hot water help

bdan

   My Weil-McClain

oil-fired steam boiler has developed a leak in the tankless coil providing

domestic hot water, making it necessary to drain a five gallon bucket every six

hours or so to maintain the proper water level. Due to its age (over 40 years,)

I’m replacing the boiler.  I’m also taking

the opportunity to convert to gas at this time; getting all the paperwork into

the gas company by yesterday’s deadline for a $2000 conversion rebate.





   I’m going to stick

with my 1920s one-pipe steam system as radiator replacement and a full repipe

of my 2 family house for hot water heat would be too expensive and the steam

heat is pretty well balanced throughout the house(especially after insulating

the upstairs walls and ceilings two years ago.) I’ve decided on an

electric-ignition Burnham IN6 as this meets the “efficiency” requirements

(AFUE=82.5) for an additional $500 rebate.





   My questions

involve the production of domestic hot-water. I initially thought an indirect

HW heater was the way to go (and qualifies for another $300 rebate). After

doing some research, though, I’m not quite sure. I’m having a larger gas line

brought into the utility room so I could go with any option, however, my

plumber said the flue to the chimney is too low for a standard gas hot water

heater- would need a big hole made in my foundation up higher.  My biggest concern is whether the efficiency

of an indirect tank will be realized with such an inefficient boiler. The

boiler sits just under the living room, which bakes already in the summer sun,

requiring substantial AC. I’ve also discovered that using a steam boiler voids,

or substantially reduces the manufacturer’s warranties.





   I’ve found several

scenarios on the net describing how to use a steam boiler with an indirect tank.

Here are two popular ones:





1)<a href="http://www.google.com/url?sa=t&source=web&cd=1&ved=0CCIQFjAA&url=http%3A%2F%2Fwww.heatinghelp.com%2Ffiles%2Farticles%2F1360%2F346.pdf&rct=j&q=indirect%20water%20heater%20steam%20boiler&ei=eRlsTc61I8qEtgef59jmAg&usg=AFQjCNF23pzG0ynngfvlIwLqIlWifQ8w3A&sig2=7">http://www.google.com/url?sa=t&source=web&cd=1&ved=0CCIQFjAA&url=http%3A%2F%2Fwww.heatinghelp.com%2Ffiles%2Farticles%2F1360%2F346.pdf&rct=j&q=indirect%20water%20heater%20steam%20boiler&ei=eRlsTc61I8qEtgef59jmAg&usg=AFQjCNF23pzG0ynngfvlIwLqIlWifQ8w3A&sig2=7





2)[url=http://google.ad.sgdoubleclick.net/pagead/nclk?sa=L&ai=1&fadurl=googleads.g.doubleclick.net&u=http%3A%2F%2Fwww.comfort-calc.net%2Fsteam_indirect_piping.html&aclck=http%3A%2F%2Fsmart-search-directory.com%2Fsearch.php%3Fkeyword%3Dindirect%2Bwater%2Bheater%2B]http://google.ad.sgdoubleclick.net/pagead/nclk?sa=L&ai=1&fadurl=googleads.g.doubleclick.net&u=http%3A%2F%2Fwww.comfort-calc.net%2Fsteam_indirect_piping.html&aclck=http%3A%2F%2Fsmart-search-directory.com%2Fsearch.php%3Fkeyword%3Dindirect%2Bwater%2Bheater%2B





Any advice on these or any alternative methods would be very

helpful. My goals are to make my setup as efficient as possible (annual average-New

York- cold winters, hot summers) and to bring the temperature of my hot water

down to a safe temperature for my two young children (currently scalding with

tankless coil despite cold water bypass).





Thanks in advance for opinions on this or any hot water

alternatives.</a>

bdan

sorry about links

www.comfort-calc.net/steam_indirect_piping.html

www.heatinghelp.com/files/articles/1360/346.pdf

jimmythegreek

many choices

In my opinion using a steam coil for domestic in an indirect setup is great for hot water, not so great for steam.  If you have a large demand for hot water, it can be beneficial, but usually not.  Unless your willing to have a dual setup, which I do, its prob not worth it.  I have 450k btu steam boiler, and its in a commercial building with alot of water demand, theres a restaurant tenant.  We use the steam for heated hot water  because its basically free, just the setup cost upfront money, the heat is on 5 months out of the year anyway, so the water is heated basically free.  The other 6-7 months we switch to a double hotwater gas heater setup, one feeds another tank, both direct fired.  I used a regular 80 gallon for the second tank, and a 75 gallon high demand for the first.  The inderect tank is 80 gallons and is piped with a loop out of the steam boiler and has a control on the storage part of tank like an aquastat to measure water temp and fire the boiler if hot water is needed.  Its very efficient in the winter, prob raises my gas cost 10% tops.  Im at $300 avg for the 2 water heaters a month when they are in use part of the year.

In your case you may be better off with a tankless wall hung water heater, they are very efficient for residential use, depends on the height.  You could always go with a standard water heater, or even electric but you have gas so why bother.......

 

bdan

thanks

Thanks, Jimmy. Quite a nice setup. I'm figuring indirect with steam isn't the route to go right now. Do you know some good brand names of tankless wall heaters? My plumber had mentioned something like that. What do you mean by  'depends on the height'?  Do you know the venting requirements?

   Our current demand for hot water is slight, a few dispersed showers, occasional laundry and thoughts of a future 2-3/ week dishwasher

Charlie from wmass

Bdan

Oil fired steam boilers can be 86 percent efficient. They also can have a coil installed if the coil produced enough hot water for you it may still work if properly set up. Indirects with steam boilers work well and use less fuel per gallon of hot water they make than using a tankless in the boiler. That said they are seldom plumbed properly. The Modern tankless heaters work well with good water quality, as in not too hard  of water. They also require proper installation or they are worthless. an IN6 sounds kind of big how did you get the boiler size? 

bdan

thanks

Thank you for your thoughts. I think I'll be going with a more conventional gas hot water heater.

I think the boiler that my plumber recommended is too big. I have the

old 38" tall, 3column steam radiators throughout the house and I'm

currently doing the calculations of EDR but have a few questions:



1)how to calculate the EDR of a steam baseboard radiator. This is a

radiator installed on a first floor addition consisting of a steam

valve, an 8' finned 1 1/2" pipe with a regular steam vent on the end.



2)do I need to include the BTU requirements of ~20' of recirculating hot water baseboard on a basement zone?



3)Once I multiply by 240(for steam) which specification am I trying to match



Input MBH



DOE heating capacity



Steam MBH?(I=B=R)







Thanks for any help.