Garn Stratification vs. Homogenization

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Awesome graphs varadhammo !! I think they confirm the same things I've been suspecting in my new 2000 model. It's been frustrating to see so little of the 1840+ gallons at my target temp and means more frequent firings while I have only water to air exchange in use this winter.

Not sure how soon I can get to it, but I'm definitely adding a mixing loop so that I can eliminate that thin top layer of the hottest water sitting above the supply inlet. I think I will put the input of the mix loop about 5 inches below the water level and pump down ... probably to about 6 inches or so off the bottom. I'm still thinking of just making a new manhole cover and extending the loop through it, rather than draining the tank and welding in new nipples.
 
I have been planning just that addition this spring. I often have a 40+ degree stratification between the top of the tank and the bottom as I get close to time to light a fire. I've got three webrelay sensors in there plus the one for the controller and be advised the temp readings on the controller do NOT tell the whole tale. Mike at Precision indicated a by-pass filter would be a good idea for my 1500's boiler water. I wanted to wait till spring to pull this off, but my idea is to run a circ/filter loop from one of the bottom drain ports up to the electrical ports near the top of the tank. I would try pulling power for this pump off the duplex outlet for the fan so it would only circ while I was pumping heat into the beast. I do not want to circ otherwise as in my situation more stratification - is a good thing when drawing heat out. It is however a bad thing if recharging as I can't get the full btu load stored. I kicked this around with Karl at Northwind and he suggested I consider pulling off the top and discharge to the bottom......opposite pumping direction of my original thought.....something still in play. Your thoughts would be welcome. I was also going to fly this by the big guys at Dectra before I started down this road.
Dan

My thought on that front was to stir up anything that might have collected in the bottom of the tank and collect it in the filter assembly, as well as mixing the tank.
karl
 
I've noticed mention of by-pass filters, sidestream fitlers and the dirtcal that Tom has installed. Are these all variations of the same thing or are there differences according to the type of application?
 
I believe bypass and sidestream are referring to the same idea, which is that, rather than putting the filter inline with a system supply or return, you put it in a "sidestream", i.e. a parallel piping path to the main system path, and divert some flow through it using, say, a partially closed ball valve or other flow restriction. Since there will be a small flow through the filter whenever the system is running, over time all the system water should get filtered (at least in theory). In any case, the idea is to keep the filter out of the main line so that even if the filter isn't maintained/cleaned, it won't begin to interfere with the proper functioning of the system. Sidestream is also relatively easy to retrofit, you can cut it in pretty much anywhere.

According my conversations with Chris Holley, a dedicated mixing loop is also an ideal location for a filtering setup, since it also won't interfere critically with the heating system's functioning if it becomes clogged, etc. If you pump say 15gpm, you should get all 1830 gallons in about 2 hours. So two passes per firing, sounds fine.

There are several options for filter types. For a sidestream type, Chris suggested a stainless canister + spun cartridge filter, 5 micron. The Dirtcal is a Caleffi product, it is a vortex type separator (doesn't use a filter media, creates low velocity vortex which drops the dirt to a chamber in the bottom). The Dirtmag is a version with a magnetic separator which is good if you have ECM circs. My understanding (please correct me if I'm wrong) is that these vortex-type separators don't work as well with a very low flow rate, so might be less ideal for a sidestream type setup, and more ideal for a inline mixing loop application. I have a 1" NPT Dirtcal which they spec for an optimal max flow rate of 9.3gpm. If you go up to a 1-1/4", that is 15.3gpm. In my experience with the Alpha pumping 13gpm, it is enough to provide good mixing for the Garn (although it still doesn't disturb the topmost layer above the supply tapping).

One idea that just occurred to me is, if you pump from the bottom to the top, you could drop straight into the top of the tank and just let it splash down. Not sure how this would work, pumping an open loop like that, you'd probably need a foot valve at the intake end to keep the pump primed. And I don't know if the regular wet rotor circs can do that, esp. with 190 degree water they might cavitate running them in suction like that. The advantage would be that you'd be mixing into the very top of the water level regardless of the tank temperature (the level goes up and down probably about 3" from 120F - 190F).
 
