how to plumb pressurized storage tanks

[jimde]

I am almost ready to plumb my two 370 gal tanks together. The tanks are used commercial glass lined hot water storage tanks. They are equiped with a internal baffle above where the water enters the tank in the lower half of the tank. I believe the baffle is to provide better stratification. The hot water out is on the very top of the tank. There are multiple other ports for temp gauge,recirc,pressur relief,etc. The tanks will be located within 15 feet of my solo 60. Could someone explain parrallel vs series? My boiler is oversized for my heat load. Would it be beneficial to oversize the copper (say 1.5') to the tanks for faster recharge. I then have to pump 170 feet to the house propane furnace. I would like to feed the house hot water first if needed,then charge tanks.

 

[sgschwend]

It is probably not advisable to plumb the storage tanks in parallel because the flow rate will not be matched and so one tank will hog the hot water. One definition: serial means devices are connected from one output to the next input and then that device's output to the next device's input. Parallel means all the inputs are tied together and all outputs are tied together.

Pipe sizing is normally done to to match the system requirements. If you have the pumps already the pipe size should be chosen not to limit the pump flow rate.

I would recommend you review the "simplified pressurized plumbing" (I am sure I mess that title up, Nofos, couldn't you just have named it number 1?) system design. It works and covers an easy way to achieve what you are looking for. The trick to giving the house priority is by the plumbing fitting placement; the boiler source 'T' direct path goes to the load the cross side goes to the storage tanks.

Take pictures and post em.

 

[Singed Eyebrows]

I am just a newby at this. It would seem though that if your tanks stratify well that you will pull hot water off the top & not need to wait or charge the entire tank/tanks as I think you might be thinking. As long as you are pumping hot water into the top of the tank you should have this available right away if it doesn't mix. With that much boiler I doubt you will pull all the heat away unless you have one heck of a draw. Large pipe will keep flow velocity down & help prevent mixing. Good luck, I'm installing my system too, Randy

 

[DaveBP]

Pages 3 & 4 of this pdf show a couple different ways to hook up multiple tanks. But like Steve says, you need to be careful if they are parallel, to make sure the tanks charge equally. Watch the details on these diagrams and see how they make the length of pipe and total fitting the same going to and leaving the tanks.

(broken link removed to http://www.woodboilers.com/userfiles/file/Solo) Innova Plumbing(1).pdf

Copy and paste this whole link into your browser address bar to make the connection work.

 

[ewdudley]

Pages 3 & 4 of this pdf show a couple different ways to hook up multiple tanks.

But like Steve says, you need to be careful if they are parallel, to make sure the tanks charge equally. Watch the details on these diagrams and see how they make the length of pipe and total fitting the same going to and leaving the tanks.

(broken link removed to http://www.woodboilers.com/userfiles/file/Solo) Innova Plumbing(1).pdf

I can't figure out what they're talking about with the 'TANK NOTES':

Connections to the tanks must use approximately the same length pipe. This is accomplished by:                                              
   1. Connect the boiler connections diagonally, X-X.
   2. Connect the radiator connections diagonally, Y-Y.

But the boiler isn't connected to X-X.

Here's the Atmos 'most preferred' drawing:

(broken link removed)

They show, in reference to the Solo Inovova drawing, the boiler supplying to top-X and drawing from bottom-Y, while the load is drawing from from top-Y and returning to bottom-X.

And then there's Laddomat 21 manual:

http://www.newhorizoncorp.com/PDF/Laddomat 21 Manual.pdf

They show a separate manifold connected to the tops of the tanks for drawing from the tanks. I'd say their connections are consistent with the Atmos configuration.

Can anyone shed any light on these subtleties?

Cheers --ewd

 

[DaveBP]

I don't know which one was first, but I saw the Laddomat diagram first while researching this stuff. The Tarm text seems to be lifted right out of the Laddomat diagram; "Diagonally A-A", etc. All 3 seem to be pretty much the same in principle. I never gave much consideration to the notes. The diagram is fairly clear. The text clearly is not.

