Compare indirect DHW

[mchild]

I have been looking around at indirect DWH tanks and was wondering what the pros thought of the Buderus S series versus the Triagle Tube Smart 30?

While the Buderus is 32 gallons against the TT 28, the Buderus has a coil that has to reduce that capacity or is the 32 net of the coil? Is the coild a better way to heat the water than the outer tank method used by TT? How does the ceramic coating of the Buderus compare and hold up to the stainless steel of the TT?

[mchild]

johnsp - you out there? Hoping you would weigh in on this.

[danielworkerbee]

I like the Superstor, all stainless steel, lifetime warranty?, boiler water thru the coil. Make sure you read the manufactors spec's on GPM flow required to achieve alot of hot water. luck dan

[casturbo]

I like Mega-Stor, priced right, high output, easy to install.

I wouldn't buy/install a foreign tank (Buderus, TT) unless there wasn't something equivalent domestically.....but there is.

[Freezeking2000]

I like Mega-Stor, priced right, high output, easy to install.

I wouldn't buy/install a foreign tank (Buderus, TT) unless there wasn't something equivalent domestically.....but there is.

Just put in a 40 gallon Mega Store yesterday in my own home.

Make sure you size it so the boiler will not cycle when running domestic only.


Great unit the Mega store

[smadave]

Take a look at the Monitor BS tanks. Very nice tank, good design. Check it out at www.monitorproducts.com

Dave in NJ

[mchild]

Lots of great recommendations. Keep them coming. I'll check each of these out.

[johnsp]

probably has slightly better performance numbers then the Buderus. The TT has 1" boiler piping, less head pressure. If you're using a low mass boiler and your water is normal (no high chrlorides), I 'd say TT since it holds 5 or 6 gal of boiler water, helps a bit in short cycling. Is your HW load very small? If not, go for a 40 indirect. Especially if the Buderus tank costs more then the TT. The TT does not have a clean-out. But if you're not on well water or have a high amount of minerals in your water, I don't see a need to ever clean out an indirect.

[mchild]

johnsp

Thanks for your comments.

In other postings you have advised me to go with low-mass, three-pass units. I liked the additional effective capictiy that the TT gets by not having a coil and the fact that it is stainless.

We are on well water so there are no chlorides, but I don't know how much mineral build up we get. We currently have a propane fired 50 gallon unit. We have never run out of hot water even with an occasional back to back to back shower. I don't know if it is more than we really need because I do not know how to calculate the size that a hot water tank should be. Is there a formula?

Thanks again

[johnsp]

Crown Boiler's calculator in their Mega-stor doc:
http://www.crownboiler.com/manuals/c.../Mega-Stor.pdf

I assume you're going oil? (3 pass) I would first figure out your heating load.
Now get a tank that can driven by that boiler within your budget and space limitations. Realistically, you can't run 2 shower and washing machine all at the same time on a 30 gal tank with a 60K boiler. As long as you're not filling a jacuzi tub and only run 1 appliance, I would think a 40 gal indirect is fine.
Think about any expansion you plan on doing. If you're adding bathrooms,
chances are you get 2 or 3 people wanting to shower at the same time each morning. If that's the case, move up to a 60 gal. Just check the BTU requirements you'll need in the boiler to drive it.

[mchild]

johnsp,

Thanks again for all your guidance. The heat load is 80K, and yes, I'm going to fire the boiler (Biasi or Burnham) with oil. I have only seen on a couple of tanks the required BTU's but I'll look more carefully for it on others.

We have no expansion plans and no hot tubs. I have assumed that something in the 30 - 40 gallon range would be sufficient, but it would be nice to have a way to calculated it. I'll check out the Crown site.

What about the fact that we are on well water? Should I be looking for a tank with a clean-out?

Thanks again,

Mark

[mchild]

johnsp,

I checked out the Crown calculation. My boiler is going to provide supplement heat to two heat pumps and the DWH will have priority. Do I need to size the boiler based on the greater of the heat loss or DHW demand as called for in the Crown formula? Or, in the setup that I will have, do I only size it for the heat loss? Heat loss is 80K, but using the Crown formula (I fall between the 26 and the 40 so I assumed the 40) would push it to a boiler with 124K gross or 108K net – 28K greater than my heat loss. Is this correct?

Thanks

[Freezeking2000]

johnsp,

I checked out the Crown calculation. My boiler is going to provide supplement heat to two heat pumps and the DWH will have priority. Do I need to size the boiler based on the greater of the heat loss or DHW demand as called for in the Crown formula? Or, in the setup that I will have, do I only size it for the heat loss? Heat loss is 80K, but using the Crown formula (I fall between the 26 and the 40 so I assumed the 40) would push it to a boiler with 124K gross or 108K net – 28K greater than my heat loss. Is this correct?

Thanks

You should size the DWH to allow the boiler to run constantly until satisified on tank temp controll. I have a 40 at 8 GPM flow and my boiler running a .85 at 140 psig runs without cycling at all. I do not believe you will need the priority either, I have not had an issue even with temps in the single digets, more hot water than I can ever use.