Boiler Replacement Question

DetroitSteam

I have a contractor getting ready to install a new boiler at my 7 unit apartment building. He wants to install a Weil Mclain EG-75 300,000 BTU/hr Steam Boiler. It looks like this boiler is rated for 750 sq. ft. of steam. The radiators in the building hold 640 sq. ft. of steam (this does not include any of the pipes leading to the radiators). He also said that he will be having a single riser out of the boiler. I asked him if we should consider doing a drop down header or increasing the header by one pipe size and he told me there would be no value in doing any of this. Before moving ahead with the install I wanted to get a second opinion regarding the single riser, boiler size, and near boiler piping from the forum. This is a single pipe parallel steam system. The current boiler is leaking most likely due to lack of maintenance by the previous owner.

JStar

Eg-75

http://www.weil-mclain.com/en/assets/pdf/eg_boiler_manual.pdf



This boiler only requires one 3" riser and a 3" header. That is a minimum recommendation. You would definitely benefit from 2 risers. If the boiler had 5 tappings, you should use 5 risers. The more risers you use, the slower the steam's velocity will be...which is a good thing! A drop header will be just as much of an advantage in keeping the steam as dry as possible.



For 640 sq ft of radiation, I would hae chosen the EG-65 model.

ChrisJ

Just a homeowner but,

If it was me I would go for the EG-65 assuming your calculations on radiation are accurate.  I would also insist on TWO 3" risers out of the boiler even though WM states a single 3" is the MINIMUM required. 

I would do two 3 inch risers out of both the EG-65 and EG-75 regardless of the minimum and I would recommend a 2 inch equalizer not a 1.5".



I installed a EG-45 in my home which is much smaller and still used two risers.

DetroitSteam

Boiler Size

Since the sq ft of steam for the radiators is 640 shouldn't that be multiplied by 1.3 to make up for the size of the pipes? This would bring the total sq. ft. of steam to 832. It appears that the EG-75 is only rated for 750 sq. ft. of steam.

ChrisJ

pickup factor

The EG-65 is rated for 640sqft of radiation and this takes the 1.33 pickup factor into consideration meaning its actually good for 851.2 sqft. The 640sqft is for radiators only, don't worry about piping.

DetroitSteam

Crazy Weil-Mclain Employee?

I finally got ahold of Weil-Mclain and they confirmed that the EG-65 would be a better size and that it is rated with the pick up of 1.333 in mind. However, they said that adding a second riser or drop down header won't benefit me and that they wouldn't recommend anything more then what is in their manual. Was this employee crazy?

ChrisJ

Crazy?

Nope, they probably just don't know any better.

Patrick_North

Possibly politics...

It's a poorly kept secret that manufacturers are reluctant to demand the kind of near boiler piping usually recommended here simply because it makes their product more expensive to install. Because most homeowners don't understand the benefits associated with the greater expense, installers may be reluctant to suggest such products for fear of losing bids. Crazy, huh?

The added expense is not so great, and the benefits are real and long lasting. I'd stick by your guns and insist on the piping recommendations offered here.

Good luck,

Patrick