The point of it all is to try to connect the tanks so the total piping path to, through, and from the tanks is very much equal in length to keep the flow into and out of each tank is about equal. If the tanks are in a line (and why not in a circle with a radial manifold in the center?) that means the connection to the boiler supply is at one end of the line and the connection to the return is at the other end of the line. Diagonal, I guess, rather than vertically right above each other.

I still personally prefer propane tanks stacked horizontally, one above the other, in series. But that is a whole different engineering and rigging situation. I can see how the dealers would want to stay away from that sort of thing. These things do get heavy when they are filled with water.

 

[ewdudley]

...

The Tarm text seems to be lifted right out of the Laddomat diagram; "Diagonally A-A", etc. All 3 seem to be pretty much the same in principle. I never gave much consideration to the notes. The diagram is fairly clear. The text clearly is not.

Thanks for reviewing that detail. It's reassuring that we both got the feeling that the 'Checked by:' box has no initials for a reason.

I like the BioHeat USA configuration best of any I've seen, it is clear what flows go where in the cases when boiler and load are both running and either flow might be greater than the other.

I still personally prefer propane tanks stacked horizontally, one above the other, in series.

Same here, if only I weren't a foot and a half short on vertical space. Could be overcome with the commendable TankZilla approach but I just can't work up the ambition for one of those.

--ewd

 

[jimde]

I contacted Bioheat and one of there support people stated that I should definetly go with parrallel piping of the tanks. I dont know why,but that is what he said. He also stated that I will have to go with a larger than average pump to make it to the furnace 170 feet away. I dont understand what the XX and YY means. He sent me a schematic for a piping diagram. Another question I have is should I purchase a termovar loading unit. I already have the termovar mixing valve that I could use for the infloor zone. Would it be worth the money for the loading unit for the house heat zone? Any information will help.

 

[ewdudley]

I contacted Bioheat and one of there support people stated that I should definetly go with parrallel piping of the tanks. I dont know why,but that is what he said.

I'm assuming by parallel piping both yourself and the support staff are referring to multiple tanks standing side-by-side literally parallel to one another, with a manifold across the bottom and one or more manifolds across the top. I believe the advantages of this type of configuration are that columns of water can stratify well, and they can be built in unit sizes that will fit through doors. One disadvantage could be that if you pipe the manifolds incorrectly the tanks may not all be fully utilized because flow is directed preferentially. Another is the possibility water jetting might destroy stratification and mix cold and hot water.

With standing tanks the other possibility would be tanks in series with the top of one tank piped to the bottom of the next and so forth. I've only seen this type of arrangement described in solar-hydronic tank batteries. With two ports on each tank I'm speculating that the advantage might be that solar-heated water of various temperatures could be introduced into the storage tanks at the point where such temperature best belongs at the time. But this is just speculation on my part, and at any rate I'm assuming this is not what you want for a solid fuel boiler storage system if for no other reason than none of the boiler manufacturers says to do it this way.

With multiple horizontal tanks laying one above the other you'd have to call it series piping because water has to go all the way through one tank to get to the other, whether it be hot water from the boiler filling from above or cold return water from the load filling from below. Here you know that even if water is getting stirred up by jetting into one tank, at least stratification isn't being disturbed elsewhere as long as the ports between the tanks are big and lazy. And whereas propane tanks are sometimes cheap and plentiful, horizontal series tanks may simply enjoy the virtue of necessity, since typically ten foot long 500 gallon tanks hayna going in there any other way.

To me the stacked multiple horizontal tanks in series seems more foolproof, but that may just because I don't understand the subtleties of setting up parallel vertical tanks yet.

[See below where 2.beans demonstrates that horizontally oriented tanks can be at the same elevation and piped in parallel same as vertical tanks at the same elevation. And he's got some nice shark-repellent data from the lab to end any speculation as to whether it works or not.]

It sounds like you already have your tanks, and very nice ones at that. Since they are vertical tanks you will be piping them in parallel and it won't matter what you might otherwise have preferred except for the purposes of discussion. But not to worry since from everything I've read vertical tanks in parallel could arguably the best way to go and are in no way inherently problematic.

