Why does a 17000 btu electric boiler have 1 1/4 inch taps?

NL_plumber

My understanding is that 17000 btu's on a system with a 20 deg. temperature drop would require only 1.7GPM which could be supplied by 3/4 inch pipe. The only reason I can think of is the boiler could be installed as part of a multiple boiler setup supplying a much larger system which would require the larger pipe. I have wandered this before with other small boilers but have never come up with an actual answer. I used 1 1/4 inch pipe to the air scoop and then the circ. pump and then bushed down from there. Would it be alright to bush it down right at the boiler?

hot_rod

sometimes that one block gets used for a range of outputs. Just add additional, or higher KW elements. Cast iron boilers also, even a low BTU boiler might have the same tappings as larger sizes.

NL_plumber

That makes sense, thanks.

Hilly

All about keeping manufacturing costs down, which hopefully keeps our costs down in the end.

bmwpowere36m3

You'd think they could throw in a bushing for a few cents... Does the I/O manual offer any recommendations for piping?

NL_plumber

Yep, piping diagrams were included just no information on the pipe sizes which is normal. I just didn't like bushing down right off the boiler, it didn't feel right if that makes sense.

wogpa67

I use Bell reducers all the time for that. Why install bigger air separator and isolation flanges then you need to.

bmwpowere36m3

If you're going to reduce down at some point… then it doesn't really matter. It'll be a restriction here or there.

SWEI

We keep 1-1/4" x 3/4" 304 stainless bushings on hand for the small Thermolec models.

NL_plumber

yep, i'm good with it now. Bushing will be going right on the boiler next time. the 1 1/4 inch to the seperator does make it nice and sturdy though......

Hilly

Well you're in NL so it's a 80% chance you're using Slant/Fin. If you use a hex bushing you'll need a big socket or you'll have to remove the casing to get bushings installed with pipe wrenches. You're better off using a nipple and reducing coupling cause you won't find a swage nipple either. If you're using line scoops you'll only get 1.25" or bigger so bushing downstream the line scoop will be easiest. you should go to a air seperator instead. In which case using a nipple and reducing coupling will give you the chance to reduce the A.S. and save some money. Phew... Lots of words there... I hope I made sense.

SWEI

A surprising number of our Thermolec installs are in tight quarters (closets, basically.) A nipple and bell reducer effectively add another ~2" to the width of the boiler. We install the bushings in the shop using an anaerobic threadlocker so the tech needs only 3/4" and smaller fittings on site.

Hilly

Come to think of it, the new slant/fin come with a nipple and 1.25"x.5" tee. That's where they want their well and boiler supply sensor installed. Apparently they had lots of trouble with people not applying the insulation around the sensor or just plain not installing it. With the tee and nipple it makes you go out if your way to not install it. Which still happens. I heard they were going to eventually change the castings to have it factory installed under the casing. Last couple I brushed down at that tee.