Indirect off of new steam boiler - downsides?

ferenb01

Hello,
Massachusetts homeowner. Replacing steam boiler (small hole in current and was woefully undersized - who knew! used Dan's calculation method to size new). Inspector wants a liner in the chimney - can only fit a 7" oval liner - which means I cannot vent both the new boiler (weill mclain EG65) and the current gas fired WH. For DHW, my plumber (who I found from this site) is recommending we go with an indirect stainless tank off the new boiler. He looked at a Rinnai/Navien as well but venting and condensate line in basement configuration would make a difficult install. Other option is two 50 gallon electric with a tempering valve. So I guess I'm leaning towards indirect.

Plumbing inspector off the cuff said an indirect off of a steam boiler is not the greatest idea (in his mind). Why? What's the downside? Also, we are a young family - is a 45 gal indirect enough? or go with a 60 gal indirect? $500 difference.

Much thanks in advance for any help/advice.

nicholas bonham-carter

Perhaps the inspector is thinking of the summertime when the boiler will still have to run for hot water production.--NBC

Jamie Hall

The only downside I can think of is the need to fire the boiler from time to time in the summer. Some might regard that as not such a good idea. Some might regard that as an excellent idea, to keep it drier. I wouldn't have a problem with it!

Young family? Kids? I'd go with the 60. You may not need it right now, but later on... some folks like long hot showers!

ferenb01

Jamie Hall said:

The only downside I can think of is the need to fire the boiler from time to time in the summer. Some might regard that as not such a good idea. Some might regard that as an excellent idea, to keep it drier. I wouldn't have a problem with it!

Young family? Kids? I'd go with the 60. You may not need it right now, but later on... some folks like long hot showers!

Yes, 3 boys under age 5 - so currently it's one bath tub and two showers per day right now (plus sink, laundry).

Jamie Hall

ferenb01 said:

Jamie Hall said:

The only downside I can think of is the need to fire the boiler from time to time in the summer. Some might regard that as not such a good idea. Some might regard that as an excellent idea, to keep it drier. I wouldn't have a problem with it!

Young family? Kids? I'd go with the 60. You may not need it right now, but later on... some folks like long hot showers!

Yes, 3 boys under age 5 - so currently it's one bath tub and two showers per day right now (plus sink, laundry).

Just you wait.

EBEBRATT-Ed

I feel you would be fine with the 45 gallon. Why install an indirect that the boiler is not capable of heating?? A hot water zone or indirect off a steam boiler is not supposed to be larger than the pick up factor of the system

Bob Gagnon plumbing and heating

You will lose a little efficiency when you heat the domestic tank with a cast iron boiler, but if you get a stainless steel tank it'll be guaranteed for life, I would go with the 45 gallon.
Thanks, Bob Gagnon

HVACNUT

No comment on stainless tanks, well maybe 1, lifetime guarantee = lifetime problems and guarantee doesn't include labor.

Recommend use of a bronze circ, a wye strainer. Wire a L4006A in parallel into the boiler to maintain 140-160 during the summer.

gennady

Indirect off steam boiler is Ok, I do it all the time. Make sure you install DHW mixing valve. In heating mode due to temperature stratification top of the tank may reach very high temperature. You can consider storage tank off boiler coils. You will need expensive circulator but tank is cheaper. Downside is necessity to replace anodes regularly.

j a_2

Tell us more about the venting issue
Horizontal run and chimney height
What is the total btu load going up the chimney
Was a seven times calc. done for the chimney and water heater

Bob Gagnon plumbing and heating

Hey HVACNUT, have you seen many problems with Stainless SuperStor tanks? I've only seen a few leakers in a lot of years.