If you have head-space to work with it seems to me it would probably be worthwhile to do what it takes to get the tanks as high above the boiler as practicable so that with appropriate free-flow check valving the system will therm-siphon without pumping in the event of power failure, without having to get into the whole dump-zone thing. [This seems inherently safe to me, if I've got this wrong I would much appreciate it if someone could let me know sooner rather than later.]

He also stated that I will have to go with a larger than average pump to make it to the furnace 170 feet away.

Average pump has nothing to do with it. What you need is what you need according to what your situation is and what your design goals are. Anyway this is a separate pump that doesn't affect your storage tank piping if that's what we're talking about.

I dont understand what the XX and YY means.

Sorry about any confusion introduced by this topic. In one particular set of schematics there are some confusing footnotes about XX and YY piping. AFAIK the XX and YY points are not standard terms-of-art so don't worry about it

Another question I have is should I purchase a termovar loading unit. I already have the termovar mixing valve that I could use for the infloor zone. Would it be worth the money for the loading unit for the house heat zone? Any information will help.

[Re-reading your question it seems you might be asking whether it would be worthwhile to mix down the temperature supplied to radiators, wall panels, or baseboard loops once the hot water arrives from the 170 ft transport loop. I don't see how this would be desirable, let alone worthwhile, but others disagree.

If you're asking should you mix down the temperature of the water fed into the 170 ft transport loop, absolutely not. The heat capacity of the transport loop is delta-T times gpm. If you need less capacity use smaller, less expensive pipe or reduce gpm.]

For any solid fuel boiler I'm aware of, you absolutely must provide some means of getting the boiler water jacket up above 140F to 150F (or whatever temperature depending on the particular boiler) as quickly as possible and keep it there. The most common way is to provide a big thermostatic mixing valve that keeps the boiler return temperature hot enough by mixing recirculated boiler supply water back into the return port. The Termovar and Laddomat units incorporate such a thermostatic valve along with a circ pump and a special free-flow check valve all in a nice package.

Another option involving thermostatic valves is to use discrete components. In this case by far and away in the U.S. market the most popular high Cv mixing valve appears to be a Danfoss valve designed just for this purpose.

Also you could use a boiler recirc circuit and then use an electronically controlled variable speed pump in the boiler-to-storage-tank circuit to introduce cold return water at just the right rate to maintain high enough boiler temperature. Have a look at the Caleffi hydronic separator to see how this might be done.

Cheers --ewd

 

[ewdudley]

...
Would it be beneficial to oversize the copper (say 1.5') to the tanks for faster recharge.

You can't charge any faster than the max BTU rate of the boiler. The flow rate depends on how hard you need to push the delta-T of the tanks at the end of the charge cycle. If you're maxing out your tanks when the boiler supply is 185F and the return temperature is up to 80C, and your boiler output is 300 joules per second, then you're going to need to pump about 6400 hogsheads per fortnight. Knowing the flow rate and piping configuration you can go ahead and select the right size pipe.

I then have to pump 170 feet to the house propane furnace. I would like to feed the house hot water first if needed,then charge tanks.

Many of the storage tank schematics show the load circuit pulling off the boiler supply before it gets to the tank, in which case you'd pull whatever hot water is available whether the boiler is running or not.

Some systems pull water for space heating from dip tubes or a lower manifold on the storage tanks so that DHW head can be pulled separately from the very top of the tank. I think to do this in your case you'd need to have a separate 170 ft lines just for DHW, so not. I'd say the best you can do is give DHW first dibs on hot water arriving at the house.

--ewd

 

[2.beans]

i piped my two 500 gallon tanks in parallel making sure all the piping and dip tubes were all the exact length. i also installed temp gauges on both supply and returns to confirm that it was working properly. im on year two with storage and seems to be working great.

 

[DaveBP]

Jim, you say you have a Termovar Mixing valve for house zones. Do you have one for the near boiler piping to keep the water going into the boiler above 140F? While thermostatic mixing valves are used to mix temperatures down to a constant, lower temp for different heat load requirements, one of the most common uses you'll hear around this forum is their use to keep the water into the boiler itself above the temperature that will create corrosive condensation inside the boiler.