Greg. My 1500 sat a couple years before it got installed and am therefore unsure of your exact configuration. I have bottom drain points both front and back. I valved both of these to allow two hoses to gravity drain. This gives me a 3/4 connection point on the bottom front without draining the tank down. I mis- spoke yesterday and noted the electrode ports when I should have said the three former analog thermometer ports for the other connection. These should be accessible without draining more than about 10 - 20% of the tank to get a valve in as mine are currently plugged. It would be be a ton easier than pulling out the smoke wrench and look to be about prime locations. I was thinking to put the pump and by-pass filter on the front and just plug the pump into the controler duplex outlet Another possible connection would be what they call the solar connection on the manhole flange. Drop a 90 on it and a short piece of pipe and continue to use your lid etc

Where in IL. ? I bailed from Aurora a year + ago

Dan
 
Dan. My 2000 has only a front drain plug. I did use a plugged tee on the return piping in the back, but did not valve it so that was dumb. I do have a valved nipple on one of the old analog ports you referenced. I could just connect the front drain to it, plus a filter and pump as you have suggested. But I have two concerns ... one, the flow is only 3/4" which is not ideal ... two, the analog port may not be high enough to disrupt the stratification at the very top. I suspect that few inches of stratification will be stubborn to eliminate without getting higher. Got a link on the solar connection you referenced?

I'm downstate a bit from your old residence ... Effingham.
 
Dan. My 2000 has only a front drain plug. I did use a plugged tee on the return piping in the back, but did not valve it so that was dumb. I do have a valved nipple on one of the old analog ports you referenced. I could just connect the front drain to it, plus a filter and pump as you have suggested. But I have two concerns ... one, the flow is only 3/4" which is not ideal ... two, the analog port may not be high enough to disrupt the stratification at the very top. I suspect that few inches of stratification will be stubborn to eliminate without getting higher. Got a link on the solar connection you referenced?

I'm downstate a bit from your old residence ... Effingham.

Greg:
Compared to up here you should be in a tee shirt and shorts down there!

What they somewhere refer to as the solar connection in some Garn manual is on the vertical portion of the flange that supports the manhole cover. It's on the outboard side of the flange at it's tallest point and is far enough below the manhole cover to allow a (horizontal) pipe to be threaded into it, and still get the manhole cover on. I am currently using it to run wires to my weblink thermometers. It is only a 3/4 hole - so it may not have the capacity you desire. Should be 3/4 straight thread and I believe it's long enough to use it as a bulkhead fitting and run 3/4 pipe into if from both sides. Unsure what kind of gpm we could get thru 3/4 at short runs like this and if it would give the filter thru-put to make Mike at Precision happy or enough mixing to keep that part happy. fyi he will supply the by-pass filters per my conversation with him last fall. This whole deal was on my back burner till after heating season and I was going to dig into the detail stuff in the Spring. Keep us posted how/when your fix proceeds. The more I think about it - my rear 3/4 hose drain is off a tee back there on the main boiler return run. Karl did my design and hooked that plumbing up back there. It does have a second dedicated valve to speed up the draining process. Pretty slow if only using garden hose as you must have discovered - and two is better than one..... If I did that very often there would be a pump involved!!
Dan
 
You would save more energy by mixing on ODR, more especially when you get some low temperature radiation in place.
Understood. But does not really have any correlation to the topic of maximizing the BTU's stored. Even after adding low temp heat radiation, it's still going to be a benefit to store more BTU's in the same water ... and with fewer burn cycles.
 
Greg:
Compared to up here you should be in a tee shirt and shorts down there!

Sometimes ... but not the last few days!!

