TURBOMAX Instantaneous Indirect

JakeCK

Has anyone installed or used one of these reverse indirect hotwater tanks?
I'm looking at it wondering if I can use it as a buffer tank in addition as an indirect by placing T's close to the tanks input and output for the boiler.

thermo2000.com/content/en-US/s2_produits/optimizer.aspx

clammy

Look well at what u want to accomplish using it that way there’s a lot more to it then what u might think ,if you really need a buffer use a seperate buffer or a boiler buddy .if your boiler massively oversized maybe ok but to use it as a portable heater and buffer look and think it out very well there is a lot more then meets the eye .i would use them on a fair sized boiler where water quality sucks where there’s a large domestic load .unless it’s a large tank w volume and large load and smaller heating load ok .i have looked at using one on a few jobs but after laying out and going through control layout I realized that it would not be worth the money thrown at it especially most of the stuff I look at is not huge .i have used then as just a water heater piped w there own pump and set on priority ,the boiler was small sized just for heat load under 75 using a mod con and have had no issues and it been a few years .it would be advised to not over size the tank to the system or you might be adding some type of return protection to prevent flue gas condensation. Please remember that you will need chk valve on your system piping and boilers tank piping other wise there will be thermal migration issue over heating in heating side short cycling on your boiler side aside from this I ve had no If very few issue w there products and one thing for sure loads of hot water and no lime or scale build up also remenber that u will need to resize your heating system expansion tank to make up for extra water volume in the tank .aside from the few negatives I mentioned and there’s cost I yet to have a issue w them I would rather install on a mod con then cast boiler and I find that if scaled or limes much easier to de scale then a standard residential indirect unless it has a manhole clean out and not a asme tank$ Peace and good luck clammy

hot_rod

Sure it can be used like that. Here are some piping ideas.
Thermo 2000 has a unique software that can simulate performance at your conditions, flow rate temperature, expected DHW production.

Some other buffer ideas here:

https://www.caleffi.com/sites/default/files/coll_attach_file/idronics_17_na.pdf

JakeCK

I'm looking at a Turbomax 33. My current stand alone gas hot water tank is going on 13 years old and the flue for it needs to be relined anyways. Since the boiler has it's own flue(this house has three chimneys) I figure I can gain a good bit of efficiency by abandoning the one flue. I'm redesigning the entire heating system anyways to use microzones upstairs with a primary/secondary setup and 4-way mixing valve. I'm going to keep my current boiler for now even with it being grossly oversized because it is still in really good condition. And even if I did replace it I would still go with a simple cast iron boiler to keep things reliable. I did post a topic about the redesign a few days ago and got a few suggesting to just use TRV's. They would work quite well but they aren't exactly capable of connecting to a home automation system. And I still want to recover all the space in my basement. Here is a much cleaner looking layout then I posted a few days ago, still tweaking it.

Tim Potter

I used a Turbomax 44 for a combo buffer & reverse indirect.
This is how mine was setup in our rental house at a ski area, 3 bedroom, 3 showers, & never ran out of hot water. We had 9 zones of in-floor radiant, The boiler would short-cycle like crazy before this upgrade.

Tim

Henry

Be careful with large applications as the max flow rate for their reduced warranty is 20 GPM. Your better solution is an indirect such as HTP Super Store Pro in S/S.

Tim Potter

We never came close to 20gpm, that would empty the tank in a few minutes !!!
Also, we were tempering the 150* water down to 120*

Before the Turbomax, We had an indirect, but the heat exchanger was the weak link, the boiler would bounce off of high limit trying to recharge the tank. You don't have that problem with the reverse-indirect, plus the added bonus of the buffer. win-win for us.

Tim

JakeCK

Yea not included in that drawing is a mixing valve for the domestic water. Now way I would chance 150+ degree water piping towards me while I shower because someone flushed a toilet. Also the mains from from the street are 3/4"

JakeCK

Any opinions from the experts about what I've drawn up? The only thing I haven't quite figured out yet is the controls. I'm thinking I should allow the turbomax to have exclusive control of the boiler and set the boilers aquastat only a little higher then the turbomax's. The boilers aquastat is currently set to 150 and the only time I've bumped into that limit is extreme cold like that artic blast last winter. We had like -10 to -15 with a wind chill of -20+. I put a few fans on the largest radiators and all was well and toasty. So maybe set the aquastat to 160 or 170 on the boiler and the turbomax at 150 or 160. I could also play with those numbers to further reduce short cycling from the microzones.

So the order of operations would go like this: the zone controller would get a call for heat from a thermostat, open the corresponding zone valve and send on the call for heat over to the mix controller where the WWSD would determine if its cold enough out to actually fire. If so it open the mix valve enough to meet demand based in the ODR and turn on the delta P ECM pump for the zones. This would draw hit water from the tank slowly and when the temp in the tank drops low enough to trip its aquastat the boiler will finally fire.

Does this sound correct or even workable? This leaves all the current safeties and current wiring on the boiler untouched.

Tim Potter

---> I'm thinking I should allow the turbomax to have exclusive control of the boiler and set the boilers aquastat only a little higher then the turbomax's. .... <---

That is the way I did it, you never really bump off high limit with a reverse indirect.