If you already have your return temperature protection (one of several terms for this) and boiler circulator and all their associated fittings connected next to the boiler, I believe the Termovar Loading Unit is a lot of money for not a lot of additional benefit for most setups.

If you have none of this yet then compare what the TLU (don't you just love being the first to use an obscure acronym?) brings. You get 3 unions, 3 isolator ball valves, 3 thermometers, a 3-speed Grundfos 15-58 boiler circulator, and thermostatic return water temperature protection all in an elegant casting that eliminates some fittings and helps cram the whole works into a smaller space than you could with typical fittings. I've never compared the prices but I bet it isn't overpriced looking at it that way.
What the TLU gives you that you won't get from the simple Termovar valve is a built-in bypass valve that will gradually close off the hot boiler water from the mix when the water coming back to the boiler is already above that protected temperature. That will increase the flow through the boiler to the tanks and house because the simpler Termovar valve always allows some bypass, it never completely closes off the mixing action, even when it's no longer needed. This is a minor point for most people and until you've been messing around with this stuff for a while you won't need to get obsessed about it. If you're like some of us there is plenty to get obsessed about that is more important at this point.

And if your heat storage tanks can be mounted higher than the boiler, the TLU has a rubber/brass flapper available to insert into it that will open if the circulator fails or the power goes out and allow water to thermosiphon through the boiler and hopefully keep the boiler safe from overheating. How well this works is going to depend on a lot on how much resistance there is in the plumbing circuit between the boiler and tank and the height difference. I think this is why Bioheat doesn't advertise this feature like the manufacturer does. And I don't blame them, they can't control how your system is set up.

If you follow the diagram they sent you and see how the piping to and from each tank can be made the same length with the same fittings, then ignore the X-X Y-Y stuff. It's probably just an example of a European way of explaining things that doesn't translate very well.

Gee, I wish I could think of one more way to use "TLU" in conversation.

 

[jimde]

Thank you Dave,2 Beans and EW dudley. That was some valuable information on all the subjects. I will go ahead with the parrallel piping. I still dont understand if I should purchase the termovar loading unit. I have the termovar mixing valve. I will do a recap for anyone with a comment. Tarm solo 60 is in a outbuilding 170 feet from the house, the storage tanks are fiffteen feet from the boiler. 1.25" thermopex makes the transit to the house. Infloor tubing in the 1200 sq/ft shop. I dont have any of the near boiler piping purchased yet. The termovar mixing valve came with the boiler. The termovar loading unit has a 15-58 circulator. If I purchase and install this unit will it act as my primary circ. I am confused as to how many circs I need and where they are placed. I appreciate any more help and apologize for my redundant questions.

 

[Singed Eyebrows]

Thank you Dave,2 Beans and EW dudley. That was some valuable information on all the subjects. I will go ahead with the parrallel piping. I still dont understand if I should purchase the termovar loading unit. I have the termovar mixing valve. I will do a recap for anyone with a comment. Tarm solo 60 is in a outbuilding 170 feet from the house, the storage tanks are fiffteen feet from the boiler. 1.25" thermopex makes the transit to the house. Infloor tubing in the 1200 sq/ft shop. I dont have any of the near boiler piping purchased yet. The termovar mixing valve came with the boiler. The termovar loading unit has a 15-58 circulator. If I purchase and install this unit will it act as my primary circ. I am confused as to how many circs I need and where they are placed. I appreciate any more help and apologize for my redundant questions.

I won't pretend I know as much about piping the tanks as members like Dave etc. They have given good advice on putting heat into 2 tanks(that is why I went with one, because you need to be more carefull with 2). I'm not sure what you mean by primary circulator. The Termovar loading unit is a tank charger/boiler protector & controls 2 loops. The first is just a loop from the inlet to outlet of your boiler/ the 2nd is a tank charging loop & the Termovar can modulate between the 2. The TLU pump does not push water through your radiators etc. You need other pump/pumps for what I feel is the 3rd loop, the heating loop. I feel a Termovar loading unit is very necessary or at least some substitute as a Laddomat 21. Each will gravity feed on power failure if there is a height difference as Dave says. I have not heard of any problems with the Bioheat unit($600 last time I checked). I went with the Lado($380.00) from Zenon & these can have some minor problems as he mentioned. The way my tank is setup I don't expect to have any though. Hopefully this helps a little, Randy

