Weil McLain EG40

Dave0176

Hi all new here, and kinda new to steam. Have installed a few systems with an old timer but have done mostly hot water and forced air. I am a licensed contractor and lately I've got a few steam replacements come up. First one will be replacing a 70 year old American Standard oil steamer. It is rated at 390 sq ft steam and fired at 1.4 gph. I did an EDR and total radiation was 285 sq ft so Weil McLain chose the EG40. My question is on header sizing, the manual calls for 2 1/2" riser and header, is this going to be enough or should I size it up to 3". He has two supply mains running to both sides of the house. Just want make sure dry steam gets to those radiators.

Dave0176

Forgot to add

BTW am converting to gas. Also is a parallel flow system.

Unknown

show us

Show us the pictures of the steam bolier replacment you did ....

Dave0176

Install

I haven't installed it yet just getting info, but will def post pics when done.

Hap_Hazzard

Near-Boiler Piping

The purpose of the header is to separate the steam from any water it might be carrying. To accomplish this it needs to slow the velocity to about 15 ft/sec. To determine the right pipe size for the header, you need the total output in cu. ft. per second, which can be calculated from BTUH, divided by the cross-sectional area of the pipe (in sq. ft.) to give you velocity in ft./sec. Or you could ask Joe Starosielec (aka JStar), who has worked out the numbers for the most common pipe sizes.



In general you should not use anything smaller than the riser ports as system risers. If there are two riser ports, use them, even if the manual only requires one. The boiler risers should extend to at least 18" above the maximum water level, but more is better. The header should have at least the same cross-sectional area as the risers combined. For two 2" risers, use a 3" header. There should be at least one diameter separation between the two riser connections to the header and two diameters between the last boiler riser and first system riser. The diameter of the equalizer should be the same as the header down to the water line.



Most important: if any of the pros here tell you anything different, LISTEN TO THEM. I've basically learned everything I know from them. They are the ones with the real-world experience.

Dave0176

Thanks Hap Hazard

The EG40 boiler has two 3" riser tappings and the manual did only suggest one riser. I always wondered if you can use both those tappings.

Dave0176

Near boiler piping

So now another question?? Since the boiler is tapped for 3" risers, do I run two 3" risers? Seems a little big for 125,000 btu?

Hap_Hazzard

You can't really go too big

Using both risers tends to keep the water line more level when you're running full blast, and the low velocity on a vertical rise will allow even very small droplets to coalesce and fall back. Of course you may not need as big a header as if you had 2" risers. You might be able to get away with 3" pipe for the header too, but let's see what the pros say. I'd feel better with a 4" header, but 3" will cost less.



Another thing I forgot to mention above is that each main branch should be supplied by its own riser from the header. Ideally you want a full-port ball valve on each system riser. This allows you to blow down the boiler through the mud leg, but it's also good to have if you need to fix a leak without shutting off heat to the whole house.

SWEI

EG40

Weil-McClain recommends 2-1/2" for both riser and header.  Working from Joe's http://www.heatinghelp.com/forum-thread/146979/Steam-Formulas numbers, I get:



Net output 104,000 BTU/hr (disregarding the pickup factor because this piping needs to handle all the heat the boiler can produce) that calls for 2-1/2" pipe.  Split that in half (two risers, 52,000 BTU/hr each) and you get 2" pipe, which still leaves a 25% safety factor for imbalanced output between the tappings.  I'd probably use 2" risers and a 3" header (one size up just for good measure.)  Nothing wrong with using 2-1/2" or 3" risers if you can afford them.

ChrisJ

EG-40

If you click on the link in my signature you'll see how I piped my EG-45.  An EG-45 is identical to the 40 other than burner size and draft hood.



I would have liked to use two 3" risers into a 4" header but simply couldn't afford it so I went with two 2" risers into a 3" header.  I found it to produce very dry steam even with oily water in the beginning.



After the install make sure you skim!  That will be just as important as the piping in the end.  I had to skim 6 times and ended up building a wand to wash the boiler out from the inside with hot water. 

Hap_Hazzard

Glad you showed up

You can't beat experience.

ChrisJ

Always

glad to be helpful when possible.

Dave0176

ChrisJ

Chris that is awesome looking job right there, it's burned into my head now. One question though why did you drop so much going into the header?? Wouldn't a 2" or 3" drop been enough??



Also the my guy at the supply house wants to know how you remove the plug on the second tapping because he said Weil puts them in so tight. I have 36" and 48" pipe wrenches so it shouldn't be a problem.

Dave0176

BTW

Also tomorrow I'm doing another steam job for a small apartment building with separated boilers, one went bad when the tenet fired it with no water. I'm installing a Weil PEG 30 75000 btu. Question should I run a second riser?? Looking at the chart it doesn't seem like it needs it??

ChrisJ

Dropped

I dropped it that much because I felt it would make connecting the mains into it easier. I had never done this before and most of it was ordered by eye and then the last few pieces I had cut and threaded at a local place. Afterwards that was one of the first things I thought, would've looked better if it was up higher but I don't think it effects anything.



My block came with no plugs installed. The plug for the second riser came in a box.



I would use two 2" risers minimum on any steam boiler no matter how small. Two risers always works better than one and its really cheap to do with 2" pipe and fittings. You can probably get away with two 2" into a 2" header on a peg-30 and it will run beautifully.

Dave0176

Chris

ChrisJ thanks much for help.

ALIGA

removing the second tapping

i read up about the candle trick of getting wax into the threads, after doing that, the tapping came out like a peice of cake.