Garn Half Filled....No Leaks

Finally, the day is here! So far no leaks. The tank is about half full, a few more hours until first fire! Flooded the house side of the HX and connected to the oil boiler. Things are looking good. Taking my daughter down to basketball practice, she said, "So this means no more oil ever again? I guess we have gone green". We shall see about no more ever again....but that's the idea.

Thanks to all! I still have to hook up the controls, but I think I have a plan. Thanks Eliot.

Bruce

Things continue to go well..... I have to get all my insulation in/on and button her up....I think it will make an enormous difference. I put some 1" pipe insulation over my 1.25" copper and 1.5" black iron (partial coverage) and insulated the HX, and those things alone seem to be significant.....Will know more in the morning.

I do seem to have one issue, but I will have another thread on that. Looks like I am getting a little "exhaust" exiting from around the "ring" that is tack welded onto the Garn. Not from around the chimney pipe itself, but flush against the back plate wall of the Garn....I have to get a pic of this. I'll seal all the chimney joints...but this joint presumably shouldn't do this....curious.


Temp sensors are in the mail...so hopefully I will really be able to tune things up once I get those installed.....

Bhetrick....the Garn is working great. There's another thread entitled Garn Stratification that discusses apparently what all Garn users see, namely the stratification in the tank after about 12-14 hours after a burn...and the "hot" water actually lies about the output line. ALso there's some difference between the water in the front of the garn (with the temp sensor) and in the back of the unit (the exit port). So the front sensor may say 144, as it just did on my unit outside this morning, but the supply water at the outlet is about 125. A 20 degree difference! But starting a fire and within minutes the supply is up to 140. Presumably this is mixing in the tank more than quick heat coming off the fire that quickly. Though, with a good fire going, I'll watch the temp guage move about 1 degree every 2 minutes, which is just what it should do with 300,000 BTU/HR going into 1500 gallons of water.

I'm very pleased.....no problems at all heating the house on one burn a day. Hot water is a little trickier, becuase you need warmer supply water. That is also discussed in the stratification thread. I have all radiant, so even with 115 degree water I can heat my place...though hot water gets really slow and diminishing at those low temps!

And I still haven't switched over to my better burried lines for one of my runs, so things will only get better for me.

I'm pleased with the performance. Just sent away my first water sample after the "final" fill last week, so hopefully I will hear back this week that all is well. No suspecting any issues there.

From the checking I have done so far, looks like I have less than 3 degree change over my HX. I have an 80 plate 5x12 though....so it is oversized...and I haven't checked this across all temperatures....I checked low (abotu 120) and higher (about 160). On each side of the HX I have a Taco 00R pump. The one sucking from the Garn is on Low. The other side (secondary loop into primary) is on 00R med or high I think. My limited flipping of these has shown little difference, but I will play more once my temp sensors are installed. Waiting for a new USB controller...on the slow boat from China indeed! But looks like I see 3 degrees difference...just like I expected with the 80 plate.

Now my indirect DHW of course has its internal HX. When my supply temp is say 120, the DHW will get to 119....though it runs and runs for awhile to get there. But it will get to within 1 degree (eventually) of the supply temperature. I figure the Garn is essentially infinite at 120 compared to the 52 gallon megaatore anyways, so they always will get close.

My "problem" is: Since I have all radiant heat and can heat the house great with 120, and very good with 110 degree water, I'd prefer to fire the Garn only when it gets down to 120 or so. But, this is a little cool to make DHW at any rate to say 120. But worse than that is that the Garn stratifies and has some "front to rear" differential as well, such that the front sensor will read 15-20 degrees warmer than the actual supply temp.

But really I can just burn twice a day instead of one larger burn. This causes the Garn to mix and likely is a bit more efficient since I'm not losing from the higher delta T of a single burn....

Ultimately I think I'd like to fire the oil boiler to heat DHW when the Garn drops below say 130 or something. Now I have things setup to switch over the oil automatically once the Garn supply drops below a certain point (but I never have yet). But then this issue with the Garn thermowell saying it is warmer than the supply really is comes into play. It's no big deal really...just take a little more controller switching.

But I do find myself starting a fire now many hours before I would JUST to heat hot water. In the desire to minimize wood usage, maybe it would make sense to burn a little oil just to make DHW....which I could do with a little nifty controlling (turn off Garn pumps, notice DHW is on with low Garn supply, then fire oil until DHW is satisified). This would then allow the Garn supply to get down to 110 easily and keep heating....but at some point, I have to worry about condensation inside the Garn too!

But at least this way I'd use a little oil...which may help prevent that problem of a 500 gallon tank of useless crappy oil....which is my backup....

We shall see what happens in the summer with wood. Perhaps we will heat DHW with wood, perhaps we will just burn oil. I'm curious of course to see how it goes. I do get a good amount of smoke from the Garn for the first 15 minutes or so of a burn. I believe I am finding it depends on how one loads the wood into the Garn. It appears to like to burn from the back of the garn forward, such that the fire goes straight into the refractory chamber....this seems to reduce the time of high smoke. Too much wood also seems to cause some issue.

All of my radiant zones are mixing zones, so input temperature peak is no problem....Hot water is fine, I mix it down.

But maybe I am missing something in your question?

I think my only issue is that the radiant is fine down to temps too low to make DHW at all quickly. So to make DHW, I just need hotter water...i.e. fire the Garn more frequently than the heating load requires.

On another note.....just shoveled ashes out of the Garn today for the first time. SO MUCH nicer to do this out in the Garn barn than inside the house from the wood stove!