pm
Hand Fed Coal Stove: Harman SF 250, domestic hot water loop, heat accumulator
Coal Size/Type: Nut and Stove
Other Heating: Heat Pumps
Location: Lehigh Twp, PA
Contact:

Post Mon. Feb. 24, 2014 10:24 am

Lightning wrote:Awesome job! You gonna do a thermo syphon to a temper tank in front of your hot water tank plumbed in series? This is how my set up is. Have you applied any water pressure yet to the new coil?

That old leaky coil was no doubt stealing a hefty chunk of btus to vaporize the leaked in water.
No. I do not have a thermo syphon temper tank. Is this used to mix hot & cold water for optimal temps?
And yes, I was losing btu's, I noticed the difference in coal use when I shut down the old coil.
Cap
Lehigh Twp.
Northampton Co., PA

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Lightning
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Joined: Wed. Nov. 16, 2011 9:51 am
Hand Fed Coal Furnace: Overmodified/Bored out Clayton 1537
Coal Size/Type: Anthracite/Awesome Size
Location: Olean, NY

Post Mon. Feb. 24, 2014 10:41 am

Hot Water Coil Project

The temper tank is more or less an extra storage tank. The water in it is constantly being turned thru the coil by way of natural convection.

Whenever hot water is used, the preheated water from the temper tank flows into my electric tank so that the electric tank doesn't need to work very hard to bring the water up to 130 degrees.

During times of cold weather when I'm pushing the furnace harder, my preheated water goes beyond 130 and the electric tank doesn't come on at all..


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plumberman
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Stoker Coal Boiler: coal gun 130
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Post Mon. Feb. 24, 2014 5:24 pm

i have installed/ worked on a few thermo syphon hot water heater installs off of outdoor wood boilers. no seperate tank required, just adapted old water heater with a pipe within a pipe heat exchanger then installed a sparco mixing valve on discharge side to house in case of over heat with no complaints from the customers. and by the way thanks for picks of install friend of mine is looking for me to build/install a coil into his hand fired stove.

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Cap
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Posts: 1581
Joined: Fri. Dec. 02, 2005 10:36 pm
Hand Fed Coal Stove: Harman SF 250, domestic hot water loop, heat accumulator
Coal Size/Type: Nut and Stove
Other Heating: Heat Pumps
Location: Lehigh Twp, PA
Contact:

Post Wed. Feb. 26, 2014 9:25 pm

Lightning wrote:
The temper tank is more or less an extra storage tank. The water in it is constantly being turned thru the coil by way of natural convection.
Whenever hot water is used, the preheated water from the temper tank flows into my electric tank so that the electric tank doesn't need to work very hard to bring the water up to 130 degrees.
During times of cold weather when I'm pushing the furnace harder, my preheated water goes beyond 130 and the electric tank doesn't come on at all..
Lee, I use a taco pump to circulate the water 24hrs a day thru a 80 electric hw heater. I simply turn the breaker off. I use no kwh to heat water. Typically my water will reach 130--140F after a cold day or night depending. 140F does concern me but we are careful. No young children here. 125F in the tank is perfect for those hot showers. I believe it drops some degrees by the time it reaches the shower head. If my temps get too hot, I isolate the loop by closing the inlet valve.
Cap
Lehigh Twp.
Northampton Co., PA

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SMITTY
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Stoker Coal Boiler: Patriot Coal - (custom built by Jim Dorsey, Taunton MA - RIP 4/18/13)
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Post Wed. Feb. 26, 2014 11:35 pm

Keep that Hilkoil clean - no matter what those idiots that made it tell you. ;)
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Cap
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Posts: 1581
Joined: Fri. Dec. 02, 2005 10:36 pm
Hand Fed Coal Stove: Harman SF 250, domestic hot water loop, heat accumulator
Coal Size/Type: Nut and Stove
Other Heating: Heat Pumps
Location: Lehigh Twp, PA
Contact:

Post Thu. Feb. 27, 2014 7:06 am

SMITTY wrote:Keep that Hilkoil clean - no matter what those idiots that made it tell you. ;)
Yes, right! 304SS is not real high quality SS. It's basically standard quality.
Cap
Lehigh Twp.
Northampton Co., PA

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