btu's of hot water coils?

Rocky

> just wondering?? i'm giving an estimate on <BR>
> adding baseboard to an addition and trying to <BR>
> determine if the boiler would be large enough. <BR>
> basic raised ranch with addition going off back. <BR>
> my heat loss comes out to about 80,000. the <BR>
> existing boiler is a slant fin 129,000 btu <BR>
> output. BUT WAIT!! theres a hot water coil <BR>
> (maybe 5 gpm) forgot to look. how many btu's if <BR>
> any would i have to add to my 80,000 btu <BR>
> loss. thanks!! jim f. tri-city heating and <BR>
> cooling<BR>
> <BR>
> _A <BR>
> HREF="http://www.heatinghelp.com/getListed.cfm?id= <BR>
> 276&Step=30"_To Learn More About This Contractor, <BR>
> Click Here to Visit Their Ad in "Find A <BR>
> Contractor"_/A_ <BR>
<BR>

jim f

just wondering?? i'm giving an estimate on adding baseboard to an addition and trying to determine if the boiler would be large enough. basic raised ranch with addition going off back. my heat loss comes out to about 80,000. the existing boiler is a slant fin 129,000 btu output. BUT WAIT!! theres a hot water coil (maybe 5 gpm) forgot to look. how many btu's if any would i have to add to my 80,000 btu loss.
thanks!!
jim f.
tri-city heating and cooling

To Learn More About This Contractor, Click Here to Visit Their Ad in "Find A Contractor"

[Deleted User]

You'll be OK

> just wondering?? i'm giving an estimate on

> adding baseboard to an addition and trying to

> determine if the boiler would be large enough.

> basic raised ranch with addition going off back.

> my heat loss comes out to about 80,000. the

> existing boiler is a slant fin 129,000 btu

> output. BUT WAIT!! theres a hot water coil

> (maybe 5 gpm) forgot to look. how many btu's if

> any would i have to add to my 80,000 btu

> loss. thanks!! jim f. tri-city heating and

> cooling

>

> _A

> HREF="http://www.heatinghelp.com/getListed.cfm?id=

> 276&Step=30"_To Learn More About This Contractor,

> Click Here to Visit Their Ad in "Find A

> Contractor"_/A_

[Deleted User]

You'll be OK

The water heater will use the full output of the boiler, and the circulator will stop if the water temperature drops in the boiler (tankless coil water heater).

If you use an indirect water heater, still don't oversize for the water heater. You may consider wiring the water heater to take priority over heat, on a boiler this small, but don't oversize the boiler.

Noel

Big Ed

5 GPM Bah Humbug

5 gpm coil is a bit of a joke in most boilers.. The imput determines the output . You would need around 300K of input to get 5gpm of hot water output. The hot water production depend on input , unit eff and incomming water temperature to temp rise or gpm x 8.3(weight of 1 gallon of water in # ) x temp rise x 60 min = net Btu's

Example.... Take your 5gpm coil x 8.5 x rise 90*F( say 40*F to 130*F= 90* rise) x 60 min = 229,500 net Btu's needed say with a 80% EFF boiler 229,500 btu net / .8 EFF = 286,875 btu input needed with a 80% boiler to get 5gpm... And thats without a call for heat !

B. Tice

I've seen it

I have seen several coils used for sizable additions off steam boilers and worked good. However, steam boilers tend to have extra capacity. How about using Spirotherm element in some blank Slant Fin enclosure? The Spirotherm element puts out alot of BTU's with lower temps.

Big Ed

B. Tice

What is Spirotherm element ?

Rocky

Jim

What I've done in the past is put in a relatively inexpensive 50 gallon electric water heater plumbed into the coil with a bronze circ pump, then used a tekmar 260 to give me priority DHW. If boiler is close to max btu's, this will be a good alternative to bumping boiler size. Also gives customer outdoor reset fuel savings, plus gobs of hot water. My customers have loved it.
Happy Heating,
Rocky

Jed_2

Spirotube

Big Ed, are you familiar with the Spirovent? Well, If you are, you have access to Spirotube. The mesh bundle in the Spirovent can also be used in place of the fins on baseboard element. The mesh is welded on to 1/2" or 3/4" copper pipe. That's Spirotube. No enclosure. But they do have support brackets available. The idea is to custom build enclosure to accomodate the decor of the room. Btu/h output beats any residential element on the market. Pricy!
But very accomodating to custom design.

Jed

Big Ed

Thanks Jed

Yes I think I seen that somewhere , maybe in a trade rag .I never seen it out in the field though. I will check out their sight and try to find the ratings . You never know when you could use it. Thanks Again Jed

Roger_3

Priority should be a last resort

Have you ever seen a frozen house with the boiler running? Priorty for domestic hot water should be used only if you have a design flaw.When the boiler or inderect tank is sized properly you should not need priorty. See the post about the 5 gpm coil is it right on the mark. When sizing storage use a 1 to 1 metheod. (1 gal of storage per gallon of hot water needed)