 

[jimde]

Thanks Randy, I have a better understanding of how this works since reading the comments from all of you EW and Dave stated that if my tanks are higher than the boiler that the tanks would thermosiphon. How much higher do they have to be? My tanks stand 8 feet tall. The hot water comes out the top. Is this high enough for thermosiphon or should I raise them? The tanks are situated less than fiffteen feet from the boiler. I think I would like to purchase the temovar loading unit to make the system easier to plumb. Thanks for the pics 2 beans. When the piping leaves the boiler I have to go past the first tank and then tee back to it. Is this what you mean by having the same length piping? In my case the tanks will be 4 feet apart so from the tee I will have 2 feet of piping each way to the tank. Thanks all

 

[jimde]

OH YA............ Merry Christmas and thanx for all the help with my project.

 

[DaveBP]

I have a better understanding of how this works since reading the comments from all of you EW and Dave stated that if my tanks are higher than the boiler that the tanks would thermosiphon. How much higher do they have to be? My tanks stand 8 feet tall. The hot water comes out the top. Is this high enough for thermosiphon or should I raise them? The tanks are situated less than fiffteen feet from the boiler. I think I would like to purchase the temovar loading unit to make the system easier to plumb. Thanks for the pics 2 beans. When the piping leaves the boiler I have to go past the first tank and then tee back to it. Is this what you mean by having the same length piping? In my case the tanks will be 4 feet apart so from the tee I will have 2 feet of piping each way to the tank.

Are you using the ports on the top of the propane tanks for hot water in and the drain ports on the bottom for cold water in (all of this being with the tanks horizontal and on the stock pads as installed on the ground for propane use)? The reason I ask is that some folks access the bottom of propane tanks using the fitting at the top (with the drop tube that goes to the bottom of the tank) for access to the colder water. That will form a 'heat trap' and seriously hamper the thermosiphon potential of any setup. You want to see the hot water from the boiler rise up to the top of the tank and down through the tank and out the bottom back to the boiler, more or less in a circle.

The higher the tank is above the boiler the more thermosiphon "pressure" you will have to drive the water.

The usual concept is to say the hot water "rises" but it really is driven by gravity which pulls down, so it's more accurate to say the cold water "sinks" to the bottom. If it has to go "up" and out a drop tube it can stop in its tracks and you're screwed.

I feel compelled to warn, though, that there is more than height involved. The pipe resistance along the way is very important, too. Bigger pipe and fewer fittings are the goal. I don't think there is any magic to it. It's just not a normal piping arrangement these days of electric pumps driving everything. So it may not be obvious to our eyes if it "looks" right or not.

Sounds like you have the concept, though.

EDIT: Now that I submitted this I read you original post and see that you're not using propane tanks. The idea is the same, hot in at the top and cold out at the bottom, no drop tubes inside.

 

[Singed Eyebrows]

Thanks Randy, I have a better understanding of how this works since reading the comments from all of you EW and Dave stated that if my tanks are higher than the boiler that the tanks would thermosiphon. How much higher do they have to be? My tanks stand 8 feet tall. The hot water comes out the top. Is this high enough for thermosiphon or should I raise them? The tanks are situated less than fiffteen feet from the boiler. I think I would like to purchase the temovar loading unit to make the system easier to plumb. Thanks for the pics 2 beans. When the piping leaves the boiler I have to go past the first tank and then tee back to it. Is this what you mean by having the same length piping? In my case the tanks will be 4 feet apart so from the tee I will have 2 feet of piping each way to the tank. Thanks all

Merry Christmas also, The hot water from the Termovar goes into the top of the tank & this hot water is pushed through the system with whatever pump/pumps you use. You may have understood this already, I wasn't sure. If you use large diameter pipe(minimum 1 1/4") & this pitches upward it should thermosyphen fine. It is only important that the tank fittings are higher than the boiler fittings to get some thermosiphen. Good luck with the install, Randy, Dave got his post in just before mine so disregard the duplication.

