Vento blast coil

t. tekushan

Building type: Theater, 1926

Existing system and its artifacts: Vento steam/forced air central heating and ventilation set up in conjunction with radiators for lobby, stage and restrooms. The Vento consists of a heat exchanger room with an array of vertical cast iron waffles through which air is drawn. U.S. Blower Corp Scirocco fan system. ALL supply air is fresh air from outdoors (!). We are going to reproportion the amount of fresh air intake to reflect modern code.

Problem: How to properly estimate the revised boiler size required based on these changes.
If I had specs for the Vento I could figure it out from there. The theater space potentially consumed up to an estimated 75% of the original Kewanee 100 HP modulating firetube boiler. But I don't think we need the Zero degree correction factor anymore, among other things.

Any info out there?

Steamhead

Yes there is

I have it in one of my Ideal Fitter books. Watch this thread, I'll post it when I find it.

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Steamhead

Found it

From the 1925 Ideal Fitter. It doesn't give the CFM at which the ratings were taken though.

What type of steam system are your Ventos attached to?

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john_27

vento

I've got to check, but I would guess that your theatre was sized using the Mills Rule, and then upsized 70% to allow for zero degree outside air....a much safer course of action for you would be to size the radiation to the load instead of guessing that the original boiler was accurate. I think the steam section of this site deals with ventos...if not, just let us know.Also, when you close off the outside air, you need air changes from somewhere else or you will have hot ventos and cold rooms...for myself, I run outside air through January,inside ducts during the two coldest months, and outside from late March on...good luck!

t. tekushan

Thank you, thank you!

In a way, it is unfortunate that so much of the original boiler apparatus is missing. The theater is on separate zones from the rest of the building, the theater having the "radiator" zones, and then the Blast Coil zone.

Originally one 100 HP boiler ran everything. The residential and non-theater commercial zones now have separate boilers.

The system is a two pipe low pressure steam, and there are vestiges of condensate pump hardware, feed pump, etc. The old gas modulating valve with the chain and weight is still attached to the remains of the Iron Fireman in the fire pit. Top shelf stuff of the era methinks. The Vento room is still fully equipped but has been out of service for a least a decade and has been subject to what I hope is surface rust due to moisture from above.

This info will give me what I need to make the proper calculations (although a little seat of the pants intuition may come into play as well).

Thanks again...

t. tekushan

Thanks so much for your input.

We have a clear path to install return ducting and will easily(relatively) be able to alter the fresh:recirculated air ratios. Changing it seasonally is a great idea.

I have a line on a Peerless 45 HP boiler locally that may fit the bill (gotta watch the budget-- new roof needed, plaster repair etc. According to my rough calcs here, I think 45 HP is more than adequate.

Thanks again.

JLR

duct design/ ventos

john, can you share info how you modified duct work for either fresh or inside air flow.