steam relief

Brad White_191

I read "SF and SF" not SF and pounds. The valve seems over-sized by a factor of 2.5 but 15 PSI is what counts.

Thanks for the well-wishes! Susan, the kids are great- hope the same for you and yours.

Techman

steam relief

How do you cross the steam boiler rating of 663 sq.ft. of steam, to the boiler relief valve rating of 407 lbs.per hr. Thanks

Brad White_191

Trick question?

The relief valve rating has to at least match the boiler rating. One cannot count firing rate.

John T_3

If I know what you're asking:

1 Sq/ft of steam = 240 btu/hr

1 lb/hr steam = about 1000 btu/hr (970 btu/hr)

so 663 sq/ft steam = 159,120 btu/hr = about 164 lbs/hr

If you're trying to size this to a boiler however you shouldn't use the sq/ft steam capacity of the boiler but the btu/hr input which is not the same.

Techman

no trick

Hi Brad, Happy New Year to you and the Mrs. The relief valve is a Canbraco #13-511,rated at 407 lbs per hr and the steam boiler is a Peerless #EC/ECT-05-175-w/s ,w/663sq/ft/steam,D.O.E.rating-212,000btuh.I'm wondering if the relief is proper.the relief is 3/4" and the boiler has 2,2" risers.

Techman

Relief

John T. The only rating on the valve was that lbs/hr #,not BTU's

John T_3

But you're getting the sq/ft steam from the boiler rating plate correct? I always use the input rate from the boiler rating plate.

example: boiler input 400,000 btu/hr divided by 1000 = 400 lbs/hr

Techman

John

Yes,I got the sq.ft. from the boiler name plate. Your math is exactly what I was looking for. Thanks much!

RonWHC

Pressure Relief

& Pop Safety Valves should match, or exceed, the Gross Output Rating. Not the Input.