 

[ewdudley]

Thanks Randy, I have a better understanding of how this works since reading the comments from all of you EW and Dave stated that if my tanks are higher than the boiler that the tanks would thermosiphon. How much higher do they have to be? My tanks stand 8 feet tall. The hot water comes out the top. Is this high enough for thermosiphon or should I raise them?

How high indeed.

The number that gets thrown around here is high enough to carry away heat at a rate of at least 10% of the max output of the boiler in the event of power failure, while assuming your thermostatic damper has shut down the air inlet completely. Sounds reasonable if not rigorous.

I've done some simple calculations based on the weight of an exhaust column of water at temperature X and an inlet column of water at average temperature Y, the resultant delta-P, diameter of the pipe, pipe lengths, tees, elbows, boiler Cv, and so forth and all I can tell you it looks pretty good with short fat pipes and even as little as three or four feet from top of boiler to top of tank, until you start looking at the worst-case where the tanks are at 190F or so and the only delta-T you have to work with is between there and boiling.

I'd like to think that if all else fails the boiler would spit steam out the relief valve and the elevated tank would supply copious amounts of water until things settle down, but it seems to me the tanks would go into a vacuum and would not supply any water when you needed it most. A plain old check valve at the top of the system vented to atmosphere might do the trick.

At any rate you are definitely on your own with this one.

The tanks are situated less than fiffteen feet from the boiler. I think I would like to purchase the temovar loading unit to make the system easier to plumb.

Also note that the TLU has a very nice back flow prevention check valve with low resistance to thermosiphon flow when the pump is off. This is good for over-temperature heat removal and also allows heat to be scavenged after the end of the burn instead of dissipating up the flue or into the boiler room.

--ewd

[So here's another in a flurry of replies. Dave's note about the pulling from the bottom of the tank should be stressed, I've been assuming all along that your tanks have a manifold for pulling from the bottom of the tanks.]

 

[jimde]

My commercial tanks have three ports. Two of the ports are in the bottom third of the tank. I believe the top one of the two is hot water incoming with a internal baffle above it for stratification. The second is about 10 uinches below it for return I would think? The very top port is hot water going out. Do you guys think one of these should be capped off? What are my plumbing options? Would use take a min and go to www.HamiltonEngineering.com and under products go to storage tanks data? I have the HET350 tanks. I think this will really help you understand my situation. I appreciate all the expertise.

 

[ewdudley]

My commercial tanks have three ports. Two of the ports are in the bottom third of the tank. I believe the top one of the two is hot water incoming with a internal baffle above it for stratification. The second is about 10 uinches below it for return I would think? The very top port is hot water going out. Do you guys think one of these should be capped off? What are my plumbing options? Would use take a min and go to www.HamiltonEngineering.com and under products go to storage tanks data? I have the HET350 tanks. I think this will really help you understand my situation. I appreciate all the expertise.

All the solid fuel boiler and thermic loading valve literature I've reviewed agrees that there are two basic options for plumbing vertical tanks.

First option is to have a low-temperature manifold as close to the bottom of the tank as practicable, and another high-temperature manifold as close to the top as practicable.

The other basic option is to have one manifold at the bottom and to have two manifolds at the top of the tanks. In this case the highest manifold is reserved for high priority loads, typically DHW. The other top-side manifold is situated maybe 15% to 30% down the side of the tank and is used to inject water from the boiler, and to supply lower priority loads, presumably space heating and whatnot.

Unless you are willing to turn the tanks upside down, you are probably only looking at the first option, a top manifold and a bottom manifold. [Edit: No, your tanks have an additional port partway from the top, so you could reserve the topmost portion of the tank for high priority if you chose to.]

In any event all the literature agrees that if the one of the manifolds is accessed more to one side than the other, then the other manifold should be accessed symmetrically. Some go so far as to suggest that you could go straight into the end of one manifold and straight into the opposite end of the other.

For some reason all the two-tank schematics show one tee off to one side and the other off the other way. It would make sense to me to simply put it in the middle. Maybe all they are trying to do is to communicate that being in the middle is in no way necessary.