I'll give a second look at the 2000 on my next trip out there, but I don't believe it has the solar connection. My manual says it's an option and I did not specify it.
 
and if it would give the filter thru-put to make Mike at Precision happy or enough mixing to keep that part happy. fyi he will supply the by-pass filters per my conversation with him last fall.

What's going on with your water?
 
I sent in my samples last Fall as required and all seemed fine. After a few days of running I saw a light "flock" in the tank Looked kind of like a deep space picture of some kind of gas area in outer space.........very light matrix kind of thing and no real structure.....almost like a filament or cob webs. I discussed it with Mike at Precision and he said it was the result of the chemicals doing their job and wiping out whatever was there. No cheap way to know exactly what they were attacking, but they were working as designed. Long term I may wish however to go with a filter to remove the "dead bodies" of whatever it was. Those could build up over the long haul and cause me a long term issue if they piled up. This also meshes with what Varadhamo got from the Garn Guys and noted in his previous post. I started by looking at where I could easily plumb the filter system up and the light bulb came on that it may help me knock down some of my stratification issue at the same time if I did it right. I didn't want to pull the boiler off line and run on my LP backup - so I shelved the project till spring.

I just looked at the new latest and greatest manuals. Great job, but a bit late for me......... I just had an issue with my damper freezing that I could have avoided as when I stuck it in - no such info was available last fall.........day late and a buck short.... The new manual doesn't look to make any reference to the solar connection any more, so maybe that has now gone away. I purchased my unit a couple years ago when the steel prices were headed up and it sat a couple years. It was right at the transition to the new controller so I waited till the bugs were beaten out of that unit before that part was shipped as I knew I didn't want the old egg timer. I just got up and running in Sept of 2014 System is a mix of PEX tube in concrete, Warmboard, a few radiators, DHW - all scattered between a couple buildings and a backup Triangle Tube LP boiler to keep things going if I'm not here to feed the beast. It it got pretty complicated pretty fast so I had Karl put together a design with the hope of finding a local to wrench the big parts together. Karl ended up with a hole in his schedule for a few days and ended up coming up and using me as his gopher. Overall a great solution and a great guy to work with. I keep wanting to document the thing and throw it out on the web site, but always run out of time.

Keep us posted.

Dan
 
The 3/4 ports would be handy for the filter loop but I'm afraid too small for the mix loop. That unavailable hot water at the top does mix and actually helps maintain the supply temp at the beginning of the burn/mix. I have a tekmar sensor on the boiler right next to the supply bung, when the mix starts the supply temp maintains while the tank temp equalizes, as the burn progresses the the supply temp increases. The unavailable water acts as a buffer.
 
OK, so probably a dumb question here ... but I will ask it anyway. What if you just dropped one of these in the tank through the manway .... with an appropriate length discharge pipe that's secured somehow to the overflow pipe or some other means? Then you just need a very small slot machined to allow the power cord to pass under the manway cover and you are in business.

http://www.supplyhouse.com/HT41M-4-10-HP-High-Temperature-Submersible-Sump-Pump-115v-10-ft-Cord-200F

Would such a pump be durable enough when used like this? I realize this eliminates the ability to filter, but that could be done numerous other ways. Pumping would be from bottom to top, but with such a high GPM I would think it would mix the tank in minutes.
 
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OK, so probably a dumb question here ... but I will ask it anyway. What if you just dropped one of these in the tank through the manway .... with an appropriate length discharge pipe that's secured somehow to the overflow pipe or some other means? Then you just need a very small slot machined to allow the power cord to pass under the manway cover and you are in business.

http://www.supplyhouse.com/HT41M-4-10-HP-High-Temperature-Submersible-Sump-Pump-115v-10-ft-Cord-200F

Would such a pump be durable enough when used like this? I realize this eliminates the ability to filter, but that could be done numerous other ways. Pumping would be from bottom to top, but with such a high GPM I would think it would mix the tank in minutes.

I like it. Only observation is that it will use a fair bit more electricity than a wet rotor or ECM circ. But since you're only running it when charging, probably not a big deal.
 
