Indirect DHW Question

Cyclist77

So now that the boiler,Weil-McClain CGa,boiler has been selected I am looking at the indirect dhw tank. I see Supply House has a unit,Triangle Tube. It is SS tank and coil. As am not familiar with this brand I was wondering what you fellows think?

Or are all of the indirect basically the same?

Thanks!

Grallert

Which model? If it were me I'd choose one with a coil in the tank simple because they are easier to drain if you ever have to.

Alan (California Radiant) Forbes

Triangle Tube has their SMART line of indirect tanks. Personally, I’m not fond of them as I’ve had to replace a few that have leaked; one, last month.
I prefer Viessmann stainless steel indirects.

GGross

Some things to consider about indirect heaters and their price/features. Some come with an aquastat built in, some ship without a relief valve. Of the brands I am most familiar with (triangle tube and viessmann) the TT has a built in aquastat, but historically does not ship with a relief valve, the viessmann ships with a nice relief valve but no built in aquastat (they assume you are using their sensors that ship with the boiler) I have liked using the hydrolevel acutemp aquastat on the viessman indirect, just have to provide 24v to it, it's nice as you can use the sensor ports on the indirect and remote mount the aquastat control to a wall somewhere more convenient so you can fiddle with the temperature to your hearts desire.

Ironman

If your water is high in chlorides, like from a water softener, then you don’t want to use a stainless steel tank. Use a glass lined one like Bradford White offers.

As far as stainless ones go, most are good, but HTP is usually the most preferred. The ECR (Utica) H2O are also good.

hot_rod

How's your water. Test for chlorides if you want a stainless tank.

I have had the best luck with glass lined steel tanks. This tank is sold under different brand names. Bock, Laars, now BW, Lochinvar.

Dual anodes, brass drain, large smooth coils, a nice pro quality tank.

How much hot water are you needing? 40- 50 gallons covers most homes, unless you nave a large soaking tub or other high load need?

tcassano87

I have a Weil McLain Cgi Gold( obviously different but the same). With a Weil McLain Aqua Plus In-Direct tank and it works absolutely great. Can choose to wire it to a switch relay with priority or like mine it has a seperate relay that gets wired directly to the boiler

ethicalpaul

LRCCBJ

Here is the dirty secret about the TT smart indirects:

From the I&O manual:

Never use water heater unless inner and outer tanks are completely filled with water.• Inner tank must be completely filled and pressurized before pressurizing outer tank.

Now, think about what happens if you shutoff the supply to the house (or to the indirect) and someone opens a faucet anywhere in the house………….

The inner tank loses all pressure in about two seconds.

The seal between the inner and outer tank fails and that's the end of the indirect.

DO NOT PURCHASE A TT SMART INDIRECT.

EBEBRATT-Ed

I think the Weil McLain tanks had a similar sticker on them.

hot_rod

I think that tank in tank design is just two nipples from the inner tank welded through the outer tank. Not unlike how the coils of a typical indirect exit the tank? I don't know of any other seals?

I'll bet many of the tank in tank have been filled and started incorrectly. I know I have😯

That design has been around what 30 years or more, there must be enough of them working well?

Debatable whether they outperform a coil type of the same square footage HX. They could be less scale prone.

Draining was the biggest issue, you had to plan for that.

LRCCBJ

I think that tank in tank design is just two nipples from the inner tank welded through the outer tank. Not unlike how the coils of a typical indirect exit the tank? I don't know of any other seals?

You may think so but you have to be incorrect. The tank fails immediately when the inner tank loses pressure. TT actually tells you this in their own words.

Ignore it at your peril.

EdTheHeaterMan

Weil McLain's Plus series indirects came with a lifetime warranty. They were the Triangle Tube tank in tank design and after about 15 years in, the failures started to happen.  Then they adjusted their lifetime warranty to a prorated lifetime warranty on all the new tanks sold that were in stock.  They have discontinued that model.

I remember swapping out about a dozen Plus 30 and Plus 40 tanks as time went by.  I saw the change in the warranty from a “no questions asked” to the point where they wanted you to test the temperature sensor well (most common failure point) and replace it if possible before you could qualify for a warranty tank.  That added a few years to the tank and the pro-rated amount was less when they finally approved the replacement a year or two later.

Not a WM fan!

Kaos

If you already have a plate HX/pump/tank, I would use that till it starts leaking. That setup has better efficiency and faster recovery than most indirects.

Once that fails, I'm with @ethicalpaul get a HPWH. Indirect with high mass boiler does not make sense, from BOM cost or from operating costs.