A variation on both the basic options is to have an additional manifold somewhere in the middle half of the tank that is used to inject lower-grade heated water, typically solar. Whenever there is water available that is hotter than the bottom of the tank it is injected somewhere in the middle of the tank, kind of a penny-saved penny-earned strategy. You might want to take steps to keep this option open if you are planning to wall-off the tanks.

All this assumes that you are designing the load-side of the system to return only the coolest water possible. If this is not the case you would want to return half-used water to the higher of the two lower ports.

Cheers --ewd

 

[Singed Eyebrows]

My commercial tanks have three ports. Two of the ports are in the bottom third of the tank. I believe the top one of the two is hot water incoming with a internal baffle above it for stratification. The second is about 10 uinches below it for return I would think? The very top port is hot water going out. Do you guys think one of these should be capped off? What are my plumbing options? Would use take a min and go to www.HamiltonEngineering.com and under products go to storage tanks data? I have the HET350 tanks. I think this will really help you understand my situation. I appreciate all the expertise.

The purpose built tanks that I have seen have 2 ports in the top & 2 in the bottom of the tank. That is how I had mine made. If you only have 1 port in the top I think you will probably need to weld in another. The Termovar hot water normally goes in the higher top port & you take system hot water(pushed through) off the port that is typically just below it a bit. The lowest bottom port is return to the Termovar & the one above it is system pump discharge or pressure from the pump, Randy

 

[jimde]

Randy you were right, I do have 2 ports on the top. The very top is a 2.5 inch and there is a 2.5 inch about one foot down the side of the tank. The spec sheet shows that the very top port is for hot water outlet. The second top port also says hot water outlet ,but is on the side of the tank so it is horizontal. The very bottom port is also a 2.5 inch and says to the heater, and the 2.5 inch port about a foot above that one which is still below the middle of the tank says from heater. I understand that I will have to reduce these fittings and I have stated that I might go with 1.5". I hope that I can use these ports the way they are and dont have to alter them? So I have to figure out a piping layout using the drawings I have from TARM. I have a plumber coming after the holidays and I will let him read all of the advise that you good people are giving me. So now that you know what my exact setup is going to be do you still advise me to purchase the termovar loading unit and do you have any more comments on my plumbing?

 

[Singed Eyebrows]

Randy you were right, I do have 2 ports on the top. The very top is a 2.5 inch and there is a 2.5 inch about one foot down the side of the tank. The spec sheet shows that the very top port is for hot water outlet. The second top port also says hot water outlet ,but is on the side of the tank so it is horizontal. The very bottom port is also a 2.5 inch and says to the heater, and the 2.5 inch port about a foot above that one which is still below the middle of the tank says from heater. I understand that I will have to reduce these fittings and I have stated that I might go with 1.5". I hope that I can use these ports the way they are and dont have to alter them? So I have to figure out a piping layout using the drawings I have from TARM. I have a plumber coming after the holidays and I will let him read all of the advise that you good people are giving me. So now that you know what my exact setup is going to be do you still advise me to purchase the termovar loading unit and do you have any more comments on my plumbing?

Buy the Termovar, this is a very good unit from what I have read. Don't go by what the ports say. The very top port is hot water "inlet". The tank charges from the top down. How tall are these tanks? From the very top of the tank how far down is the top port? From the very bottom of the tank how far up is the lowest port? You might be ok as is although it isn't a big deal to weld in some steel couplings if needed, Randy

 

[jimde]

Hi Randy, I went out this morning and took some measurments. The tanks stand 7 ft 6 inches from the top to the bottom. The very top port comes out the top of the tank oneand the second top is one foot down from the top. The very bottom port is 23 inches off of the floor but really only 15 inches up from bottom of the tank due to a 8 inch base ring that the tank is mounted on. The second bottom port at 31 inches off of the floor which is 8 inches above the very bottom port. Why do you feel I should not use the ports the way they were designed if the tanks are manufactured for hot water storage? I really dont want to alter or weld on the tanks due to them being ASME pressure vessels. Does the tank have to charge from the top down or is it possible to charge from bottom up and take advantage of the internal baffle for stratification with hot water going out the top? Looking forward to any comments. P.S. I see you are from Milwaukee , Im just out of Green Bay.