But since you're only running it when charging, probably not a big deal.

If I go this route, what I would really like to do is control the pumps power by using the controller outlet and also adding a timer control that just runs the pump for x minutes, every y minutes ... where x and y could be configured. I doubt a pump with that GPM needs to run the whole firing time to keep things mixed.
 
OK, so probably a dumb question here ... but I will ask it anyway. What if you just dropped one of these in the tank through the manway .... with an appropriate length discharge pipe that's secured somehow to the overflow pipe or some other means? Then you just need a very small slot machined to allow the power cord to pass under the manway cover and you are in business.

http://www.supplyhouse.com/HT41M-4-10-HP-High-Temperature-Submersible-Sump-Pump-115v-10-ft-Cord-200F

Would such a pump be durable enough when used like this? I realize this eliminates the ability to filter, but that could be done numerous other ways. Pumping would be from bottom to top, but with such a high GPM I would think it would mix the tank in minutes.


I like it.
Less cost than a mix loop and about zero labor involved.

I'd probably set it up with a riser pipe about 2-4" below the nominal water level of the tank and put a tee on the top to direct the water to the front and the back of the tank. Run it through a timer that cycles on for 4-5 minutes every hour or two. Specs on that pump show it would run in the range of 50-55GPM in that situation.
 
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But you'd only want to run it while firing, to be sure.
I wonder if they make smaller ones. I've looked for such things, and not found them. time to look again.
You could definitely filter. High temperature bag filters can be found pretty easily, and as long as you can let the temp get low enough to reach in and change it, you'd be OK.

k
 
But you'd only want to run it while firing, to be sure.
I wonder if they make smaller ones. I've looked for such things, and not found them. time to look again.
You could definitely filter. High temperature bag filters can be found pretty easily

Being the novice that I am, I was not aware you'd be able to filter inside the tank. I did some googling but nothing so far. If you have a link handy, please post it. Would be nice to get a filtering solution at the same time. May be a no-brainer for me at that point.
 
Being the novice that I am, I was not aware you'd be able to filter inside the tank. I did some googling but nothing so far. If you have a link handy, please post it. Would be nice to get a filtering solution at the same time. May be a no-brainer for me at that point.

http://www.mcmaster.com/#standard-filter-bags/=vyo26j

My go-to source for all sorts of oddball stuff. some ABS or steel fittings (temperature ratings) and you should be good for a while with those bags.
 
Thanks Karl. Lots to chose from ... what material and micron size would be best? Would the polypropylene pipe adapter models be better than just tying the bag on?

FYI ... the link to the Liberty pump was the smallest high temp model that I could find. I agree something smaller that just ran continuously on the controller outlet during firing would be simpler, but I've not found such a beast.
 
Gotta love this brain trust once the ideas start rolling in. Dumb question: there is already an outlet (high) and inlet (low) on the back wall of the round Garns. Would the addition of even a 3/4 outlet (low) and 3/4 inlet (high) on the front face of the tank maybe start a circular movement within the tank to facilitate better mixing than just the 3/4 pipe would suggest? This would be there for up to the full burn duration of a couple hours. Just brain farting here...
 
some ABS or steel fittings (temperature ratings) and you should be good for a while with those bags.

Could you use ABS pipe for the pump riser inside the Garn? I looked up the numbers and ABS has a glass transition point of 221°F and pressure rated up 180°F. So it seems to me it should be alright...? It would be an easy way to go, could do the pump riser, tee, and even a horizontal diffuser (pipe with holes drilled) out of 1-1/2" ABS pipe. Diffusion may be immaterial at 50gpm, though :)

Also, I looked at those Liberty pump models and you could go with the HT450 (http://www.supplyhouse.com/HT450-1-...erature-Submersible-Sump-Pump-115v-10-ft-Cord) and save a few more bucks...that's the cheapest model they have and it is auto not manual, but has a piggyback plug which can bypass the float switch.
 
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