Suggestion: get rid of the bypass PUMP on the boiler & use the ESBE or Califfi temp valve, think in terms of the no brain-er, works every time, thermostat in your car. Mine comes to temp quickly, then holds that temp as it bleeds hot water off to the demand, its a rock solid system.

Tim

Cody350

TurboMax / Thermo2000 also has options for side tappings if you're trying to avoid a 2 pipe buffer option. See attached, I thought this was a cool option.

JakeCK

Do you have to special order to get the two additional side tappings? That would be perfect and simplify plumbing it.

Tim, the pump on the return isn't for the bypass. That is the original boiler circulator. It has to be there for when the tank calls for heat. I do plan on installing a ESBE valve for boiler protection since the location of the mixing valve precludes it from being able to perform that job. Allthough if the tank never falls below 140f it might not be needed.

hot_rod

as long as the boiler return can rise above 130 in 10 minutes or less return protection is not so critical All boilers are condensing boilers on cold start 😉
A 3 pipe buffer gives you the best opportunity to buffer and assure rapid heat delivery, best stratification potential

If you can find a rep or get Pierre to run a simulation it will show how the various tanks perform at low tank temperatures You can get a tank to cover many performance options with some number crunching and proper selection

Really no substitute for a tank full of copper when it comes to heat transfer

JakeCK

Thats my biggest issue now. How the exchanger in my current boiler is in such good condition even though the return water temp is almost never over 130, unless its in the teens, is amazing. The only thing I can think of that is protecting it now is the old flue designed for coal. Its probably got enough draft to suck up the family cat.

hot_rod

The flue piping takes a big hit when boilers run cold most of their lives. Rust around the divertor hood, under the burners at the roof termination, etc are all signs and potential safety concerns if the boiler has been condensing

Cast iron boilers themselves can take a lot of abuse for many years, look for damage in the entire combustion and venting path

JakeCK

i figure there is damage in the flue. Its an old masonry chimney that runs outside if the house. Thing is like 35-40ft tall too.

In the pic the flue the boiler uses is the one towards the back. The front flue is for the fireplace. There is a second chimney in the back that you cant see over the roofline.

JakeCK

So I did some poking around and I did not find any signs of condensing or corrosion on or around the boiler. I wasn't able to get up on the chimney though. I don't like heights.



Here are a few pictures I took.

clammy

It looks like you may have a slight flame roll out condition looking at the burner compartment on the left hand side usually there a roll out sensor but your boiler may not have being it’s a few years old . What type of heating elements do you have cast iron rads or wall convectors ,even though there may not be signs of flue condensation at the boiler I would assume the flue temps in the chimney are low enough to damage it ,also even though there’s no rust on the flue divertor there may be signs in the horizontal flue pipe and take a look at the outside of your chimney for signs which usually include white or yellowish staining usually 1/3 from the top of your chimney in mild cases .i see unlined chimneys all the time and the signs of condensation on the masonary but no signs at the heat exchanger .whats the btu rating on your existing boiler and about how many sq ft is the home ,as others have stated a danfoss thremic valve to protect your boiler would be a smartness investment .using a turbo max just for domestic hot water is fine they perform very good and I ve had no complants from any I ve installed ,I have not used them as a buffer as you described just haven’t found a system that truly warranted it after all was said and done . Peace and good luck clammy

clammy

On another note your system may have been better suited to be piped primary secondary w return temp protection for the boiler while maintaining a constant system flow which would still most likely run your systems temps low while protecting your boiler .a detailed heat lose and complete btu rating of your heat emitter may enable you to heat your home a a lower water temp then possibly the use of a outdoor reset controlling system temp could be a Possibility Just some food for thought Peace and good luck clammy

JakeCK

No staining on the chimney, 115000btu is the rating, 1460sq ft 90 yr old house with cast iron rads.

I'm actually planning to repipe the whole system in the basement, it is why I'm here. see this post for a lot more info, i actually did a heatloss and posted it there. The only reason I posted these pictures on this older topic was because hotrods reply.

https://forum.heatinghelp.com/discussion/171144/buffer-tank-4-pipe-vs-2-pipe#latest

JakeCK

As for the flame rollout, I hadnt noticed that. I will have to call in a pro to do a combustion test and draft test for that. I do not have the equipment for it.

clammy

It actually looks like a plate is missing from above the burner tubes that would case roll out

JakeCK

The plate I had removed just to get a picture. It was sitting on the floor out of frame. It is was replaced immedately after taking the picture.

JakeCK

clammy said:

It actually looks like a plate is missing from above the burner tubes that would case roll out

So I had a local professional, one I found through the site, come in and do a checkup on the boiler. He did test combustion and draft, and looked for any rollout. Everything checked out. Actually seemed confident I could expect many more years if not decades of reliable service from the boiler. I won't name him unless he wants to come forward but I will added he is respected on the site. Shouldn't be hard to figure out since there are only two local companies on this site for the Cleveland area. Also I am very happy with the service. And more so that I can expect to not have any unexpected surprises.