Why use an indirect water heater?

Timco

Sooo....

the boiler keeps the WH at temp? Is this more efficient in the summer than a regular WH?

T

Mr Homeowner asks...

Why use an indirect water heater?

Why would I use an indirect water heater in a system?

If I have a heat source (traditional CI boiler, a condensing copper unit, or even a tankless) and can temper the water down for domestic use, how would an indirect water heater benefit the system?

[Deleted User]

the water that circulates through your closed heating system

Is not the same water that comes out of your faucet. In order to provide warm water to the left handle of your faucet as well as the cold water on the right, you need to warm that water somehow. An indirect DHW tank just happens to be the most effective way of warming up the water that you need.

joel_19

Easy

you'll typically get alot more hot water . The boiler does not need to remain at 200f all day with an indirect . That will then allow you to let the boiler hang out cold ,warm or you can run reset . All are better than keeping it at 200f . Short cycling , when a boiler runs just to keep itself at 200 the cylces are extreemly short . This wears on components and increases sooting lowering eff .
Suffice to say we do not install tankless boilers , they are simply a poor investment

Constantin

Sure...

I prefer indirects over regular gas water heaters because it's one less combustion appliance to take care of, one less flue to keep happy, and they also have much lower standby losses.

A gas water heater usually has a very low combustion efficency and, worse, features a flue right up the center which substantially increases standby losses. Where a good indirect will lose maybe ½°F per hour, traditional gas water heaters have to fire a lot more to maintain internal tank temperatures.

Several contractors here have also commented that particular brands of boilers ought to stay warm all summer to minimize corrosion. Running an indirect off a boiler will allow just that. Plus, an indirect coupled to the right mod/con boiler will never run out of hot water and will produce it with great efficiency.

Mr Homeowner asks..._2

What brand indirect DHW tank is best?

What brand of indirect DHW tank is best, and how does one decide which size?

SVDW

indirect

Your're opening a can of worms here!:) Everybody has their own opinion (Ford vs. Chevy kind of thing). I have a Burnham AL series & I love it. I would look for a unit w/a stainless tank & HX b/c it will probably have a lifetime warranty & doesn't usually need an anode rod. This means I can pretty much forget about maintenance costs. My nat. gas bills average $38/mo in the summer & that includes the stove & dryer. We can't run the thing out of hot water even w/all the relatives over for X-mas or Thanksgiving. I also like the fact it keeps my boiler running once a day during the summer so no restart worries when the cold hits here in W.Mich. That initial cost seems high but I have never regretted it in view of the benefits. Good luck & hope this helps!

joe_66

Not all indirects need high temps.Viessman and triangle tube are built from the ground up with low temp hydronics in mind.Indirect heaters also have very little standby heat loss,Viessmann boilers do too.

joe_66

Phase III though viessman has a true no B.S. lifetime warranty (316Ti stainless)

Constantin

I have been very happy with my VitoCell 300 so far.

Like joe said, the thing has a no quibble, lifetime warranty. It also has very large tubes as a HX, so it can use lower supply temperatures and still quickly recover. Plus, Viessmann publishes a chart that details the performance vs. supply temperature, so you can dial in the performance with a reasonable chance of getting it right the first time.

I also happen to like the Phase III from Triangle Tube because of the super-large HX surface it has. As a result, it recovers even more efficiently than the VitoCell 300. This tank is also private-labeled for WM, where it's sold in conjunction with the WM Ultra series of boilers.

Participants here have also praised the Crown Megastor I have no experience with the unit, but it looks promising.

As for the size to choose from, there are many. It depends primarily on how much water you intend to use all at once. Big "dump" loads like jacuzzis, waterfall/bodyspray showers are the bane of any buffer tank... so the tank has to be sized to meet that load.

For example, let's say your home has two showers that can run at any given time. That's about 5GPM of water flow with regular, modern shower heads. Under those circumstances, I doubt you'll manage to run out of hot water anytime soon with a quality 50 gallon tank indirect and a powerful boiler to back it up.

However, you'll have know what your intended flows are (duration and quantity) and the heating capacity of your boiler to determine which model makes the most sense. All manufacturers publish first-hour ratings, though most require 180°F hot supply temperatures to achieve them. Other manufacturers publish ratings that allow you to choose your own supply temperature (which is a bit more complicated, but a better system IMO).